Tracking stopped after mount flip [cable snag]

[Larry Owings]

The past two nights I have been on an asteroid for the whole night and after the mount flipped tracking was off. Every image I acquired after the flip had long streaks of stars, including the pointing image taken immediately aafter the flip. I was running plans that are essentially identical to the plan I have been running sucessfully for the past week except for the asteroid position. Every image taken after the mount flip has streaked stars in it. I have looked carefully at the ACP Log in the area of the mount flip and see no difference between the nights when the failure occurred and successfull nights.

Any ideas would be greatly appreciated because I am not able to get any usable images after a mount flip.

Larry Owings

[Steve Reilly]

Are you guiding on both sides? Is it possible that when the flip occurs the
guide star isn't found?

Steve
www.astral-imaging.com

-----Original Message-----
From: Larry Owings [mailto:]
Sent: Wednesday, September 21, 2011 3:22 PM
To: sreilly@hughes.net
Subject: [ACP Observatory Control Software] Tracking stopped after mount
flip

The past two nights I have been on an asteroid for the whole night and after
the mount flipped tracking was off. Every image I acquired after the flip
had long streaks of stars, including the pointing image taken immediately
aafter the flip. I was running plans that are essentially identical to the
plan I have been running sucessfully for the past week except for the
asteroid position. Every image taken after the mount flip has streaked stars
in it. I have looked carefully at the ACP Log in the area of the mount flip
and see no difference between the nights when the failure occurred and
successfull nights.

Any ideas would be greatly appreciated because I am not able to get any
usable images after a mount flip.

Larry Owings

This message was posted via email

[Bob Denny]

Has this "just started to happen"? Or is this the first time you've tried to let ACP work through the meridian (I think you have before by your post)? Is there a way you can set your alarm and see what might be happening first hand? ACP will not turn off tracking during a flip. It will turn it off BEFORE a flip, while it's waiting, though. Can you think of anything else that might have changed?

And Steve has another good theory, maybe the best one. It might not be guiding. If you can stay up and watch that would tell. If not there are a few reasons. I can go through the checklist with you. Basically, there are a bunch of guiding configuratiions from external guide scope to off-axis/rotator. While you can get guiding after calibrating looking east if ACP doesn't know what the guider is, it can't manage the changes needed after a flip. I'll be out for a bit but just call and leave voicemail. I'll return the call ASAP.

[Larry Owings]

I have not changed anything I know of in the setup of ACP, or other software installation/removal.

Immediately after the flip a pointing exposure is made. It will not plate solve because the mount is apparently not tracking - stars are streaks. It hasn't tried to start the autoguider. The plan has the external autoguider running and it was indeed running properly prior to the mount flip.

Tonight I will run a plan that takes a couple of images in the east, with autoguiding, then goes to another target in the west and watch it to see what happens. I will report back with results.

Larry Owings

[Larry Owings]

One more note, I have been using ACP for years, with an external scope autoguiding, going through a meridian flip -- up until the two previous nights.

Larry Owings

[Bob Denny]

OK, then something has changed. The problem is to identify just what it is. I don't have any theories at the moment... anyone else? I'm often surprised by the insight that some of the guys here have!! FYI Steve Reilly... I didn't think of guiding problems but he was right on with that theory (even though it turned out to be incorrect, but what the hell, we're looking for ideas!!)

[Larry Owings]

Last night I ran a plan that started just before the meridian and continued imaging, and autoguiding, through the meridian flip. All worked well.

I had turned on the AP V2 driver logging and left it on for the rest of the night while I ran the plan for the asteroid I am working. I had the same problem with streaked stars after the meridian flip. Looking at the AP V2 log I found an entry

"187992 2011-09-21 23:25:21.453: Telescope: Error : MOTOR STALL DETECTEDS: 1"

This occured during the flip time which was from 06:24:48 to 06:25:41 (23:24:48 to 23:25:41 local).

Therefore I have a cable snag problem that I didn't see when I ran the earlier plan, and I think the reason I didn't see it was because the failed plan target was 10 Deg. lower in Alt.

Tonight I will re-run the test plan at the exact same Alt and Az and watch the cables.

Larry Owings

[Bob Denny]

OK, that makes sense, and congratulations on the detective work! Engineers rule!! (pun intended, see below)

[Larry Owings]

Boy do I have egg on my face! I had made an adjustment device for my autoguider scope mount that had two bolts sticking out enough to hit the mount. That is what stopped the mount from flipping, but only if it started the flip from a high declination like the particualr asteroid I was working.

Thanks for the helpful hints. All is ok now.

Larry Owings

[Bob Denny]

Hooray!! Don't worry about eggs... I posted Hot Fix 2 yesterday with a couple of omissions... the eggs were flying here!!