Welcomed home my EQ8-R last week and along with its RC12 payload have begun the process of integrating it into my workflow, the shambles that it is.
I'm a Stellarmate user/customer (I believe in open source but also believe people need to eat!) and hit a few snags, so thought I would share my experiences here hoping that my mistakes don't become someone elses.
The first thing about the mount that I noticed (other than just how wonderful it looks!) is how quiet it is even compared to my "old" EQ6-R, the high pitched whine is gone, it's a steady low pitched set of motors that inspire confidence.
Using EQMod and direct connect to the USB port in the mount it looks and acts exactly like the EQ6 as you would expect, however the Autohome button called out to me - for those not familiar with it, this is a "Paramount" style feature designed for remote observatories to enable you to get the scope back to a known "good" position should it lose its way between slews and restarts, etc but in order to work, more hardware is needed in the mount, either additional encoders (Aux encoders) which used to be called Freedom Find or some sort of home position sensor.
To my understanding the EQ8-R no longer has Freedom Find encoders like the EQ8 but instead has a different solution - whatever the actual detail, the problem is that when you attempt to use Autohome in the control panel it fails with an error saying act it can't detect the Aux encoders and fails to Autohome. Not a great start for the new mount given that I am running semi-remote! Logged a bug/feature request at Jasem's request and have also asked SkyWatcher for assistance - let's see what gives.
Undaunted I decided to give this wonderful beast time to do some imaging, thinking it was a long focal length (2300+mm) I naturally assumed that guided using my OAG would be the best way to go.
I'm not a PHD2 user - have never really understood the need for it with the built-in guider having done a great job for me in the past, so I went with what I know and here's where things get more interesting (to be clear what follows is probably NOT an EQMod driver problem).
Tracking/guiding was incredibly smooth on one axis, less than 0.4 arc secs RMS, however in the other it was horrendous, nearly double the RMS at 0.9 and considerable deviations and corrections required. The scope seemed to be having trouble keeping the guide stars in the FOV, not a complete surprise at this FL but certainly far from stable - my guess is a balance issue with teh scope, in that it's too balanced east/west.
So being in a hurry (never a good idea) I thought I'd use the PPEC control panel and do some training of the two axis in the hope the mount would be smarter than me and figure out a way to smooth it out. Whoa was that a mistake!
PPEC training has always been something I've avoided in teh past with the EQ6 because it usually resulted in my INDI connection crashing (I run client on my Mac, Stellarmate on an RPi at the mount) - and the tracking and guiding was always good enough for shorter FL's that it was never really a problem.
This time, clicked on "train" and the good news, no crashes. Both axis trained after a few (4) minutes. What happened next I still don't completely understand....
I switched on PPEC through the Control Panel and a short period of time later my imaging session was returning random dark patches of "sky" and the guider had lost all stars.
I finally ventured out to the dome to find the scope weights up and the indicator light flashing red (meaning PPEC was enabled).
Lesson - don't turn on "new" features without either a camera in the dome or better yet being physically close enough to observatory to catch potential problems!
I wasn't sure what the problem was so the next training session a few nights later I did the same thing, but this time sat next to the scope - maybe it's how I am using the PPEC training feature (in my defence, the documentation seems non-existent or hard to find) but I can report it's the same problem. Training finishes, but as soon as the RA PPEC is enabled the scope goes into what looks like accelerated sidereal tracking on the RA axis.
Switching RA PPEC off I noticed that the DEC axis does something similar with PPEC enabled albeit at a much slower rate.
My assumptions are that I'm either running PPEC training incorrectly OR that there's a subtle difference between EQ8 and EQ8-R firmware or APIs that are related to both problems.
Clearly more investigation to be done, I'm happy to run any diagnostics or traces that people might want to see especially if you are thinking about adding one of these otherwise amazing
mounts to your observatory.