FMW Returning incorrect coords on adjacent frame . .

See attached screenshots. Problem is FMW returns correct coords for only one of the two frames in the mosaic. Never had this problem before. Checked and it is occurring on two computers. SGPv.
In this case Frame 2 should be approx 20-25 arc mins different in dec than frame 1. Yet FMW coords are only about 1.5 arc mins different. Seems this is not general. Trying a different target yields correct results.

I have been having the same problem on a 3 panel mosaic of M8 to NGC 6559 and nothing seems to make any difference. I even prepared the mosaic co-ordinates with other tools like PixInsight Mosaic planner

After getting around the default object co-ordinates often but not always being significantly off (I get the correct RA and DEC from Stellarium and use that) the subsequent frames of the mosaic are typcially 1/3 of the frame offset and need to be rotated to get them aligned which looks messy and effectively doubles how mnay frames I would need to shoot to get the enitre field.

My guess is co-ordinates and angles for the subsequent frames of the mocaic are being shifted (J2000 now vs JNow?).

This has never happened before but I haven’t shot mosaics in a while. I rolled back to a few SGP versions with no luck.

It looks like a problem with angle and offset but I tested and reset the rotator with no luck.
I am using the latest version of ASTAP for solving.

Something seems to have changed as the FMW used to work every time no issues so I am very interested in finding out how this problem is resolved.

It sounds like your problem may be different from mine?
I have been using the FMW for several years. And on the same v. of SGP. Never encountered this before.
No explanation, just an observation. It has only occurred on this single target. And it has occurred on two machines, ruling out AFAICT, any setting I’ve somehow goofed up.
As far as “something seems to have changed,” I am at a loss as I’ve changed nothing.
Guess I can live with it so long as it doesn’t start munging up on other targets too.

We’d need to do more research here. SGPro uses a series of services to resolve coordinates and so, if something has changed with these services, then changing versions of SGPro would yield the same results.

@Terry or @IanParr

Do you have logs showing creation of this mosaic? I’d be curious to see if it has errors or issues with the primary service, is falling back to other services, etc.

Further guidance is here:

In the meantime, I will see if I can reproduce the barnard150 issue shown above. Maybe this is a math issue that has been present for a very long time and never reported?

Actually @Terry maybe I’m confused. I reproduced the situation you described above and did indeed get the same results. That said, they seem accurate to me, but maybe I’m confused (a common state for me).

In the canvas you have posted above, we expect the DEC to vary almost insignificantly right? Isn’t the difference between those 2 frames is almost all accounted for in RA?

Since you have these frames stacked atop one another and the canvas rotated 90 deg, it seems we should see an insignificant change in DEC.

In your screenshots, we do see a nearly 4’ of RA separation between the two frames which seems reasonable.

Hi Ken

Thanks for the quick response.
Yes, with a clear night I will document a systematic run through the process along with screen shots and the logs and lodge a proper support request. That said I cheated and solved the problem by getting a RedCat 71 and APSC CMOS camera that returns a 6x4 degree FOV :slight_smile:

Hi Terry
Thanks for raising your issue as it got me moving with mine.
Astrophotography … what a hobby! It needs clear nights, deep pockets and a high threshold of pain.
Good luck

Hi Ken:
Well, my head now hurts from trying to figure this out. This is going to be embarrassing!
You are correct that 4mins in RA, or about 1 degree of arc seems correct. I have to retract my assertion that the FMW was returning incorrect values.
This situation arose when I switched from frame 1 of the mosaic to frame 2. Next morning I saw the frames were near identical. It’s as if the mount did not slew when frame 1 completed and frame 2 began. Oh, oh! Going back and looking at the sequence, I can verify my blunder. I had left “Do not move to location” selected! A rookie error for sure! I am glad that my faith in the FMW is restored and I apologize for plunging down a rabbit hole into seeing error with the FMW where there was none. May Ian’s problem be so easily solved.

Doesn’t the FMW automatically check the “slew to and center” boxes?

Optionally. This, however does not prevent modifications to those settings later.