NexStar Resource Site

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Firmware Versions on the Celestron CPC Series

Non-English Hand Control Owners - read this.  The
information below is for English-version hand controls.

Celestron CPC 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).

There have been two versions of hand control available for the CPC:

  • Hand control version 4.X.  This hand control can be updated by the owner.  Read this for step by step instructions on upgrading the firmware.
  • The NexStar+ hand control.  This hand control can be updated by the owner and began shipping with new CPC scopes in January 2012.  It is also available for purchase since February 2012.  Read this for info on this new hand control and this for step by step instructions on upgrading the firmware.

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

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NexStar+ Hand Control

Celestron has posted an official document detailing all firmware versions for the NexStar+ hand control:
Check back periodically for updates.

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Version 4 Hand Control
(firmware files are named NXS)

  • 4.21 - Fixed the RS-232 negative declination bug found in 4.20.
  • 4.20 - This version has a bug - if you connect a computer/PDA/smart phone to the RS-232 port and direct a GoTo to an object with negative declination, the scope will instead point to +90 declination.   It is recommended you upgrade to 4.21 or higher.   Fixed an error in the GoTo RA-Dec menu item.  Hand Control now reports immediately if the are communication ("No Response") difficulties at start up.  No Response errors now give a "Press UNDO to continue" option.  For mounts with a GPS module in use, changed the messages displayed to clarify when the GPS was still attempting a link and when it was successful.
  • 4.18 - An important upgrade with many new features and fixes.  The hand control now calculates positions with respect to precession - in other words, previously all coordinates were J2000 while this version uses JNow.  Polar alignment routine is now under the Align menu and allows alignments on stars other than Polaris.  Additionally, after polar alignment, the scope no longer requires a new alignment.  Fixes problems with Southern Hemisphere alignments.  Pressing ALIGN while in the Named Stars menu now takes you to the Align menu.  Sets slew rate to 5 upon waking from hibernation.  The Factory Settings menu item now resets all motor control settings (as well as the hand control settings) and will force the user to restart the system.  The hand control is now locked when performing a motor control upgrade via the port on the bottom of the hand control.  Added two PC control commands: one to undo any current "Sync", the other to retrieve the local sidereal time from the hand control.  Fixed error when using SAO stars (selected from the STAR button) as alignment objects.  Fixes a bug which changes rate if a direction button is pressed after the RATE button.  Fixes a rare problem updating the motor control through the hand control.  Corrects Abell objects with negative magnitudes.
  • 4.15 - Know to have shipped on some SE scopes at the end of 2009, this version was never officially released by Celestron.  One CPC owner has reported that their scope was shipped with 4.15 as well.  It includes all of the features of 4.18, except the Southern Hemisphere fixes, the SAO star as alignment object fix and the fix for the rare problem updating the motor control through the hand control.
  • 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 - Original version for the NexStar CPC.

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MC Versions

  • 5.14 - Corrects a problem with the cordwrap prevention feature.
  • 5.07 - Original version for the NexStar CPC.

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Determining Versions

Use the Version option on the Utility menu.

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Michael Swanson
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