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StarDate GPS Adapter FAQ Table of Contents

  1. What is the StarDate GPS Adapter ?
  2. What Celestron telescopes will  it work with ?
  3. What GPS receivers will it work with ?
  4. Why do I need GPS for my telescope ?
  5. What is the difference between the StarDate GPS Adapter and the CN-16 ?
  6. What alignment methods does the StarDate GPS Adapter support ?
  7. Why does my telescope display the wrong time after alignment?
  8. Why didn't the StarDate GPS Adapter update my time zone/daylight savings time setting?
  9. Does the StarDate GPS Adapter need batteries ?
  10. I have an AS-GT Series telescope - can I use a modular splitter instead of the Celestron AUX Port Accessory?

What is the StarDate GPS Adapter?

The StarDate GPS Adapter is a device that allows you to use most NMEA-compliant GPS receivers with your Celestron telescope.  If you have a handheld GPS receiver, this allows you to add GPS capability to your telescope without having to buy a Celestron CN-16 GPS accessory, or use a PC as a "translator" between your handheld GPS and your telescope.  The StarDate GPS Adapter provides nearly all the functionality of the CN-16 (except for north direction sensing), and makes your GPS receiver look like a CN-16 from the telescope's point of view.

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What Celestron telescopes does it work with?

The short answer is, any Celestron telescope that is equipped with an AUX port.  This includes:

  • NexStar 5i/8i
  • NexStar 8i Special Edition
  • CGE Series
  • AS-GT Series (with Celestron #93965 AUX port accessory kit)
  • SLT Series

Note that while the NexStar GPS Series and CPC Series telescopes do have an AUX port, the StarDate GPS Adapter is not intended to be used with either of these series, since they already have built-in GPS receivers.

Early model NexStar 5/8 (non-"i" telescopes) cannot be supported, because they lack an AUX port as well as firmware GPS support in the hand controller.  The serial port on the bottom of the hand controller is not an AUX port, and cannot be used to enter time/date/location in these models.

Also please note that the Celestron GT series and the Orion StarSeeker telescopes do NOT have an AUX port, and therefore are not supported.  You CANNOT add an AUX port to these telescopes by using the Celestron #93965 AUX port accessory kit.

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What GPS receivers will it work with?

The StarDate GPS Adapter will work with any NMEA 0183 compliant GPS receiver that has a serial (RS-232) port and generates $GPRMC sentences.  You will need to supply a "PC adapter cable" for your GPS receiver, to connect it to the RS-232 connector on the StarDate GPS Adapter.  Please check with your GPS receiver's manufacturer for availability of a PC serial cable for your particular receiver.

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Why do I need GPS for my telescope?

You don't need GPS for your telescope to work, but GPS offers a tremendous improvement in convenience and ease of alignment.  The modern "goto" telescope must be accurately aligned in order to be able to successfully locate objects in the night sky.  In order to achieve accurate alignment, the telescope must know your exact location, time, and date.  Without GPS, your telescope's hand controller will ask you to input your longitude, latitude, local time, date, time zone and daylight savings time status every time you turn the telescope on and begin an alignment.  This process can be time consuming and prone to error, resulting in either poor alignment or an alignment failure altogether.

With a GPS-equipped telescope, the telescope hand controller receives all the required longitude, latitude, time and date information from the GPS receiver, virtually eliminating any chance of error, and saving you potentially dozens of keystrokes during alignment!

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What is the difference between the StarDate GPS Adapter and the CN-16 ?

The CN-16 is a GPS receiver accessory offered by Celestron to add GPS capability to their telescopes that have an AUX port but are not factory-equipped with GPS.  The CN-16 is a proprietary GPS receiver design, and can only be used with your Celestron telescope.

