User Manual

Using StarGPS-NX
Using StarGPS
Using the USB-ASTAR cable

Using the GPS-USB cable

GPS Week Number Roll Over

GPS-NX01 Receiver

GPS-NX02 Receiver

Changing the GPS-NX01 and GPS-NX02 output settings

Using StarGPS-LX
GPS-6010/LX Receiver

 

This User Manual discusses the setup and use of StarGPS products. For additional information and tips on using the Meade Autostar and ETX/LXD telescopes I highly recommend visiting:

For more information on Celestron NexStar I recommend visiting:

 

Using StarGPS-NX

This section describes how to use StarGPS-NX. You may also wish to download a copy of the "StarGPS-NX Quick Start Instructions" which are in PDF format.

General Information

StarGPS-NX includes a high-performance GPS receiver and one adapter cable. Adapter cables are available for use with Celestron NexStar, NexStar+, StarSense, Meade Autostar, Audiostar, LX200 Classic, Losmandy Gemini, Gemini-2 or Gemini-2 Mini, Astro-Physics GTO and Synta (Orion Atlas/Sirius, Sky-Watcher SynScan). The GPS-NX03 can also be used with the Meade LX200GPS, LX200R, LX200ACF, LX400ACF and RCX400.

  1. The GPS-NX01, GPS-NX02 and GPS-NX03 receiver status LED indicates:
    1. Solid on: power turned on (the LED is fairly dim and can be difficult to see in daylight conditions).
    2. Short-off blink every second: determined telescope type.
    3. Rapid sustained blinking: detected old NexStar firmware (requires update). Older GPS-NX02 and GPS-NX01 receivers require a firmware update (contact us) to resolve this problem for use with StarSense handsets.
    4. Rapid blinking for 5 seconds: no telescope found, switching to 9600* baud NMEA output.
    5. Short-on blink every second: determined date, time, latitude and longitude. This may not work indoors and normally takes about one minute outdoors.
    6. Short-on blink every two seconds: telescope has accepted GPS data.
  2. After the telescope has accepted the GPS data it can be disconnected. It is recommended to leave the GPS connected for at least twenty minutes following its first use (this allows it time to download and update the almanac and ephemeris data used to locate satellites, resulting in better performance
  3. Note that the local date and time are set to UTC (Coordinated Universal Time).

* GPS-NX01 and GPS-NX02 receivers NMEA output is at 4800 baud.

 

Astro-Physics GTO

StarGPS-NX uses the Meade LX200 Command Set to send GPS data to the GTO.

Note: For the most efficient use of StarGPS with your Astro-Physics GTO system, we recommend that you change the way you have your keypad set up. Since the GPS uses Universal Time, and the keypad starts from local time, there is the potential for timing issues that affect precise calculation of the meridian (overhead hour angle) and the horizons. While these issues will not affect normal go to operation during a night of observing, they can affect syncs done very close to the meridian, and they will affect park position calculations adversely. Either of these situations can result in the scope being driven into the mount, so it is important that you follow these instructions.

To easily solve this potential problem, ALWAYS keep your keypad set to Universal Time or GMT if you will be using StarGPS. When you enter time into the GTO keypad, simply input the GMT as your local time, and keep the Daylight Savings setting at "0." Be sure that you put the correct UT date into the keypad as well! For example, for those of us in the US who might be setting up in the evening, UT may already be into "tomorrow," so tomorrow's date could be the correct entry. Likewise, an Australian setting up his or her keypad in the morning might need to remember that it is still "yesterday" in UT.

You can still have locations entered into the keypad, for quick setup at home without using StarGPS, but your time zone for ALL of your entered locations in the keypad must be set to "00" since the entered local time is UT. You will also need to remember that the keypad will now only show UT as the local time. This should not really pose a problem for astronomers, since we are quite used to converting local time to UT and vice versa. Accurate local time is not necessary in the keypad as long as the keypad can correctly calculate UT, which it does with StarGPS.

The instructions below will have you set your Auto-Connect to EXT. This means that StarGPS will be initializing your mount, not the keypad. You should be aware that there are additional parts of the initialization sequence that StarGPS cannot perform. Fortunately, the keypad supplies these parameters even in the External Startup Mode. These parameters include the tracking, guiding and slew rates; the backlash compensation settings for both RA and Dec; reticle brightness and focus speed; and the PEM state. Also, if you are not using StarGPS, you can still proceed through the start-up by pressing the menu button as instructed on the keypad's display, and then proceeding to enter a location number and resuming from park or polar aligning.

Finally, a word of caution if you are using planetarium software along with StarGPS and the GTO Keypad. DO NOT re-initialize the mount from any program on your PC, once you have initialized with the StarGPS / GTO Keypad combination. You can certainly use your favorite software, just like you normally would. You can change individual parameters that are part of the initialization, like backlash compensation or tracking rate, but DO NOT send time and location data from the computer, and do not do a full initialization. Doing so will overwrite the StarGPS data and may cause the same timing issues that were mentioned above. It also spoils the whole point of having a StarGPS in the first place.

Specific Instructions:

  1. Turn the GTO on.
  2. Configure the GTO for use with StarGPS - instructions are for keypad firmware v.4.xx:
    1. From the Main Menu select #2=Setup and press #3=KeyPad Options Menu.
    2. Press #1 to toggle to AUTO-CONNECT=EXT (external startup sequence).
    3. Press the Menu button to go back to the Setup menu.
    4. From the Setup Menu, press #1=Locations & Time.
    5. Press 1=Site Location Data.
    6. Enter a location number for which you have previously entered data (starting with location 1), and then press GO TO.
    7. Press the <PREV button to "back up" to the Time Zone line and change the time zone to zero. Press GO TO. The keypad will beep to confirm that it has been saved.
    8. Repeat steps d - g for ALL of your saved locations.
    9. From the Setup Menu, press #2=Set Date & Time.
    10. Enter the Universal Time (UT or GMT) in 24-hour format as your local time.
    11. Enter the correct UT date, keeping in mind that it may not necessarily be the same as the date in local time (see http://www.timeanddate.com/time/zones/).
    12. Set Daylight Savings to 0=Winter.
    13. Press GO TO to save.
    14. Press Menu to back out to the main menu.
  3. Turn off the power to the GTO for 10 to 15 seconds. You only need to do the above steps once before using StarGPS. The GTO will remember these settings for future use.
  4. Connect the GPS receiver to the supplied cable (you can leave these connected).
  5. Attach the DB9 connector to an RS232 port on the GTO.
  6. Turn on the GTO. The keypad should display the following message:
              External Startup
              Press MENU to cancel
              external startup.
    DO NOT PRESS MENU (unless you will not be using StarGPS).
  7. Plug the supplied cable into a 5 Volt USB power bank. The GPS LED should turn on.
  8. Wait until the GPS LED flashes once every 2 seconds. The GTO will display the Main Menu once it receives the date, time, latitude and longitude from the GPS.
  9. Disconnect the USB power bank (optional, but the GPS is no longer needed).
  10. Proceed as usual with the alignment process.

 

Celestron NexStar, NexStar+ or StarSense controlled mounts

Our new GPS-Celestron cable allows StarGPS to function like a Celestron SkySync which is compatible with all non‑GPS Celestron computerized telescopes. To begin with you need to configure the handset to look for a GPS. This is a one-time operation but will need to be repeated if you ever turn on the telescope without the GPS connected (Celestron designed it to work this way).

  1. Make sure that the telescope is turned off.
  2. Connect the GPS receiver to the AUX port on the telescope using the GPS-Celestron cable.
  3. If you do not have an AUX port (GT, AS-GT, CG5 mount) you can plug the included 6p6c jack splitter into the Hand Control jack and then plug the GPS-Celestron and hand control cable into the splitter.
    WARNING: Do not plug the GPS or splitter into the Autoguider port as this may damage the drive circuit.
  4. Turn on the telescope and then enable the GPS as follows:
  5. For NexStar/+ use Menu > Utilities > GPS on/off and then press ENTER to Turn GPS on.
    For StarSense use Menu > Time and Location > Time/Loc Source, select GPS Accessory and press ENTER and then BACK to accept the change.
  6. Turn off the telescope. The telescope will now utilize the GPS the next time that you turn it on.

NOTE: If you turn on the telescope without the GPS connected then the handset will automatically disable the GPS and you will need to repeat step 5 and 6.

Now that the handset is configured to use the GPS, you can continue as follows:

  1. Turn on the telescope and select the desired alignment method.
  2. The handset will wait for the GPS to get a location fix. It will then bypass the normal time and date prompts.
  3. Proceed with setup/alignment as usual.
  4. For NexStar you can use Menu > View Time-Site to see the date, time, latitude and longitude. The display will show “GPS Linking” until the GPS determines the location, which results in “GPS Linked”.
    For StarSense you can use Menu > Time and Location > View/Mod Location to display Lon & Lat, or View/Mod Time to display local time (alongside the time a “G” icon will flash until the GPS has a location fix).

