NexStar Resource Site

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Firmware Versions on the NexStar GPS Series

NexStar GPS 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 MC firmware can be updated by the owner (read this).  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.

Please email me if you have a scope with different versions than listed here.

HC Versions

  • 4.13 - This version allows the motor control (MC) firmware to be upgraded via the port on the bottom of the hand control.
  • 4.12 - The most significant change in this version is variable brightness control for the display and buttons - values are from 0 (off) to 8 (full brightness).  There is also a fix that reduces (but does not eliminate) the chance that the display comes up blank the first time you power up, a problem much more prevalent in cold weather.  The fix on those occasions when it does still come up blank remains the same - turn off the power, wait a couple of seconds and turn on the power again.  The Version menu item has been changed - it now displays the mount model after displaying the HC and MC versions.  This version is also the first to support the new NexStar SE mounts. 
  • 4.10 - The most significant change in this version is Sync.  Sync is available both via the hand control and via PC software (TheSky, Starry Night, etc.).  This provides very accurate GoTo pointing in the area of the sky where the Sync is performed and it allows the PC software to match with the actual position the scope is pointed to.  Other new features: Calibrate Goto (help to improve GoTo accuracy), general pointing accuracy improvement, a display of the polar alignment error (when EQ mounted on a wedge) and the ability to start PEC playback and proceed with normal use of the hand control.
  • 4.03 - Minor change from 4.02.  GPS scopes manufactured from October 2005 forward where supplied with the user-upgradeable hand control and this firmware version.  Owners of older GPS scopes can take advantage of this new firmware by using NexRemote or by purchasing the user-upgradeable hand control separately (owners of older versions read this).  Click here for more details on the features in version 4 of the hand control.
  • 4.02 - First available for use on NexStar GPS series through use of NexRemote.  This version provides several new features.  First, the physical 4.02 hand control is the first version that can be upgraded to new firmware by the user.  It also introduced the new alignment methods - SkyAlign, Solar System Align and One Star Align.  Also added are Precise GoTo, Identify, Constellation Tour and few other new features.  Click here for more details on version 4 of the hand control.
  • 2.2 - A minor upgrade that includes support for the NexStar 5i/8i and a slightly more accurate Wedge Align routine.
  • 1.6 - The updated hand control with all features described in this review.
  • 1.2 - Shipped with original NexStar 8 GPS and 11 GPS scopes. Several features have since been added and if you have this version, you should definitely upgrade.  To upgrade, purchase the user-upgradeable hand control (read this for more information) or contact Andre Paquette (click here for more information) regarding upgrading a version 1.2 hand control to version 1.6 or 2.2.

MC Versions

  • SA 4.00 - Prior to being discontinued, the NexStar GPS was sold in a SkyAlign version - the GPS-SA.  The MC version on this scope was SA 4.00.  This version is the same as 4.06 with two exceptions.  First, it will not function with hand control firmware below 4.02.  Second, it is not possible to load older versions of MC firmware (all those listed below) over this version.
  • 4.06 (hand control 2.2 or earlier will display this as 4.6) - In addition to the fixes introduced in 40.40, this newer version also improves autoguider performance, fixes a runaway that occurred when at rate 1 or 2 and using the "double key press" for rate 9, fixes PEC issues and is the first version to support Celestron's free PECTool utility.
  • 40.40 - This is a beta (test) version but was released to the public.  Fixed autoguider problems including runaway slew when autoguiding.  Finally fixed the hop in Alt-Az mode.
  • 4.5 - Fixed a minor problem with manual slewing at rates 5 and 6.
  • 4.4 - That pesky hop was still present on some scopes and this version attempted to address that problem, though it turns out that a some scopes still have the problem when running this version.
  • 4.3 - Incorporates a slightly improved tracking algorithm that attempted to eliminate a slight hop seen in some scopes when used in Alt-Az mode.
  • 4.1 - This version features silent, accurate tracking and support for all the latest NexStar features. It also improves the encoder resolution to 0.112 arcsecond. Unfortunately, it introduced a slight hop seen in many scopes when used in Alt-Az mode.
  • 3.0 - This version is characterized by the 'bee in a can' tracking sound that solved the vibration issue. It does not support some of the newest features such as cordwrap prevention and advanced control via a Personal Computer.  This is also the first version that allowed user upgrades to the MC firmware.
  • 2.0 - Shipped for a short while in both the NexStar 8 GPS and 11 GPS. This version overcame problems with tracking, but there were still some problems with vibration in some telescopes.  If you have this version, read this.
  • 1.0 - Shipped only in the original NexStar 11 GPS. This version had some problems with smooth tracking and should definitely be upgraded. The most detrimental problem is a vibration that affects high magnification views and astrophotography.  If you have this version, read this.

Determining Versions

With hand control version 1.6 or higher, you will find a Version option on the Utility menu. If you don't find a Version option on the Utility menu, you have hand control version 1.2 and motor control version 1.0 or 2.0. 


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