The StarDate GPS Adapter is just that: an adapter that will let you use any handheld GPS receiver (Garmin, Magellan, etc) to add GPS alignment capability to your telescope.  If you already have a handheld GPS receiver, you don't need to buy an expensive proprietary GPS receiver for your telescope.  If you don't yet have a handheld GPS receiver, you may wish to consider buying one and a StarDate GPS Adapter instead of a CN-16, because you can use the GPS receiver for hiking, navigating in the car, boating, geocaching, etc.

The Celestron CN-16 accessory does include a magnetic compass direction sensor that is used in some alignment methods (specifically "GPS Align" on the NexStar series).  The StarDate GPS Adapter does NOT have a direction sensor (neither do most GPS receivers), therefore it does not support the "GPS Align" alignment method (ironically).  This alignment method is being phased out by Celestron in newer telescope and hand controller models to avoid technology licensing issues.

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What alignment methods does the StarDate GPS Adapter support?

The StarDate GPS Adapter supports most Celestron telescope alignment methods except "GPS Align" on the NexStar series, which requires a magnetic compass direction sensor to allow the telescope to automatically find north.

For hand controllers with firmware version 2.2 or later, the hand controller will automatically use the StarDate GPS Adapter to obtain time, date, and location during alignment.  For hand controllers with firmware version 2 or older, you must select "View Time-Site" from the hand controller menu prior to beginning alignment in order for the telescope to obtain data from the GPS.

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Why does my telescope display the wrong time after alignment?

Chances are your telescope time zone setting is incorrect.  Celestron telescopes request time and date from GPS receivers in UTC (Univeral Coordinated Time), so in fact the telescope did receive the correct time and date from the GPS receiver and is properly aligned, but the hand controller will display "local time" according to the time zone that is set in the hand controller.  It is not necessary to change the telescope time zone if you are travelling, as it will still get the correct time and date from your GPS receiver and the StarDate GPS Adapter, however you can change the time zone for convenience if desired.


Why didn't the StarDate GPS Adapter update my time zone/daylight savings time setting?

If you travel with your telescope and use the StarDate GPS Adapter to align your telescope, you may find that your time zone and/or daylight savings time settings are not updated in the telescope hand controller.  Your Celestron telescope requests GPS time and date in UTC (Universal Coordinated Time), and performs its alignment based on UTC time.  In fact, the NMEA protocol used by your GPS receiver doesn't have any means of specifying time zone or daylight savings time, so the telescope can only align based on UTC time.  If you wish to change time zone or daylight savings time settings in the hand controller, you must do it manually.


Does the StarDate GPS Adapter need batteries?

No!  The StarDate GPS Adapter gets its power from the telescope AUX port, therefore there are no batteries to buy or replace.  Because most telescopes are operated under battery power themselves, the StarDate GPS Adapter has been designed to use very little power, and in typical use will have virtually no effect on your telescope's battery life.

Your GPS receiver will likely need its own batteries, however.  Please consult your GPS receiver user's manual for details.


I have an AS-GT Series telescope - can I use a modular splitter plugged into the Hand Control port instead of the Celestron AUX Port Accessory to add an  AUX port?

At this point, NO.  The current version of the StarDate GPS Adapter will not work with a simple 2-way splitter plugged into the hand controller port; the Celestron #93965 AUX port accessory kit has additional internal electronics that are required for the StarDate GPS Adapter to operate with the AS-GT.

In addition, please note that the use of a modular splitter may damage or destroy your hand controller if incorrectly connected!  The short cable that comes with the StarDate GPS Adapter reverses the wires from end to end, so if you plug a splitter into the StarDate GPS Adapter and run the StarDate's cable from the splitter to the hand controller port on the mount, then plug the hand controller into the splitter/StarDate combination, you will reverse the signals applied to the hand controller and likely destroy it!  For this reason, Earthshine Technologies recommends against and does not support the use of a modular splitter with the StarDate GPS Adapter.  You do so at your own risk!

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Copyright 2006 Earthshine Technologies LLC.   All rights reserved.
Revised: January 27, 2006 .