NOTE: The local time displayed by the handset is based on the time zone and daylight saving settings. The mount will operate correctly regardless of these settings because all calculations are based on UTC. Local time is only used for display purposes and for manually inputting time. If you would like the correct local time please be sure that the handset time zone and daylight savings are correct.

NOTE: If you have an early 2007 model GPS-NX01 receiver with serial number 10001118 or lower you will need to update the GPS firmware. Please contact us for details.

WARNING: Connecting or disconnecting the GPS-Celestron cable from the AUX port with power on can potentially damage the cable and although this is unlikely, such damage is not covered under warranty. If you wish to save power after the GPS is referenced during alignment, please note that it is safe to disconnect the GPS module from the GPS-Celestron cable with power on, leaving the GPS-Celestron cable connected to your mount's AUX port.

 

Retired GPS-NexStar cable for use with older handsets

This cable is still available by special order but has been replaced by the GPS-Celestron cable (see above).

StarGPS-NX with a GPS-NexStar cable requires a NexStar (firmware version 2.3, 104.0 or 4.0+ as displayed using the hand control “Utilities: Version” menu item), a NexStar+ or a StarSense hand control with RS232 port (will not work with newer handsets that have a USB port). If you have a CGE Series mount you must use the "Utilities: RTC" menu item to disable use of the real time clock. This *must* be set to OFF, otherwise the CGE may get the time from the RTC instead of the GPS.

  1. Make sure the telescope is turned off.
  2. Connect the GPS receiver to the hand control and telescope using the supplied cable. The long lead connects to the RS232 port on the bottom of the hand control and can be routed up the center of the coiled cable if desired (it takes a few minutes to wind the coil around the long lead). The short lead plugs into an AUX port on the telescope to supply power to the GPS.
  3. If you do not have an AUX port (GT, AS-GT, CG5 mount) you can plug the included 6p6c splitter into the Hand Control jack on the mount and then plug the short lead and hand control cable into the splitter.
    WARNING: Do not plug the GPS or splitter into the Autoguider port as this may damage the drive circuit.
  4. Turn on the telescope.
  5. If using a StarSense hand control, if prompted to enter the time, quickly press the ENTER key 9 times to bypass the time, date, zone and DST settings (leaving you at the Set Align Start prompt).
  6. Wait until the GPS LED flashes once every 2 seconds.
  7. Proceed with setup/alignment as usual.
  8. For NexStar you can use the “View Time-Site” menu item to see the UTC date, time, latitude and longitude. For StarSense you can use Menu > Time and Location > View/Mod Location and then press the Option button to display Lon & Lat. The Time Zone is set to Universal Time with Standard Time.

IMPORTANT: If using a NexStar+ handset with GPS-NexStar cable please check the version of the HC firmware by selecting Menu > Utilities > Version. If your HC version is 5.28.xxxx or higher then you will need to update the handset firmware using the version posted at Archive_February_2016_2_5.25.4320.zip (refer to general instructions at Celestron Firmware Manager).

NOTE: The latest NexStar+ and Starsense handsets have a USB port instead of an RS232 port, but other than that they are identical to the older handsets. The GPS-NexStar cable will not work with a USB port.

NOTE: Mounts that support the CN16 GPS Accessory Kit (CGE, AS-GT, SLT, SE, iSeries) have a "Utilities: GPS" menu item that allows the CN16 GPS to be turned on or off. This menu item does not apply to the use of a StarGPS-NX with GPS-NexStar cable and will return "No GPS detected" (it looks for a CN16).

 

Losmandy Gemini Level 1 or 2

StarGPS-NX works with Gemini Level 1 or 2 by sending LX200 commands to the Gemini. This requires a power off/on cycle to reset the Gemini pointing model. Gemini Level 3 and 4 have the ability to detect a GPS receiver and don't require a power cycle, so we recommend upgrading your Gemini software.

  1. Make sure the Gemini is turned off.
  2. Connect the GPS receiver to the supplied cable (you can leave these connected).
  3. Plug one end of the cable into the Gemini RS232 port.
  4. Turn on the Gemini.
  5. Plug the other end of the cable into the Gemini power output.
  6. The GPS LED should turn on at this point.
  7. Wait until the GPS LED flashes once every 2 seconds.
  8. Disconnect the GPS from the Gemini.
  9. Turn off the Gemini, wait 5 seconds and then turn it back on.
  10. Select "Cold Start" if your observing location has moved by more than 500 km, if you changed the internal battery or did a "Reset Default".
  11. Proceed with setup/alignment as usual.
  12. Note that the local date and time are set to UTC (Coordinated Universal Time).

 

Losmandy Gemini Level 3 and higher

StarGPS-NX works with Gemini Level 3, V1.10 or newer firmware by sending standard GPS NMEA data to Gemini-1, Gemini-2 or Gemini-2 Mini at a rate of 4800 baud (GPS-NX01/02) or 9600 baud (GPS-NX03).

  1. Make sure the Gemini is turned off.
  2. If you have a Gemini-2 Mini you will need to plug the included DC power Y-cable into the 12-18VDC jack on the Mini and plug your power supply into one of these jacks. Note that the Y-cable serves to provide two DC power jacks (same as on the original Gemini-2).
  3. Connect the GPS receiver to the supplied cable (you can leave these connected).
  4. Plug one end of the cable into the Gemini RS232 port.
  5. Plug the other end of the cable into one of the Gemini DC power jacks.
  6. The GPS LED should turn on at this point.
  7. Wait until the LED flashes rapidly for 5 seconds (indicating that the GPS has switched to NMEA output). This will occur after 30 or 45 seconds.
  8. Wait until the GPS LED flashes once every 2 seconds.
  9. Turn on the Gemini.
  10. For Gemini-1 you will see a welcome message, the Gemini will look for a GPS receiver and then display "SRAM/RTC Updated" if it was successful.
  11. For Gemini-2 or Gemini-2 Mini the GPS data is accepted. However, the message "GPS Coordinates Updated" is only displayed if startup mode is "warm start" or "warm restart", or if you Query GPS from the hand controller Site menu. For more details see http://www.gemini-2.com/StarGPS.html
  12. Disconnect the GPS from the Gemini.
  13. Proceed with setup/alignment as usual.

NOTE: if the GPS is not recognized please try setting the Gemini GPS serial port speed to 9600 baud since the factory default setting on the Gemini GPS serial port is 4800 baud.

 

Autostar 495/497/497EP/Audiostar controlled telescopes (ETX/LXD/LX90/LX80/LT/LX65/LX85):

WARNING: The original LX65 and LX85 mounts have reversed polarity AUX ports and require a GPS-ASTARX cable. This cable is identical to the GPS-ASTAR cable except that there is no AUX label on the short lead and the power lines are reversed. Using the incorrect cable will cause damage to your mount. Meade has corrected the AUX port on newer LX65 mounts as indicated by a white sticker on the battery compartment, see below. If you have an LX65 with white sticker then you must use a GPS-ASTAR cable.

  1. For LX90GPS/SC/ACF you must disable the built-in GPS via Select Item: Utilities > GPS > OFF.
  2. Turn the telescope off.
  3. Connect the GPS receiver to the handset and telescope using the GPS-ASTAR cable. The long lead connects to the RS232 port on the bottom of the handset and can optionally be routed up the center of the coiled handset cable (wind the coil around the long lead). The short lead plugs into an AUX port on the telescope to supply power to the GPS. WARNING: DO NOT REVERSE THE CABLE CONNECTIONS since this can cause damage to the telescope or handset.
  4. Turn on the telescope and within 15 to 30 seconds the handset displays “Please wait…”.
  5. The current time in UTC is shown while the GPS calculates your location.
  6. The message “Finishing…” is followed by the Align: Easy/Auto menu prompt (or with LNT, Select: Object).
  7. Press the ENTER key to continue with alignment (or with LNT, first navigate to Align: Auto).
  8. You can press and hold the MODE key for two seconds and then use the up/down scroll keys to view the UTC date, time, latitude and longitude. The Time Zone is set to zero and Daylight Savings is set to NO.

If your handset does not display the messages in steps 4 to 6 then use the following instead:

  1. Turn on the telescope and complete these steps within 30 seconds.
    1. If you are asked to “Press 0 to Align or MODE for Menu” then press the MODE key.
    2. If you see “Align: Automatic” proceed to step 5 below, otherwise:
    3. Use the handset keypad to skip past any messages or date/time prompts and reach the “Align: Easy” prompt (make sure to select NO for Daylight Savings if prompted).
  2. Wait until the GPS LED flashes once every 2 seconds.

