The NexStar User's Guide II - Excerpt from
NexStar Control Protocol
Communication protocols have various technical parameters to allow two
devices to communicate over some medium. Both devices must utilize all the same
parameters or communication will not be possible. The NexStar+, NexStar version
4 and StarSense hand controls share the same protocol which traces its roots
back to the Celestron Ultima telescopes of the 1990s. It is useful to understand
how this protocol evolved since the introduction of the first NexStar telescope
- The first NexStars on the market were the original NexStar 5/8 sold from 1999 to
mid-2002. These scopes had a silver optical tube and no connector ports on the
top of the mount. They also have a control protocol unique to them, so if a
software package does not state specifically that it is compatible with this
mount, it most likely will not communicate.
- Next on the market were the NexStar GTs in 2000. The original hand control can
be identified by a lack of the alignment option named Two Star Align. The
original hand control had a slight change to the control protocol from the
NexStar 5/8 and thus introduced the second unique protocol. There are very few
software packages compatible with this hand control.
- With the advent of the NexStar GPS series in 2001, Celestron introduced what
would become their final (up to this time) control protocol. All Celestron
computerized mounts introduced since then use this control protocol.