Scheduler Failure due to telescope limits: TheSky X Telescope Limit

[Peter Brackenridge]

I have a Paramount ME and have some restrictions to stop the telescope hitting the pier. This is set in the Paramount TCS.

Scheduler was imaging and as the object came up towards the meridian, the telescope reached a limit and the SkyX Brought up a dialog box stating this.

This caused Scheduler to stop working and brought up Hardware Error in ACP, and required Operator Intervention to get things working again.

The problem is around the meridian. I can't change anything in STX or the Paramount ME otherwise I won't have protection of the telescope.

I am not sure there is any way to prevent this happening, whether changing the flip setting in ACP Preferences Telescope would help. At the moment I have flip settings East-West and West-East set to 0 minutes. If I changed this to flip 5 minutes before the meridian, I am assuming then that I would run into trouble coming up against telescope limits once flipped, as wouldn't the stope try and go to track the image even if it hadn't yet crossed the meridian?

Peter

[Peter Brackenridge]

Maybe I should extend the "minutes to assure flip" from the current 2minutes, to say 5minutes, would that possibly help?

[Bob Denny]

I'm sorry Peter I am not very clear on what your restriction is. And this "just start happening"? Did you recently make an architectural or imaging train change that made this a requirement? It's possible that ACP Expert won't be able to accommodate that unusual of a restriction in the hardware. Can you explain a bit more? If your restriction is around the meridian, it may be possible to have the scheduler avoid starting Plans whose Observations would extend to within some hour angle of the meridian. Can the scope flip safely if started far enough to one side and with it going far enough to the other side?

[Peter Brackenridge]

Thanks for your reply Bob. I had placed the telescope either side of the pier and taken readings a the two spots where it would hit the mount. That information gets put into the Paramount ME TCS and then the mount won't move the telescope past those positions (my pier is a bit wide!). I had done this a few months ago as I was getting the occasionally collision, which would mean I had to physically to to the observatory to get release it. Now that doesn't happen, but I think when ACP is tracking an object that comes up against this restriction, then the dialog box comes up in TSX saying it can't go beyond this point or something like that, and then ACP produces a hardware type error and Scheduler stops working..

Yes the restriction is around the meridian, such that I cant track past the meridian, and with the restriction, can't track up to the meridian either it would seem.
Regarding the flip- if it was to flip earlier on one side so it didn't come up to the meridian, then what would happen when it flips, won't there be a problem of it tracking past the meridian on the other side? This is where I get a bit confused.

Peter

[Bob Denny]

I understand. This is an unusual (extremely rare) requirement. There are a couple of things that ACP Expert can do but neither are a perfect solution. First would be to set the Tilt-Up Limit in ACP itself. That would prevent it from slewing to a point above a certain altitude, say 80 degrees. However that won't prevent it from sitting there while the scope is tracking into an unsafe area. When using ACP in "live" mode it's up to you to prevent it from doing this, and it can be difficult. For the Scheduler, you can set Hour Angle Limits as a constraint. THe problem here is that it is a severe constraint... it will stay that far away from the meridian not just the zenith. Scheduler won't even start a Plan that would extend into that range of hour angles. An hour is 15 degrees. Calculate how far away from the meridian you would need to stay in degrees, divide by 15, and put that in as an hour angle. Unfortunately this only works on one or the other side of the meridian, so if youj want to observe a target across the meridian, you'd have to put it in twice, once for the east side, once for the west, with the hour angle range -0.5 to 0 to keep it 7.5 deg east, then 0.5 to 6 to force it to wait till the target it a half hour west before starting it.

I would try to find a mechanical solution to this.

[Peter Brackenridge]

Thanks Bob

Yes that sounds complicated ! The position it has a problem isn't even the zenith or high altitude, it is a position where there is a telescope control box on the side of the telescope which comes up against the pier and I cant see how I can change that. I will see how it goes, and how often the problem happens and take it from there.

Thanks again

Peter

[Bob Denny]

OK, well I did my best to let you know what tools you have available, and to visualize what your actual situation is. I hope you can find a way forward.

[Peter Brackenridge]

Yes thanks for trying Bob. I cant see a great solution so far. Just had the same problem come up, with the same larget image. The altitude was only 68 degrees but was approaching the meridian.

I attach the error. Ignore the position of the larget, as it took me a while to realise it had stopped and so by then the larget had past the meridian

[Bob Denny]

I really don't know what I can do with this Peter, I am sorry.

[Peter Brackenridge]

Hi Bob

Just to let you know I worked out what the problem was. There is a yellow line in The Sky X called Telescope Limit. For some reason this line was in a position that was not at the meridian but over by 0.33 Ha, on the east side of the meridian. So when the mount moved the telescope to that position it would produce this error. I had forgotten that some time ago I had this problem and had been helped on the Bisque forum as I had noticed it but didn't know how to move it . So now I have just dragged it by a little square that is attached to part of the yellow line, to the meridian, and now I think things are working okay again, well so far.

Peter