IMPORTANT: Please check the software version of your handset by watching the top right corner of the display just after turning on the power. The following original Meade versions have a bug in at least one LX200 command such as "set latitude" or "set date": Autostar 497 (27, 30, 35, 40, 41, 42), Autostar 497EP (all versions), Audiostar (A4S1 and all versions prior to A3S4). If your handset displays any of these version numbers (eg. 40E, 5EC1) you must update your handset using StarPatch. With the free trial version of StarPatch you must uncheck the "GPS Setup" option before doing an "Update Handset".

 

Meade LX200 Classic

  1. Turn the telescope off.
  2. Connect the GPS receiver to the GPS-LX200 cable (you can leave these connected).
  3. Plug the other end of the cable into the RS232 port on the LX200 control panel.
  4. Turn on the telescope and wait until the GPS LED flashes once every 2 seconds.
  5. Unplug the GPS from the RS232 port.
  6. Proceed with setup/alignment as usual.

Note: if you are using an upgraded LX200 Classic controlled by a 497/497EP Autostar or Audiostar then we recommend the StarGPS Package.

 

Meade LX200GPS, LX200R, LX200ACF, LX400ACF, RCX400:

A GPS-NX02 with firmware version 1.1 and newer or a GPS-NX03 is required. This can be used to replace the built-in GPS in any of the above models and is useful in cases where the internal GPS is not operating properly. For example, an external GPS-NX03 can be mounted outside an observatory dome and connected via a PS2 keyboard extension cable of up to 50 ft (15m).

  1. Disable the built-in GPS via Select Item: Setup > Telescope > GPS Alignment > OFF.
  2. Turn the telescope off.
  3. Connect the GPS receiver to the GPS-LX200 cable (you can leave these connected).
  4. Plug the other end of the cable into an RS232 port on the control panel.
  5. Turn on the telescope and within 45 seconds the handset displays “Please wait…”.
  6. The current time in UTC is shown while the GPS calculates your location.
  7. The message “Finishing…” is followed by the Select Item: Object menu prompt.
  8. Proceed to Select Item: Setup > Align to continue with alignment.
  9. You can press and hold the MODE key for two seconds and then use the up/down scroll keys to view the UTC date, time, latitude and longitude. The Time Zone is set to zero and Daylight Savings is set to NO.

For remote operation, if the telescope will be unparked using the :I# command versus a full power off-on then you’ll need to update the Autostar II firmware using StarPatch and selecting the [Allow StarGPS Reboot on “Soft”boot] patch. The free trial version of StarPatch can be used as described at http://www.stargps.ca/manual.htm#starpatch

 

Synta (Orion Atlas/Sirius GoTo, SkyWatcher SynScan)

StarGPS-NX requires a hand control with firmware version 3.10+ or AZ 3.03+

  1. Make sure the telescope is turned off.
  2. Connect the GPS receiver to the GPS-Synta cable (you can leave these connected).
  3. Plug the other end of the cable into the multi-purpose port (the 6 pin port) on the hand control.
  4. Turn on the telescope.
  5. Use the ENTER key to skip ahead until the hand control displays "Initializing…".
  6. Once the GPS is recognized you are prompted for time zone and daylight saving (these are only used to calculate the local time display).
  7. The display shows "GPS Fixing…" until a satellite fix is obtained. The hand control then bypasses the normal location, time zone, date, time and daylight saving prompts.
  8. Proceed with setup/alignment as usual.
  9. You can use the "Utility Func. > GPS" menu item to view detailed GPS information.

 

USB (PC connected)

If your telescope is connected to a Windows PC you may choose to connect the GPS receiver to the PC and have it forward data from the GPS to your telescope as described below. This has the advantage of using your existing PC-to-Telescope serial cable. This procedure will not work with a Synta handset, eg. SynScan.

  1. Download the Redirect utility program from http://www.stargps.ca/pub/redirect.exe
  2. Make sure the telescope is turned off.
  3. Connect the telescope to the PC (using your existing PC-to-Telescope cable).
  4. Plug the GPS-USB cable into the PC (without the GPS attached).
  5. Run redirect.exe
  6. Select the GPS COM port and a baud rate of 4800/9600 (Gemini Level 3+) or 9600 (all others).
  7. Select the Telescope COM port and the same baud rate as above.
  8. If using a Vixen StarBook, select the "IP" checkbox and enter the IP address of the StarBook (this can be found using the "About StarBook" menu item).
  9. With Gemini Level 3+, plug the GPS into the GPS-USB cable, wait until the GPS LED flashes once every 2 seconds, press "Connect", turn on the Gemini and go to step 13).
  10. Turn on the telescope.
  11. Press "Connect" to establish the connection between the telescope and GPS.
  12. Plug the GPS into the GPS-USB cable.
  13. Follow the normal StarGPS-NX instructions subsequent to "Turn on the telescope".
  14. Press "Exit" to disconnect and exit from redirect.exe
  15. Continue as usual with your PC and planetarium software.

 

Troubleshooting StarGPS-NX

GPS results are displayed but not saved. This occurs if you have updated the handset using the free trial version of StarPatch. To correct the problem you must uncheck the "GPS Setup" patch and then do an "Update Handset". Otherwise, a registered copy of StarPatch is required to use "GPS Setup" with a GPS receiver.

GPS LED does not light up. Turn the telescope off. Check the GPS cable connections and try again. This problem indicates a faulty GPS receiver or connecting cable (assuming that the telescope power supply is working).

GPS LED lights up but does not blink within 30 or 45 seconds, then rapidly blinks for 5 seconds. Turn the telescope off. Check the GPS cable connections and try again. This problem indicates a faulty connecting cable. The GPS is not receiving a response from the telescope/controller. The rapid blinking indicates that the GPS is switching to NMEA output - this is the normal operating mode for use with a Losmandy Gemini Level 3 or 4.

GPS LED lights up but does not blink or blinks "short-off" once per second. This indicates that the GPS is unable to get a satellite location fix. This can happen indoors and can also occur outdoors if you do not have a fairly open view of the sky (e.g. too many obstructions). Try leaving the GPS turned on for at least twenty minutes or move to a better location.

GPS LED flashes once every 2 seconds but the telescope settings are wrong. This problem can occur when using a Meade Autostar/Audiostar with no LNT. You must complete steps 4a thru 4c quickly or the GPS will finish setting the telescope before you skip past the date, time and daylight savings prompts. In this case the GPS results get overridden by the default date and time.

Meade handset display goes blank when the GPS blinks once every two seconds. Press the "0" key to turn the display back on (any key will do but "0" is the safest). This problem only occurs if the GPS time (UTC) exceeds the handset time. This happens because the handset automatically turns the display OFF if the keypad is not used for 10 minutes. When the GPS sets the time to anything more than 10 minutes ahead, the handset mistakenly thinks that the keypad has not been used so it turns the display OFF - a minor annoyance.

Meade Autostar latitude is not being set. This problem is due to a bug in Meade software versions 27 and 30. The software version is displayed by the Autostar just after you turn on the power. To correct this problem you will need to update the Autostar software by using the free trial version of StarPatch or the Meade ASU.

Meade Autostar alignment fails (motor stops or extended slewing). This problem is due to a bug in Meade software versions 35, 40, 41 and 42. The software version is displayed by the Autostar just after you turn on the power. To correct this problem you will need to update the Autostar software by using the free trial version of StarPatch or the Meade ASU.

NexStar+ handset is not accepting GPS data. This problem is indicated when the GPS LED displays a short on-blink once every second but never transitions to a short on-blink every two seconds. The problem occurs with handset firmware versions 5.28.xxxx and later. This can be corrected by updating the handset using the version posted at Archive_February_2016_2_5.25.4320.zip (refer to general instructions at Celestron Firmware Manager).

Rapidly blinking GPS LED when used with StarSense handset. This problem will occur with all GPS-NX01 and older GPS-NX02 receivers produced prior to the introduction of StarSense. The problem can be corrected by returning the GPS to us for a firmware update - contact us for details.

 

Using StarGPS

This section describes how to use StarGPS and its components. You may also wish to download a copy of the "StarGPS Quick Start Instructions" which are in PDF format.

StarPatch Setup and Use

The free trial version of StarPatch can be used to correct for the GPS Week Number Roll Over problem by updating your 497/497EP, Audiostar or Autostar II. If you find the trial version useful please consider making a donation of $5 by clicking on the button below.

