NexStar Resource Site

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Ports and Connectors on LCM Scopes

Click here for a diagram by Larry McNish depicting NexStar cable/port connections.

  • RS-232 or USB Port - located on the bottom of the hand control.  Hand controls manufactured prior to 2014 are RS-232; those manufactured starting in 2014 are USB.  The RS-232 port is presented as an RJ-22 jack (looks like a small telephone jack).  The USB port is a mini-USB as found on devices like digital cameras, not the more common micro-USB found on smartphones.  The primary usage of this port is for controlling your scope with the wide variety of astronomy software available for PCs, Macs and PDAs.  A secondary usage is for updating the firmware in the hand control or mount's motor control - details are found here.  Details about the required connector cables are found in this section of the website.
  • HAND CONTROL Port - located on the top of the mount base.  The primary usage of this port is for connecting the hand control.  The connector is a 6 conductor RJ-12.  The signaling is TTL and so a serial port on a PC should not be connected to this port.
  • POWER CORD Connector - located on side of the mount base.  This is the connector for the power source driving the scope - details on this connector are found here.

Also, it should be noted that Celestron offers an Auxiliary Port Accessory Kit (part number 93965) that can be connected to the HAND CONTROL port and then provides the following ports:

  • AUX 1 and AUX 2 Ports.  Two AUX ports with the same function and description noted for the HAND CONTROL port above.  The hand control is connected to either of these ports and the Auxiliary Port Accessory is connected to the mount's HAND CONTROL port.  Also, the optional CN-16 GPS module (part number 93966) can be connected here.
  • PC Port.  This port can be used with two software packages from Celestron.  The first is for upgrading the motor control firmware, though with hand control version 4.13 or higher, motor control firmware can be updated via the RS-232 port on the bottom of the hand control as well.  The second is for a PC-based virtual hand control called NexRemote - details are found here.  NexRemote can also be used with the LCM by connecting the PC via the RS-232 port discussed above - the PC port just has the advantage of not requiring the real hand control to even be connected.  The connector for this port is an 8 conductor RJ-45.  The signaling is standard RS-232 levels.  When using NexRemote with the PC port, you need a "programming cable", not the standard RS-232 cable used to connect to the port on the bottom of the hand control.  Click here for details on the cable used to connect this port to a PC.

And finally, Ken Hutchinson has put together a document detailing how to build an adapter that connects to the HAND CONTROL port and then provides a PC Port that works as described above.  For more on this adapter, click here.

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