NexStar Resource Site

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Firmware Versions on the NexStar GT, Orion StarSeeker and Tasco StarGuide

NexStar GT, StarSeeker and Tasco StarGuide scopes have two sets of processors.  There are processors in the hand control (HC) and there are processors in the base of the scope in a section known as the motor control (MC).  The motor control is not upgradeable and in any case, Celestron only created a single version.  Hand controls prior to version 4 can NOT be updated, but if you have a version 4 hand control (owners of older versions read this for info on purchasing the upgradeable hand control), the firmware can be updated (read this).

For additional details about features on newer versions, check the Manuals section of this web site.

As of mid-2012, the NexStar GT models sold through special resellers (Costco NexStar GTs, the Orion StarSeeker models and NexStar GTs sold in Japan) have the NexStar 4/5 SE motor control board and are sold with the NexStar+ hand control.  Please refer to the NexStar 4/5 SE firmware page for versions applicable to these models.

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HC Versions
(firmware files are named GT)

  • 4.04 - created for the NexStar 102GT sold only at Costco (model #22903).  IMPORTANT - this version only supports the mounts with the larger drive gears - the NexStar 4, 102, 114 and 130 GT.  Removed the model selection at start up and in the menu (this is the reason it only supports the mounts with larger drive gears) - it is advisable that you check the Slew Limits after loading this firmware to ensure the optical tube does not make contact with the mount or tripod.  Added the Abell list and Index Catalog (IC objects) - there no reason to upgrade to this version unless you need either of these catalogs.
  • 104.0 and 4.03 - Just prior to discontinuing the general sale of the GT series (they have been replaced by the SLT series though there are some GT models still being sold overseas or at some US retailers), Celestron upgraded the hand control to include the features found in their latest scopes.  Version 104.0 shipped with all of the StarSeeker scopes and the last of the GT series beginning in October 2005.  Version 104.0 is not a user-upgradeable hand control.  Version 4.03 is available for GT scopes by purchasing the user-upgradeable hand control separately.  This version greatly improves tracking accuracy, keeping objects in the field of view for as long as you care to view them.  The tracking is still suited mainly for visual and perhaps web cam imaging as the necessary corrections made by the hand control are significant and don't lend the scope to imaging.  Also, this version supports the more advanced serial port control commands.  This allows programs like NexRemote and NexStar Control Pad to work with the GT/StarSeeker scopes.  New features include SkyAlign, Solar System Align, Auto Two Star Align, One Star Align, Identify and Constellation Tour. Read this for more information on the new hand control.
  • 101.0 - An updated hand control with all features described in this review.  If you have the original GT hand control or version 100.7, contact Celestron for a replacement or purchase the user-upgradeable hand control -  read this for more information.
  • 100.7 - This hand control was mistakenly shipped with several scopes in early 2004.  Basically it is the same as version 101.0, but, it does have a problem in the Two Star Align routine.  If you start the Two Star Align, you will find that you are only offered alignment stars starting with the letters A through F.  Also, this version does not support the use of 24-hour time during alignment - you must use AM/PM.  Contact Celestron about upgrade options if you have version 100.7 OR purchase the user-upgradeable hand control - read this for more information.
  • Original GT - We don't actually know the version number of the original hand control, but it is easily distinguished due to the fact that it only offers the Auto Align routine - no Two Star Align and no Quick Align.  This is the hand control shipped with the GT scopes made before December 2001.  The Tasco StarGuide hand control is basically this same version.  See the Odds and Ends section for a list of problems with this version.  Contact Celestron about upgrade options if you have the original GT hand control OR purchase the user-upgradeable hand control - read this for more information.

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MC Versions

  • 1.0 - We don't actually know the version number of the MC firmware on the GT and StarGuide scopes, but there has only been one version, so for now I'm calling it version 1.0.

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Determining Versions

As noted above, we do not know the version number for the MC firmware.  For the HC, first check for the Version option on the Utility menu - this will report HC version numbers on version 104.0 and 4.03.  If you do not find a Version option, check to see if you have the Two Star Align option after powering up the scope.  If you do not, you have the original GT hand control.  If you do have the Two Star Align option, after starting the alignment you will see that the hand control displays the name of the first available alignment star - Achernar.  Press the Up button (6 on the number pad).  If the display shows Fomalhaut, you have version 100.7.  If the display shows Vega, you have version - 101.0.

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Michael Swanson
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