StarPatch allows you to update your Autostar 497/497EP, Audiostar or Autostar II handset with new features (patches) along with the latest software from Meade. The GPS Setup patch is not available for Autostar II. The Autostar has one serial port which allows it to be connected to a PC for software updates. Follow these steps to update your Autostar:

  1. Download and run the installation program from http://www.stargps.ca/pub/setupSP.exe NOTE: Windows may indicate "Unknown Publisher" when you attempt to run the installation program since it is not digitally signed. Please disregard this message.
  2. Once StarPatch is installed on your PC you can click on the Windows "Start" button, go to the "Programs" menu and select "StarPatch".
  3. If desired, use the "Options: Handset type" menu (default is Autostar 497).
  4. If desired, use the "Options: Language" menu (default is English).
  5. Use the "File: Get Updates…" menu to download the latest handset software and patches (based on the language and handset selections in step 3 and 4).
  6. If you have an LX80, LX65 or LX85 you will need to download and extract PatchAUA4S4v04.spf and BuildAUA4S4.rom to the StarPatch program folder “C:\Program Files\PixSoft\StarPatch\” as listed at http://www.stargps.ca/downloads.htm
  7. Make sure the telescope is turned off.
  8. For the Autostar 497/497EP or Audiostar (eg. ETX90) connect your PC to the handset using a USB-ASTAR cable (or Meade #505 cable) as shown below.

  1. For the Autostar II (eg. LX200GPS) connect your PC to the mount using a Meade #507 cable. Plug the 9-pin connector into the serial port on your computer. Plug the 6-pin modular connector into the RS232 port immediately to the right of the handbox socket on the control panel.

  1. Turn the telescope on and wait until the handset is ready (you will hear a beep).
  2. If you have a StarPatch software registration key, use the "File: Register..." menu to enter the key. Each key allows one 497/497EP/Audiostar to be registered for use with a GPS receiver. An unregistered version of StarPatch will install a trial version of the GPS Setup patch. The StarPatch window title will indicate the registration status as follows:
  1. Trial - not registered (free for use trial version).
  2. Registered - successfully registered: will allow one handset to be GPS enabled.
  3. Registered Handset - one handset was successfully registered and GPS enabled (this is done in step #15 if the GPS Setup patch is selected
  1. If you have a telescope with a built-in GPS and want to correct the GPS Week Number Roll Over problem then deselect "GPS Setup" (Autostar 497/497EP or Audiostar) and select "Fix GPS Rollover Bug".
  2. Press the "Update Handset" button. This will guide you through the update process. StarPatch will select the latest patch file if none has been chosen. Advanced users can pre-select the software version and features they want. The update process performs several steps to confirm:
  1. The PC can communicate with the handset (the cable connection is working).
  2. A valid StarPatch File (SPF) has been selected (the latest file will be selected if none is specified). Each SPF file contains additional software features such as the GPS Setup capability. These features are known as software "patches" because they get "patched" or added into the handset software (ROM file).
  3. The corresponding ROM file is present. Each ROM file contains the original handset software supplied by Meade (with no patches) as described at http://www.meade.com/support/auto.html
  1. Press the "Yes" button in response to "Do you want to continue with the update?"
  2. If you are updating an Autostar or Audiostar with a new registration key and have selected the GPS Setup patch then you will be asked if you want this connected handset to be registered for use with a GPS receiver. Press the "Yes" button if you want to register this handset.
  3. Wait for the update to complete ("Update completed" message) and press the "OK" button. If you selected "Yes" in step #15 then a successful update with a registration key will change the StarPatch window title to read "Registered Handset" as described in step #11c.
  4. Press the "Exit" button to exit from StarPatch.

NOTE: When you next use your telescope you should do a Setup > RESET to guarantee proper initialization of the handset. You'll have to re-enter your City, re-CALIBRATE and re-TRAIN for best operation. If you are not familiar with this process you can learn more by visiting http://www.weasner.com/etx/techtips/etx_tuneup2.html

NOTE: If your handset already had a recent version of software installed prior to using StarPatch, you may not need to reset, re-calibrate and re-train. In this case you might want to try out the telescope and skip those steps if everything works.

NOTE: Any user objects (comets, tours, etc) that were downloaded to the handset (using the Meade Autostar Update program) will remain untouched by StarPatch.

 

Menu Items

File

Get Updates...
Connects to the StarGPS web site and lists the latest patch and ROM files that are available (based on the current language and handset type). Determines which files you need (if any) and downloads them.

Create ROM
Creates a ROM file based on the current patch file settings. The file is named according to the patch version number and is placed in the StarPatch folder (see installation notes).

Print...
Prints the current patch file documentation to StarPatchFile.txt and opens this file which can then be printed.

Register...
Connects to the StarGPS web site to register your copy of StarPatch (requires a software registration key). This enables all the program features and allows the GPS Setup patch to be installed to one Autostar or Audiostar. Additional handset registration keys can be entered here if you need to install the GPS Setup patch to a second or third Autostar.

Exit
Exits the StarPatch program.

Options

COM port...
Allows you to select which COM port the handset is connected to (otherwise this will automatically be determined when you use the "Update Handset" button).

Baud rate >
Allows you to select the COM port baud rate to be used by "Update Handset". The maximum rate is 115200 (Autostar/Audiostar) or 57600 (Autostar II).

Handset type >
Allows you to select your handset type (default is Autostar 497).

Language >
Allows you to select English or German language patches (default is English).

SmartLoad
Allows you to enable or disable the SmartLoad feature (default is enabled). SmartLoad can achieve faster updates by just sending data that has changed since the previous update. You can disable SmartLoad if you want to force a complete update.

Help

Instructions
Displays basic help information.

User Manual
Opens this installed copy of the User Manual.

StarPatch Home Page
Opens http://www.stargps.ca

Meade Home Page
Opens http://www.meade.com

Weasner's ETX Site
Opens http://www.weasner.com/etx

About StarPatch...
Displays the StarPatch version number and copyright information.

 

Installation Notes

All program related files are placed in the StarPatch folder which defaults to C:\Program Files\PixSoft\StarPatch.  The distribution files include:

  1. StarPatch.exe - the program
  2. StarPatch.ini - default program settings
  3. License.txt - the software license agreement
  4. Readme.txt - additional information
  5. manual.htm - a copy of this manual

Use the StarPatch "File: Get Updates" menu item to copy the latest SPF (StarPatch files) and ROM files (Meade Autostar software) to the StarPatch folder. The filenames indicate the handset type and software version as in:

  1. PatchEP5Ce1v06.spf - patch file version 5Ce1v06 for Autostar 497EP (English)
  2. Patch34CA.spf - patch file version 34CA for Autostar 497 (English)
  3. PatchG32HA.spf - patch file version 32HA for Autostar 497 (German)
  4. PatchLX42gg3.spf - patch file version 4.2g for Autostar II (English)
  5. BuildEP5CE1.rom - Autostar 497EP software version 5CE1
  6. Build34Ec.rom - Autostar 497 software version 34Ec
  7. BuildLX4.2g.rom - Autostar II software version 4.2g

StarPatch will also look for ROM files that have already been downloaded using the Meade ASU.  If you need older patch or ROM files you can find them here:

http://www.stargps.ca/downloads.htm - patch files
http://www.weasner.com/etx/autostar/as_archive/downloads.html - Autostar ROM files
http://www.californiastars.net/lx200gps/tips.html - Autostar II ROM files

  

GPS Setup and Use

These steps assume that you have already used StarPatch to update the handset software so that GPS data will be recognized. You can confirm this by turning on the handset and using the keypad to skip the sun "WARNING" and the "Getting Started" message. At this point you would normally see the "Enter Date:" prompt. If the GPS Setup patch has been installed you will instead see the "Checking for GPS" message. This message will appear for 3 seconds and then revert to the "Enter Date:" prompt if there is no GPS connected.

 

Creating a GPS Site

This step is not required but is recommended (it looks better). It describes how to setup a "GPS Site" name rather than using a fixed "city name".

The GPS Setup patch uses GPS data to automatically update the handset time, date and current site latitude and longitude. For example, if the you had previously chosen "Seattle" as the current site then the GPS Setup patch would update the latitude and longitude of "Seattle". This is probably fine since you are likely to do most of your observing in that area. However, you might want to change the site name to something more generic like "GPS Site". You can do this as follows:

  1. Use the MODE key to position to the "Setup:" menu
  2. Select "Site" and press ENTER
  3. Select "Edit" and press ENTER
  4. Select "Name" and press ENTER
  5. Enter "GPS Site" and press ENTER

 

Setting the Time Zone

GPS receivers measure time in UTC (Coordinated Universal Time). The handset converts UTC to local time by looking at the time zone offset for the current site and the DST (daylight savings time) setting. The conversion formula is:

local time = UTC + time zone offset + DST

where DST = 0 (standard time) or DST = 1 (daylight savings time). For example, if you selected "Seattle" as the current site then the handset would set the time zone offset to -8.0 for Pacific Standard Time (PST). If you selected Daylight Savings = Yes then it would add an hour and use an offset of -7.0 for Pacific Daylight Time (PDT). So 10:00 UTC converts to 02:00 PST or 03:00 PDT.

