GEM flip with Sitech controller

[Albert van Duin]

After using a 10Micron GM2000 mount for several years, I switched to a Mesu-mount 200. It is running very smoothly.

Flipping the 10Micron worked great, it could run for 5 degrees past the meridian, so no long waits around the flip point.

With the Sitech I cannot get it working this way, I have to set up Sitech and ACP like this to let it work without problems:

setting-0-sitech.JPGACP-0.JPG


This works great, but sometimes the mount is idle for quite some time, see the attached log file 20191230@161803.log

However I can set the Sitech to run past the meridian, so I set it to 5 degrees (and ACP to 20 minutes)

setting-5-sitech.JPGACP-20.JPG

Now the integration is finished while passing the meridian, then the program pauses for an additional half minute (2 minutes past flip point), and the mount flips.
After refocus, the mount starts a goto to the object, and then the mount flips back....
Please see logfile 20191230@182935.log

Is there anyone using a Sitech controller who can shed some light on this?
Thanks.

[Bob Denny]

What is the meaning of the "auto-flip" options? Also (separate issue) the guiding reversal switches? The mount should "act normal" like other mounts. Ideally the same as though it were using guider cables, but maybe N/S is the same on both sides of the meridian. I don't understand needing a reversal when looking EAST though. Possibly SiTech can help with those auto-flip and reversal settings when using with ACP? There are multiple people using the SiTech and ACP so maybe someone here can help as well.

[Albert van Duin]

Happy New Year Bob!

Thanks for your reply.
The Reverse Guide Mode switch is needed to properly autoguide after a flip, I found out this is the right option for my setup, guiding works perfectly before and after a flip.

I think I must have touched the "Auto flip track" switch when making the second screen shot, it is normally not set, and was not set during the tests (I checked).

The "GEM Auto flip Goto" tooltip states:
If set, then when asked to perform a Goto to the other side of the meridian, the mount will perform an automatic GEM filip.

The "GEM auto flip Track" tooltip states:
When tracking to the meridian limit, the mount will perform an automatic GEM flip. Otherwise it will stop tracking

In an older thread, you looked into the Sitech flip: https://forums.dc3.com/showthread.ph...ht=sitech+flip
It seems that when you allow to track through the meridian, the flip points shift as well.
That thread was about an older Sitech driver, I'm using the latest one: 0.95A

Thanks.

[Andrei Ioda]

Dear Albert,

Thank you for reaching back to me and Happy New Year to you too!
I tried a few different settings of Sitech-II and ACP for its optimal work, yet could not find the best resolution for them.
Unfortunately, the logic of Sitech and ACP programs do not work in tolerance, this is why I have decided to reset the settings to default.

Please find two screenshots of my program settings attached down below,
Thank you very much,

[Bob Denny]

Andre and Albert -- I would like to try to solve this problem. The SiTech should behave well and be manageable by ACP without problem, including being able to track past the meridian. ACP run logs contain tracing to help me detect meridian flip problems. To begin with, set the SiTech to always flip at the meridian. Test this with tiny slews east to west next to the meridian, then west to easy near the meridian. It should be flipping right at the meridian. Of course it will only flip when slewed right?

Once you are positive (!!) it is always flipping at the meridian, and you have ACP's setting "When slewing..." set to 0 as in Andre's upper image, now try to run. If it gets lost please save and post back here with the ACP logs.

What is in the ASCOM & Logging tab?

Finally the "GEM AutoFlip" ... what does that mean? What if those are off? Does that mean the mount will never flip? Or what is "manual flip"?

[Andrei Ioda]

Finally the "GEM AutoFlip" ... what does that mean? What if those are off? Does that mean the mount will never flip? Or what is "manual flip"?

This means that in the case of tracking and upon reaching the meridian, the mount will flip automatically (if GEM AutoFlip is on), or simply stop (if GEM AutoFlip is off) when it reaches the meridian.

[Albert van Duin]

Andrei and Bob,

Thanks for your replies. It is a nasty problem...

Thanks for the screen shots Andrei, It looks like our settings are almost the same, only you switched "GEM auto flip track" on.

Bob, this is what the mouseover tooltips in the Sitech driver say:

The "GEM Auto flip Goto" tooltip states:
If set, then when asked to perform a Goto to the other side of the meridian, the mount will perform an automatic GEM flip.

The "GEM auto flip Track" tooltip states:
When tracking to the meridian limit, the mount will perform an automatic GEM flip. Otherwise it will stop tracking

Please find the screenshot for the "ASCOM & logging" tab attached.

Previously I checked that the mount flips immediately after passing the meridian.
A GoTo command with a very small westward movement will flip the mount.

I noticed taht Andrei is using V0.92ge and I am using V0.95A of the Sitech driver.

I will do a new run with the preferred settings as soon as the skies clear, and post my findings afterwards.
Thanks.

[Bob Denny]

The "GEM Auto flip Goto" tooltip states:
If set, then when asked to perform a Goto to the other side of the meridian, the mount will perform an automatic GEM flip.

This would be a normal operation. Leave this option on.

The "GEM auto flip Track" tooltip states:
When tracking to the meridian limit, the mount will perform an automatic GEM flip. Otherwise it will stop tracking

This is surprising. I can't think of a reason for the mount to flip while imaging (tracking). So this option should be off. The other issue here (with it off) is that the mount is incapable of tracking past the meridian. It's the only control system I have seen that has this limitation. I want to double che3ck this because it seems like a severe restriction.

If the mount truly flips at the meridian, and if the mount cannot track past the meridian, then the settings for ACP should be this:

Snap5.png

Note the negative numbers. This tells ACP to give it 2 minutes "safety" before its "tracking hard stop" at the meridian. You will lose time around the meridian, with ACP waiting until your target crosses the meridian and you have a full requested exposure interval in front on the west side. If you are taking 10 minute exposures, it will wait up to 12 minutes at the meridian.

[Bob Denny]

This means that in the case of tracking and upon reaching the meridian, the mount will flip automatically (if GEM AutoFlip is on), or simply stop (if GEM AutoFlip is off) when it reaches the meridian.

These two things are surprising to me.

• With auto-flip on, while capturing photons, just tracking, the mount will flip? Amazing.
• With auto-flip off, the mount cannot track past the meridian at all?

See my reply to Albert. I'll double-check. I want you guys to be happy.

[Albert van Duin]

Hi Bob,

Finally had some clear skies and time to test last week.
I set Sitech and ACP all neutral like this, with GEM auto flip goto ticked, otherwise the mount just stops at the meridian:

Sitech.JPGACP.JPG

I started imaging NGC869 which at the time was approaching the meridian, and after the first image the flip went well after a 317 second pause.
Please see the attached log.
It looks allright to me, I only can't explain the message after the slew at 18:08:36

18:08:36 Excessive pointing error, request pointing update for next target

The previous plate solve said:
18:08:30 Pointing error is 0.085 arcmin @ angle 231.03

Sitech includes a rudimentary planetarium program, SkyView.
On the attached image you can see the vertical blue dotted line on the meridian, that's where it flips.

The problem is that when I change the flip zone, the flip is postponed until the telescope points past that line.
What I would like is having the mount flip whenever a GoTo is started within a 5 degree region after the meridian.

Which settings would you like me to test now?
Thanks.