Rotation Woes


The logs from my recent sequences:

I’m still quite new at using SGP… I have had it for a while , but I get many fewer opportunities to use it than I’d like. I’m on vacation this week, out in the middle of Nowhere, Kansas, so when the wind isn’t blowing 40 mph, and the skies are clear, I’m trying some astrophotography… I set up a couple of targets, and SGP did the plate solve and centering part perfectly well, but then it refused to rotate the camera to match the reference image. My Moonlite focuser and rotator work off the same controller, and it appears to me to be working; the focuser certainly is. SGP did teh palte solve for teh reference image, and then a plate solve for the view through the 'scope, and then I guess did a nudge of the scope because my alignment wasn’t perfect, but then aborted because it couldn’t get the image to rotate to match the reference. The only way I could figure out to get the sequence to continue was to uncheck the box that tells SGP to validate the rotation.

Can you tell what I’m doing wrong?

I had the problem several times, with at least two targets. I see an error in sg_logfile_20151119213610.txt, but I don’t know what it means or how to get around it. The error in the log shows as, seemingly, a mis-match between asking for steps, or degrees of rotation, though that was not the error presented on the screen, which was just a failure of step 3 in the initial plate solve status screen,

[11/19/2015 9:44:09 PM] [DEBUG] [Telescope Thread] Performing auto center step 3 (rotator)…
[11/19/2015 9:44:09 PM] [DEBUG] [Telescope Thread] Moving rotator to 33.0…
[11/19/2015 9:44:09 PM] [DEBUG] [Telescope Thread] ASCOM Rotator: Moving rotator to 33
[11/19/2015 9:44:09 PM] [DEBUG] [Telescope Thread] ASCOM Rotator: Error in Move(abs) : MoveAbsolute set - ‘-77198.22’ is an invalid value. The valid range is: 0 to 360. (System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation. —> System.Runtime.InteropServices.COMException: MoveAbsolute set - ‘-77198.22’ is an invalid value. The valid range is: 0 to 360.
— End of inner exception stack trace —

It may be still enough and clear enough tonight that I can try again. So I’ll try to get a better understanding, myself, of what’s actually happening.




The MoonLite rotator has it’s own logger which should log exactly what is happening from it’s perspective. It would be useful to see exactly what that thinks is going on. Ideally logs from SGP and the MoonLite for the same time would be good.


PS. send the whole log files,not some fragment. There’s a lot of information that’s not covered by what you think is relevant.


To be clear: I included a snippet of log in my post, but I also provided a link to the whole lot.

I can find no evidence of logs from the Moonlight focuser driver. (They may be here, but I can’t find 'em.) (Why can’t windows programs log everything in one place like a *nix system. What, exactly, is wrong with /var/logs ?)




The ASCOM rotator does not have its own notion of “Sync” like a telescope / mount… so we implement our own. There seems like there could be a bug here in the code that syncs the rotator’s reported PA with the camera angle (east of north). I can’t find anything wrong with the code right now (and it seems to work for most folks). To figure out what is going on, I have better logging for the next beta.


'ullo, Ken.

I’m not at all sure it’s a bug. I’m experimenting right now… as I’m waiting for darkness to fall. I reset the focus controller… (this is the dual focuser/rotator controller), and as soon as I opened the Moonlight Controller App… it complained that it was beyond its mechanical limits, and proceeded to rotate the camera about 150 degrees. It offered no explanation for this behavior, beyond the initial notice. I’m now happy with where the camera is sitting. (I’m calling it “zero”.) The rotator thinks it is at zero degrees… although it is at some high number of steps, now. I’ll eat a little dinner and then see how it behaves once the stars come out.

(Wish me luck!)




OK… but, I will say that the logs look pretty suspicious. SGPro asks the rotator to move to 33 degrees. Then, after going through the “offset” filter (the difference between reported PA and camera angle (east of north), it seems like we suddenly ask your rotator to move to -77198.22 degrees. This does not necessarily mean there is a bug in SGPro, but at the very least SGPro might not be protecting itself (and you) from bad data.


I’m not trying to be rude… I haven’t responded because I have nothing more for you for the moment. The last time I set up, the clouds moved in as soon as I got everything connected, and now I’m back at work… I’ll see if I can test things out again, if the clouds clear up, this weekend.

I note that you’ve made a change in v .19… I’ll load that one up before I try again.