The handset will work properly even if the time zone offset and DST settings are incorrect. However, it will display the incorrect local time. In order for the handset to convert the GPS time from UTC to local time you need to set the time zone offset and DST. This can be done as follows:

  1. Turn on the telescope (with no GPS) and press the proper keys to skip ahead until you see the "Daylight Savings>" prompt.
  2. Select "Yes" or "No" (answer Yes if you are -currently- in your "Summer Time" advanced-clock situation, answer No otherwise) and then press "Enter".
  3. Use the MODE key to position to the "Setup:" menu
  4. Select "Site" and press ENTER
  5. Select "Edit" and press ENTER
  6. Select "Time Zone" and press ENTER
  7. Enter the standard time zone offset for your location (see below links)

NOTE: If you prefer to have the handset display UTC as the "local time" you can simply set the time zone offset to 0.0 and Daylight Savings to "No". The advantage of doing this is that you will never need to change these settings, no matter what time zone you move to.

For more information on UTC and time zones, you can visit:

https://www.time.gov/ - find your US time zone
https://www.timeanddate.com/ - find your city and time zone
https://www.timeanddate.com/time/zones/ - world wide time zones

 

Using the GPS Receiver

The GPS Setup patch allows an Autostar 497/497EP or Audiostar to accept NMEA-0183 v2.0+ GPS data. The GPS date, time, latitude and longitude are used to initialize the handset. To use the GPS receiver do the following:

WARNING: The original LX65 and LX85 mounts have reversed polarity AUX ports and require a GPS-ASTARX cable. This cable is identical to the GPS-ASTAR cable except that there is no AUX label on the short lead and the power lines are reversed. Using the incorrect cable will cause damage to your mount. Meade has corrected the AUX port on newer LX65 mounts as indicated by a white sticker on the battery compartment, see below. If you have an LX65 with white sticker then you must use a GPS-ASTAR cable.

  1. Make sure the telescope is turned off.
  2. Connect the GPS-ASTAR cable as shown below:

  

  1. Plug the short cable (5 cm, 2") into an AUX port on the telescope. This will provide power to the GPS receiver.
  2. Plug the round PS/2 connector into the GPS receiver cable. The GPS can then be placed anywhere with a good view of the sky. Make sure the receiver is fairly level and facing upward. You may wish to use the included velcro tape to attach the GPS on top of the telescope (as shown).
  3. Plug the long cable (60 cm, 24") into the handset. This will route data from the GPS receiver to the handset. You may wish to permanently route this cable up the center of the coiled handset cord (see above photo). Simply wind the coiled cord around the cable (it takes a couple minutes to do this). WARNING: DO NOT REVERSE THE CABLE CONNECTIONS since this can cause damage to the telescope or handset.

  1. Turn on the telescope. This will supply power to the GPS and handset.
  2. Following the "Welcome to AUTOSTAR or AUDIOSTAR" message, the display will show:

    If this message is not displayed please refer to "StarPatch Setup and Use".

  3. When the handset recognizes GPS data it will display the following:


  1. GPS time (hours : minutes : seconds in UTC). The GPS time may initially be incorrect but will adjust itself once a GPS satellite signal is detected.
  2. Number of satellites (top right) shows how many satellites have been detected with a SNR (signal-to-noise ratio) of at least 20 dB. Typical signal levels range from 25 to 50 dB but must usually be at least 30 dB for use in determining the location.
  3. Satellites in view (bottom left) shows a one character bar graph for each satellite. The bar graph corresponds to the SNR dB value as follows:
    • 00 – 19 = dot
    • 20 – 24 = 1 bar
    • 25 – 29 = 2 bars
    • 30 – 34 = 3 bars
    • 35 – 39 = 4 bars
    • 40 – 44 = 5 bars
    • 45 – 49 = 6 bars
    • 50 – 99 = 7 bars
  4. Average SNR (bottom right) shows a one character bar graph alongside the computed average of all SNRs of at least 20 dB.
  1. Take note of the UTC time and how it compares to your local time. This step will later help you to confirm that your time zone offset is properly set.
  2. When the GPS obtains a fix (determines the location based on at least 3 satellites) the handset will beep and display the date, latitude and longitude for 5 seconds as in:

    If you have a registered handset then the handset time, date and current site latitude and longitude will be set. It usually takes lee than one minute to obtain a fix but this can vary depending on how many satellites are in view and their signal strengths. In general a more open sky gives better results. If there are too many obstructions it may not be possible to get a fix. For more information about the Global Positioning System and how it works you can visit http://www.garmin.com/aboutGPS/.

  3. Unplug the GPS receiver since it is no longer needed (plus this saves power).  You can begin by pulling the AUX plug or disconnecting the PS/2 connector (either of these will cut the power).
  4. Press the ENTER key to proceed from the "Align:" prompt.
  5. You can confirm that the time zone offset is correct by checking the local time computed by the handset as follows:
  1. Press and hold the MODE key for at least 2 seconds.
  2. Press the up or down scroll key next to the "?" until the "Time:" is displayed.
  3. If the local time is incorrect then you might want to adjust the time zone offset and return to step #1 (also refer to "Setting the Timezone").

 

Using a Handheld GPS Receiver

If you already own a handheld GPS receiver you may be able to use it with your Autostar 497/497EP or Audiostar handset. Some GPS receivers such as the eTrex Vista C provide a USB serial port that is not compatible with the handset RS232 serial port. If your GPS has a USB port then it cannot be used with the handset. Any GPS receiver that includes a standard RS232 serial port can be used as described below. In this case you need the following items:

  1. StarPatch software registration key (to install the GPS Setup patch).
  2. USB-ASTAR cable or Meade #505 cable (for use with StarPatch).
  3. GPS adapter cable (or equivalent) to connect your GPS output to the handset RS232 serial port. Please be sure that you order the correct cable for your GPS receiver (if it is listed).

The GPS Setup patch allows the handset to use NMEA-0183 version 2.0+ GPS data to set the date, time, latitude and longitude. The GPS receiver must be connected to the handset serial port and must output NMEA $GPRMC data. Satellite information and signal strength are displayed by the handset if NMEA $GPGSV data is available. In order for your GPS receiver to work it must output $GPRMC data.

If you have a Garmin or Magellan GPS receiver you may be able to use a GPS adapter cable which allows you to directly connect your GPS to the handset. Otherwise you will need a serial data cable. Many GPS receivers include such a cable or list it as an optional item. These cables normally have a female DB9 connector which is designed to plug into the serial port on a PC. You can extend this cable to connect to the handset instead of the PC as follows:

  1. Make sure your GPS receiver is properly configured to output NMEA $GPRMC and $GPGSV data at a rate of 4800 or 9600 baud with no parity, 8 data bits and 1 stop bit. Refer to your GPS User’s Manual to configure the NMEA output settings. If your GPS receiver is not configured properly it may output data that switches the handset into download mode - if this happens you will need to reprogram the handset using StarPatch.
  2. Connect the GPS serial cable to the GPS receiver.
  3. Connect a DB9 male-to-male "Null Modem" adapter to the GPS serial data cable.
  4. Connect a Meade #505 cable to the adapter.
  5. Connect the Meade #505 cable to the handset.

NOTE: Most handheld GPS receivers such as the eTrex do not output $GPRMC data until they obtain a valid fix. In this case the handset will display "00:00:00 UTC" until a valid fix is obtained.

 

Using a Bluetooth or USB connected GPS Receiver

A Bluetooth or USB connected GPS receiver can be used along with a Windows laptop to forward data from the GPS to your telescope as described below:

  1. Download the Redirect utility program from http://www.stargps.ca/pub/redirect.exe
  2. Make sure the telescope is turned off.
  3. Turn on the Bluetooth GPS or plug the USB GPS into the laptop.
  4. Connect the handset to the laptop (using a USB-ASTAR or Meade 505 cable).
  5. Run redirect.exe
  6. Select the GPS COM port and baud rate (likely 9600 baud, sometimes 4800).
  7. Select the handset COM port and baud rate (9600 baud).
  8. Press "Connect" and you should see GPS data being displayed, something like: $GPGSA,A,3,11,09,20,17,,,,,,,,,3.6,2.6,2.5*39 $GPGSV,3,1,09,17,86,292,33,07,71,257,00,28,54,115,00,24,53,141,00*78 $GPGSV,3,2,09,09,29,309,36,11,24,051,40,04,23,186,00,20,14,090,34*79 $GPGSV,3,3,09,08,12,171,00*4C $GPRMC,171100.456,A,4952.8654,N,09717.0897,W,0.19,21.00,120106,,*24
  9. Turn on the telescope (the handset will output an "X").
  10. Watch the handset as it displays the incoming GPS data and wait until it beeps, indicating that the GPS satellite fix has been obtained.
  11. Press "Exit" to disconnect and exit from redirect.exe
  12. Continue as usual with AutoStarSuite or any planetarium program.

 

Troubleshooting StarGPS

StarPatch "Get Updates Failed (socket 10035)". Download and install the latest version of StarPatch and try again.

StarPatch "The required ROM file could not be found". Use "File: Get Updates..." to automatically download the required file.

StarPatch "Unable to connect to handset". Check that the cable connects the handset to a working COM port on the PC. To see a list of available COM ports use the "Options: COM port" menu (ports that are already being used by other programs are not listed). You can test the PC->handset communications by using these steps: http://www.weasner.com/etx/autostar/as_testing.html

Common problems include:1) the COM port is already being used by another program such as ActiveSync or Palm Pilot HotSync Manager with WinXP (check for icons in the system tray and disable these programs). 2) the wrong COM port number is selected (StarPatch will search COM1 thru COM255). 3) a USB-to-Serial adapter is being used but its USB driver has not been installed. 4) a bad cable or loose connection (which the above test page may catch).

StarPatch "Update Handset" says "Invalid R parameter...RBAD0000000". This error indicates that you are using StarPatch 1.4 or an earlier version that cannot process the selected patch file. The solution is to download and install the latest version of StarPatch.

StarPatch "Update Handset" failed. Check the cable connection and use the "Options: Baud rate" menu to select a slower baud rate like 57600 (some older handsets will not work at 115200 baud). Try again as described in the "failed" message dialog (see next problem).

The handset appears to be dead (no display) or displays garbage. This is usually the result of an incomplete update. You must do a "safe load" as follows:1) turn the telescope (handset) power OFF. 2) hold down the ENTER key and the SCROLL-DOWN key (next to "?") at the same time while turning the power ON. The handset will display "FLASH LOAD READY" (495/497) or "DownLoad Mode" (497EP/Audiostar). 3) click on "Update Handset".

GPS results are displayed but not saved. This indicates that you have installed a Trial Version of the GPS Setup patch. You must register StarPatch first and then do an "Update Handset". The StarPatch window title will indicate: 1) Trial (you need to use the "File: Register" menu). 2) Registered (you need to do an "Update Handset"). 3) Registered Handset (the registration key was already used or installed on another PC). An additional handset registration key is needed to GPS-enable a second or third handset.

The handset says "GPS not found". Turn the telescope off. Check the GPS cable connections and try again. This problem may indicate a faulty GPS receiver or cable. It may also occur if the GPS output settings are incorrect (or have been changed from the required NMEA settings). Please contact us with details, including how many ">" characters are displayed below the "Checking for GPS" message as in: >   (no input data = bad connection, also refer to "GPS LED does not light up") >>   (9600 baud data was present = incorrect NMEA settings) >>>   (data at some other baud rate = incorrect NMEA settings)

GPS LED does not light up. Turn the telescope off. Check the GPS cable connections and try again. This problem indicates a faulty GPS receiver or connecting cable (assuming that the telescope power supply is working).

GPS LED lights up but does not blink after several minutes. This indicates that the GPS is unable to get a satellite fix. This can happen indoors and can also occur outdoors if you do not have a fairly open view of the sky (e.g. too many obstructions).

 

Using the USB-ASTAR cable

The USB-ASTAR cable is used to connect a PC to a Meade 497 Autostar or Audiostar handset. This replaces the original PC-ASTAR or Meade #505 cable which would often require the purchase and use of an additional USB-to-Serial adapter cable since most PCs no longer have an RS232 serial port. The USB-ASTAR cable allows a USB port to operate as a virtual COM port for use with StarPatch as follows:

  1. Plug the USB-ASTAR cable into a USB port on your PC.
  2. Wait for Windows to locate and install the appropriate device driver. You may see notifications such as:
    1. Setting up a device: We’re setting up FT231X USB UART.
    2. Device is ready: USB Serial Port (COM4).
  3. Notice that the second message indicates which COM port has been assigned, in this case COM4.
  4. StarPatch can automatically determine which COM port is connected to a Meade handset.

Troubleshooting
If StarPatch finds no COM ports then the device driver for the USB-ASTAR cable is not installed or operating properly. Normally Windows will automatically detect and install the driver. Most PCs have no COM ports. The USB-ASTAR cable plugs into a USB port and creates a virtual COM port by installing a device driver.

At the bottom left in the Windows 10 search bar type "device manager" and hit Enter. An alternative method is to click on the Settings icon (bottom left) and search for “device manager”. In older versions of Windows you can go to Settings > Control Panel > System > Device Manager. Any of these will bring up the Device Manager. Under "Other devices" you will likely see "FT231X USB UART". Right click on that and select "Update driver" and then "Search automatically". This should locate and install the proper device driver. After this you should see "USB Serial Port (COM4)” listed under "Ports (COM & LPT)" instead of "Other devices". Note that the device name indicates the assigned COM Port number, in this case COM4.

It is also possible that the "USB Serial Port" device is already listed under “Ports (COM & LPT)”. In this case you can also right click on it to update the device driver as described above. You might also try uninstalling the device and driver, unplugging the USB-ASTAR cable and then plugging it back in. The recommended device driver can be found at https://www.ftdichip.com/Drivers/VCP.htm

NOTE: For running Windows 11 using Parallels on a Mac M1, please use the following driver:
https://ftdichip.com/wp-content/uploads/2022/02/CDM-v2.12.36.4-for-ARM64-Signed-Distributable.zip

These driver files must be placed on the C: partition (container drive) of your Parallels setup and manually installed. When you're in the Windows container and using Edge (or other browser) and download files they DO NOT end up directly in the container drive (i.e. C: drive). If you try to install a driver that is not on the "C: drive" Windows complains and fails. Manually moving the drivers to the C: drive within the Parallels container and then manually installing works.

NOTE: Older USB-ASTAR cables use the "Silicon Labs CP210x USB to UART Bridge" chipset as found at https://www.silabs.com/products/development-tools/software/usb-to-uart-bridge-vcp-drivers

 

Using the GPS-USB cable

The GPS-USB cable is used to connect any StarGPS to a PC. The cable plugs into a USB port and creates a virtual COM port for use with any PC software. You can then configure your PC software to communicate with the GPS via that COM port. The StarGPS will automatically switch to NMEA output 30 seconds (GPS-NX01) or 45 seconds (GPS-NX02 and GPS-NX03) after power-on if a telescope is not detected.

  1. Plug the GPS-USB cable into your PC and make note of the assigned COM port number. Windows Update will use your internet connection to locate and install the appropriate driver. If necessary you can also download and install the PL2303 driver from
    https://www.prolific.com.tw/UserFiles/files/PL23XX_Prolific_DriverInstaller_v408.zip
    This allows the USB port to operate as a virtual COM port.
  2. Connect the GPS to the GPS-USB cable.
  3. Verify that the GPS LED is turned on (it should be getting power from the PC).
  4. Wait 30 or 45 seconds until the GPS LED flashes rapidly to indicate that it has switched to NMEA output.
  5. Run your PC software, for example the GPSView program from http://www.stargps.ca/pub/GPSView.exe.
  6. Select the assigned COM port and 4800 baud (GPS-NX01/02) or 9600 baud (GPS-NX03)
  7. Click on the "Open Port" button (in our GPSView example).
  8. You should see NMEA messages being displayed by GPSView.

To use the GPS-USB cable in conjunction with your PC and telescope please refer to either the StarGPS-NX USB instructions or the StarGPS USB instructions.


GPS Week Number Roll Over

The 10-bit GPS week number roll over issue is and will be a problem for many GPS receivers. The calculation of the current date is based in part on a 10-bit week number which ranges from 0 to 1023. On April 6, 2019 the week number was 1023 which then rolled over to zero on April 7, 2019. On that day some GPS receivers (like the GPS-NX01) returned a date of August 22, 1999 which represents the first day of week zero. Most telescope mounts then interpret "99" as the year 2099. In any case a GPS receiver will always return the correct time, latitude and longitude.

If you are using a GPS that returns an older date there are a few options to correct this for use with your telescope:

  1. Use the telescope handset to manually input the correct date (no kidding).
  2. Update the telescope/handset firmware (this is the easiest solution). Celestron and others are doing this by adding 1024 weeks to any dates that are older than the firmware. StarPatch does the same for Meade.
  3. Update the GPS firmware (if possible).

Customers who own a GPS-NX01 can obtain a firmware update by sending just the receiver to our address on the About Page. Please list it as "Telescope accessory" with a value of $15 USD otherwise Canada Customs may want to collect duty and taxes as it crosses into Canada. There is a $15 charge to reprogram the GPS and then $10 for return shipping. An updated GPS-NX01 will return the correct date until the next roll over on November 21, 2038.

 
GPS-NX01 firmware update
US$15.00
 

Firmware updates are done here in a controlled environment to avoid "bricking". If you prefer to replace your GPS-NX01 you can order a new GPS-NX03 and receive a $25 refund by returning your GPS-NX01 as described above. I suggest shipping by mail using a bubble envelope. Please include a printed copy of your GPS-NX03 order.

 

GPS-NX01 Receiver

This section describes the GPS-NX01 receiver. This model was discontinued in January 2013 and replaced with the GPS-NX02 receiver. A copy of the GPS-NX01 User's Manual is available in PDF format.

FEATURES
· Fast time-to-first-fix and ultra low power consumption
· High performance NemeriX chipset tracks up to 16 satellites in parallel
· Supports standard NMEA-0183, Meade LX200, Celestron NexStar and Synta Binary
· Automatically detects telescope type (Meade, Celestron, Synta or none)
· Switches to standard NMEA output after 30 seconds if no telescope is detected
· Lithium cell sustains internal clock and memory (recharges during normal operation)
· LED power indicator blinks to indicate receiver status (see General Information)
· Automatic cold start with no user initialization required
· Compact design with integrated antenna/receiver
· One-year warranty (parts & labor)

SPECS
· Size: 47 x 39 x 16 mm (1.9" x 1.5" x 0.6")
· Weight: 70 g (2.5 oz)
· Tracks up to 16 satellites (-152 dBm sensitivity)
· Warm start in 38 seconds (50%), cold start in 45 seconds (50%)
· Update rate: 1 second (default), adjustable*
· Position accuracy: 3 meters CEP (50%), 7m (90%)
· Velocity: 0.1 meters/second, without SA
· Time: +/- 100 nanosecond synchronized to GPS time
· Altitude: 18,000 meters (60,000 feet) max
· Velocity: 515 meters / second (1000 knots) max
· Acceleration: 4 G, max
· Interface: RS-232 with 2 m (78") cable (PS/2 Female)
· Baud rate: 9600 (default), 4800, 19200, 38400*
· NMEA-0183 Version 2.2 ASCII output: GPGGA, GPGSA, GPGSV, GPRMC, GPVTG
· Meade LX200 Command Set
· Celestron NexStar Communication Protocol (requires hand control firmware version 2.3, 104.0 or 4.0+)
· Synta Binary Protocol (requires hand control firmware version 3.10+)
· User selectable NMEA sentences also include: GPGLL, GPZDA*
· Power: 3.6 to 5.5 V @ 35 ma
· Backup power: 3V rechargeable lithium cell (350 hours)
· Operating temperature: -40 to +85°C (-40 to +185°F)
· Relative humidity: 5% to 90% non-condensing

COMPATIBLE WITH MOST MAPPING SOFTWARE:
(Software not included, requires GPS-USB)
· Delorme Street Atlas
· Fugawi
· OziExplorer
· any software that supports the NMEA-0183 protocol

Click here for information on changing the GPS-NX01 NMEA output settings.

 

GPS-NX02 Receiver

This section describes the GPS-NX02 receiver. This model was discontinued in January 2023 and replaced with the GPS-NX03 receiver.

FEATURES
· Fast time-to-first-fix and low power consumption
· High performance 65-channel SkyTraq chipset
· Supports standard NMEA-0183, Meade LX200, Celestron NexStar, Synta Binary and Vixen HTTP protocols
· Automatically detects telescope type (Meade, Celestron, Synta, Vixen or none)
· Switches to standard 4800 baud NMEA output after 45 seconds if no telescope is detected
· Lithium cell sustains internal clock and memory (recharges during normal operation)
· LED power indicator blinks to indicate receiver status (see General Information)
· Automatic cold start with no user initialization required
· Compact design with integrated antenna/receiver
· One-year warranty (parts & labor)

SPECS
· Size: 39 x 45 x 16 mm (1.5" x 1.8" x 0.6")
· Weight: 60 g (2.1 oz)
· 65-channel (-159 dBm sensitivity)
· Warm start in 35 seconds, cold start in 42 seconds
· Update rate: 1 second (default), adjustable*
· Position accuracy: 2.5 meters CEP
· Velocity: 0.1 meters/second
· Time: +/- 100 nanosecond synchronized to GPS time
· Altitude: 18,000 meters (60,000 feet) max
· Velocity: 515 meters/second (1000 knots) max
· Acceleration: 4 G, max
· Interface: RS-232 with 1.5 m (60") cable (PS/2 Female)
· Baud rate: 9600 (default), 4800, 19200, 38400*
· NMEA-0183 Version 3.01 ASCII output: GPGGA, GPGSA, GPGSV, GPRMC, GPVTG
· Meade LX200 Command Set
· Celestron NexStar Communication Protocol (requires hand control firmware version 2.3, 104.0 or 4.0+)
· Synta Binary Protocol (requires hand control firmware version 3.10+)
· Vixen HTTP Protocol (requires firmware version 1.2 build 31 or newer)
· User selectable NMEA sentences also include: GPGLL, GPZDA*
· Power: 3.6 to 5.5 V @ 45 mA tracking, 80 mA acquisition
· Backup power: 3V rechargeable lithium cell (350 hours)
· Operating temperature: -40 to +85°C (-40 to +185°F)
· Relative humidity: 5% to 95% non-condensing

COMPATIBLE WITH MOST MAPPING SOFTWARE:
(Software not included, requires GPS-USB)
· Delorme Street Atlas
· Fugawi
· OziExplorer
· any software that supports the NMEA-0183 protocol

See below for information on changing the GPS-NX02 NMEA output settings.


CHANGING GPS-NX01 and GPS-NX02 OUTPUT SETTINGS
* A GPS-USB cable is required to adjust the output settings.

GPSView allows you to change the GPS-NX01 and GPS-NX02 output settings for use with other software. In most cases this is not necessary since the GPS will automatically switch to NMEA output after 30 seconds (GPS-NX01) or 45 seconds (GPS-NX02) if a telescope is not detected (see table below).

  1. Plug the GPS-USB cable into your PC. Windows Update will use your internet connection to locate and install the appropriate driver. If necessary you can also download and install the PL2303 driver from
    https://www.prolific.com.tw/UserFiles/files/PL23XX_Prolific_DriverInstaller_v408.zip
    This allows the USB port to operate as a virtual COM port.
  2. Connect the GPS to the GPS-USB cable.
  3. Verify that the GPS LED is turned on (it should be getting power from the PC).
  4. Download and run the GPSView program from http://www.stargps.ca/pub/GPSView.exe.
  5. Select the GPS type, Serial port and 4800 baud.
  6. Click on the "Open Port" button.
  7. Wait until you see NMEA messages (occurs within 30 or 45 seconds of power on).
  8. Choose the output settings that you want and then click "Set NMEA".
  9. You will see NMEA messages being output.
  10. The GPS is now configured. Note that a GPS-NX01 will only maintain these settings as long as the internal battery is charged. Otherwise the output settings will revert to the default rates listed below.
  11. IMPORTANT - the baud rate must be set to 9600 to operate in telescope mode (default).

Message default no telescope
GGA 0 1
GLL 0 0
GSA 0 3
GSV 0 3
RMC 0 1
VTG 0 1

NOTE: The GPS will operate in telescope mode if all NMEA sentences are turned off (0). In this mode the GPS will attempt to determine the telescope communication protocol (Meade, Celestron, Synta or Vixen). If no telescope is found after 30 seconds (GPS-NX01) or 45 seconds (GPS-NX02) the GPS LED will blink rapidly for 5 seconds and NMEA output will begin at 4800 baud as shown in the above table.

 

Using StarGPS-LX

StarGPS-LX was discontinued and replaced by StarGPS-NX in January 2007. You can download the "StarGPS-LX Quick Start Instructions" which are in PDF format.

Setup and Use

StarGPS-LX is designed for use with Meade and other GOTO controlled telescopes that understand Meade LX200 commands. The included GPS-6010-LX receiver sends LX200 commands to your telescope to set the time zone, date, time, latitude and longitude of the current site. Setup is simplified because the telescope already understands these commands and requires no additional software.

If you have an LX200GPS, begin by turning the telescope on and disabling the internal GPS (select Setup> Telescope> GPS Alignment> NO).

StarGPS-LX setup and use is as follows:

  1. Make sure the telescope is turned off.
  2. Connect the GPS-6010-LX receiver to the supplied cable (you can leave these connected).
  3. Plug the end of the cable (labeled ASTAR, LX200, Gemini) into the RS232 port on the telescope controller (Autostar, LX200 control panel or Gemini). If you are using an Autostar you may want to read "Using the GPS receiver, step #2" (in the StarGPS section of this manual).
  4. If using an LX200 Classic/GPS, go to step #6.
  5. Plug the other end of the cable into the AUX port on your Meade telescope or the power output on your Gemini controller. This supplies power to the GPS receiver.
  6. Turn on the telescope. If using an LX200 Classic, go to step #8. You have 30 seconds to complete step #7.
  7. Use the telescope controller keypad (e.g. Autostar) to skip past any messages or date/time prompts until you reach the normal Alignment prompt (e.g. "Align:").Make sure to select NO for Daylight Savings.
  8. Wait until the GPS LED flashes once every 2 seconds. The GPS LED will indicate:

    power-on , location determined and setup complete .

  9. Unplug the supplied cable from the power output and RS232 port.
  10. Proceed with setup/alignment as usual.

NOTE: The local time zone is automatically set to UTC (Coordinated Universal Time) as described in "Setting the Time Zone". Make sure to select NO for Daylight Savings.

TIP: Once the GPS setup is complete you can use the Autostar "MODE" key to view the current UTC date, UTC time, latitude and longitude. Other telescope controllers may offer a similar feature.

TIP: To automatically skip past the Autostar "SUN WARNING" and "Getting Started" messages you can use the "MODE" key to position to the "Select Item:" menu and choose the following: Utilities > Display Options > Sun Warning > OFF [enter] Utilities > Display Options > Getting Started > OFF [enter]

TIP: If you are using a 497/497EP Autostar (Meade ETX/LXD/LX90) you can use your Windows PC with a USB-ASTAR cable (or Meade #505) and the free trial version of StarPatch to update the Autostar so it automatically skips past the date, time and daylight savings prompts.

 

Troubleshooting StarGPS-LX

GPS LED does not light up. Turn the telescope off. Check the GPS cable connections and try again. This problem indicates a faulty GPS receiver or connecting cable (assuming that the telescope power supply is working).

GPS LED lights up but does not blink after several minutes. This indicates that the GPS is unable to get a satellite fix. This can happen indoors and can also occur outdoors if you do not have a fairly open view of the sky (e.g. too many obstructions).

GPS LED blinks but does not flash once every 2 seconds. Turn the telescope off. Check the GPS cable connections and try again. This problem indicates a faulty connecting cable. The GPS is not receiving a response from the telescope/controller.

GPS LED flashes once every 2 seconds but the telescope settings are wrong. Turn the telescope off and try again. If you do not complete step #6 within 30 seconds, the GPS will finish setting the telescope before you skip past the date, time and daylight savings prompts. In this case the GPS results get overridden by the default date and time.

Autostar display goes blank when the GPS starts blinking. Press the "0" key to turn the display back on (any key will do but "0" is the safest). This problem only occurs if the GPS time (UTC) exceeds 8:10 PM. This happens because the Autostar defaults to 8:00 PM and automatically turns the display OFF if the keypad is not used for 10 minutes. When the GPS sets the time to anything between 8:10 PM and midnight (UTC), the Autostar mistakenly thinks the keypad has not been used since 8:00 PM so it turns the display OFF - a minor annoyance.

Autostar latitude is not being set. This problem is due to a bug in Meade software versions 27 and 30. The software version is displayed by the Autostar just after you turn on the power. To correct this problem you will need to update the Autostar software by using the free trial version of StarPatch or the Meade ASU.

Autostar alignment fails (motor stops or extended slewing). This problem is due to a bug in Meade software versions 35, 40, 41 and 42. The software version is displayed by the Autostar just after you turn on the power. To correct this problem you will need to update the Autostar software by using the free trial version of StarPatch or the Meade ASU.

 

GPS-6010/LX Receiver

This section describes the GPS-6010 and GPS-6010-LX receivers. These models were discontinued in January 2007 and replaced with the GPS-NX01 receiver. A copy of the GPS-6010 User's Manual is available in PDF format.

FEATURES
· Fast time-to-first-fix and low power consumption
· High performance SiRFstar IIe/LP chipset tracks up to 12 satellites in parallel
· Lithium cell sustains internal clock and memory (recharges during normal operation)
· Red LED power indicator blinks once a valid GPS fix is obtained
· Automatic cold start with no user initialization required
· Compact design with integrated antenna/receiver
· Standard NMEA-0183 protocol (GPS-6010) or LX200 protocol (GPS-6010-LX)
· One-year warranty (parts & labor)

SPECS
· Size: 59 x 50 x 20 mm (2.3" x 2.0" x 0.8")
· Weight: 95 g (3.3 oz)
· Tracks up to 12 satellites (-142 dBm sensitivity)
· Warm start in 38 seconds, cold start in 45 seconds
· Update rate: 1 second (default), adjustable*
· Position accuracy: 25 meters (95%) without SA, 5 meters (95%) with WAAS
· Velocity: 0.1 meters/second, without SA
· Time: 1 microsecond synchronized GPS time
· Altitude: 18,000 meters (60,000 feet) max
· Velocity: 515 meters / second (1000 knots) max
· Acceleration: 4 G, max
· Interface: RS-232 with 2 m (78") cable (PS/2 Female)
· Baud rate: 9600 (default), 4800, 19200, 38400*
· NMEA-0183 Version 2.2 ASCII output (GPS-6010 default): GPGGA, GPGSA, GPGSV, GPRMC, GPVTG
· LX200 ASCII output (GPS-6010-LX default, with user selectable NMEA output*)
· User selectable NMEA sentences also include: GPGLL*
· Power: 4.75 to 5.5 V @ 80 ma
· Backup power: 3V rechargeable lithium cell (1000 hours)
· Operating temperature: -40 to +85°C (-40 to +185°F)

COMPATIBLE WITH MOST MAPPING SOFTWARE:
(Software not included, requires GPS-USB)
· Delorme Street Atlas
· Fugawi
· OziExplorer
· any software that supports the NMEA-0183 protocol

CHANGING GPS-6010/LX OUTPUT SETTINGS:
* A GPS-USB cable is required to adjust the output settings.

IMPORTANT: SiRFdemo allows you to change many of the GPS-6010/LX configuration settings but we recommend that you only touch the output settings as described below. Changing other settings may result in poor performance or may cause the GPS to stop communicating properly.

  1. If you are using a GPS-USB cable, begin by downloading and installing the Windows USB driver from http://www.stargps.ca/pub/pl-2303.zip. This allows the USB port to operate as a virtual COM port.
  2. Make sure the GPS-6010/LX is attached to your PC (using a GPS-DB9 or GPS-USB cable).
  3. Verify that the GPS LED is turned on (it should be getting power from the PC).
  4. Download and run the SiRFDemo program from http://www.stargps.ca/pub/SiRFDemo.exe.
  5. From the Data Source dialog select the Serial Port COM port and 9600 baud, click OK.
  6. Click on the "connect" icon in the toolbar (5th icon from the left).
  7. If you have a GPS-6010 you will see NMEA output in the "Debug View" and can proceed to step 12.
  8. If you have a GPS-6010-LX then by default there will be no output since LX200 commands are not display. However, if you unplug the GPS-6010-LX PS/2 connector and plug it back in, you will see startup messages in the "Debug View". These messages include the GPS-6010-LX version and copyright information.
  9. Select the "Action" menu and click on "Transmit Serial Message".
  10. Click in the area below "Specify in Hex" and type "11111" (five ones without the quotes).
  11. Select the NMEA Protocol Wrapper (near the bottom left) and then click Send.
  12. Select the "Action" menu and click on "Synchronize Protocol and Baud Rate". This will attempt to switch the GPS-6010/LX to the SiRF Binary Protocol with a baud rate of 38400.
  13. Watch the SiRFDemo window title and wait until it stops cycling thru different baud rate settings. You may see some output in the Debug View or Error View windows (which can be ignored).
  14. Select the "Action" menu and click on "Switch to NMEA Protocol". If this menu item is disabled then you will need to repeat steps 12 and 13.
  15. Choose the output settings that you want and then click Send.
  16. You will see NMEA messages being output to the Debug View window (excluding LX200 commands).
  17. The GPS-6010/LX is now configured and will maintain these settings as long as the internal battery is charged. Once the battery is discharged the output settings will revert to the default update rates listed below.

Message GPS-6010 GPS-6010-LX
GGA 1 0
GLL 0 0
GSA 1 0
GSV 5 0
RMC 1 0
VTG 1 0
MSS 0 0
User 8 0 5

NOTE: User 8 messages represent the LX200 commands (only available with the GPS-6010-LX). When using the GPS-6010-LX with a telescope you should only select User 8 output with an update rate of once every 5 seconds (using a faster rate or including other messages can confuse some telescopes).

 

 

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