Plate solving decanters target

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Eyeroll1952
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Joined: Tue May 25, 2021 2:03 pm

Plate solving decanters target

#1

Post by Eyeroll1952 »

I have seen the following issue addressed occasionally but have not seen a satisfactory answer…

Some of the time plate solving and centering on a target works for me but in most cases it doesn’t. I use an EQ6-R PRO mount and EQMOD, and use AstroTortilla for plate solving. What happened last night is fairly typical. I polar align and then tell the mount to go to Arcturus for alignment. In this case it put the star pretty much dead center in the camera. I then hit the plate solve button to see what it will do. It tells me the solve is successful but that I am off by 0.72 degrees. Consequently, it moves the mount to put the star at the bottom of the screen as seen in the picture. This sort of thing happens regularly but the degree if mispointing varies, sometimes it is off by several degrees. Incidentally, if you are trying to read the green bar it says the mount isn’t off much, but this was generated after I hit the plate solve button a second time so the numbers aren’t relevant.

Any suggestions for where to start looking for issues? (No need I think to debate JNOW vs. J2000 since that issue has been covered before on this forum and presumably shouldn’t be an issue.)

Thanks!

Paul
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Eyeroll1952
Posts: 8
Joined: Tue May 25, 2021 2:03 pm

Re: Plate solving decanters target

#2

Post by Eyeroll1952 »

Sorry, decenters... Decanters sounds like we're at at wine tasting...
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admin
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Re: Plate solving decanters target

#3

Post by admin »

Hi,

that's odd - particularly the size of the error being so large and being variable. The JNOW/J2000 mixup would only account for about 0.15 degrees maximum.

It may be worth checking the Alignment/Sync settings in EQMOD - it can be configured to use a complex pointing model, which may throw off the solve + sync (since the sync is not considered to be a 'this is the current co-ordinates', rather a 'here's another data point for the pointing model'). One thing you can try is to change the plate solve sync settings in SharpCap to 'Offset the mount to center the target', as this avoid the EQMOD sync complexity.

cheers,

Robin
Eyeroll1952
Posts: 8
Joined: Tue May 25, 2021 2:03 pm

Re: Plate solving decanters target

#4

Post by Eyeroll1952 »

Hi Robin,

Below is a screen dump of EQMOD after parking the scope. The first time this problem occured it was indeed an issue with the Alignment/Sync area; once I changed the “3-point + nearest point” to just “Nearest point” and reset the point count the issue went away, but this time it seems correctly set. (I must admit to not having a good feeling for what a lot of these parameters really mean…) If we ever get another clear night I will try your other suggestion.

Incidentally, this is likely coincidental (lucky me), but if I at any time tell Stellarium to sync with the mount it promptly steers off by what appears to be an even 90 degrees…

Paul
eqmod-may-2022.png
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Re: Plate solving decanters target

#5

Post by admin »

Hi,

nothing look badly out of place there, so probably worth trying the offset goto option if you get a chance. You could also try to capture and post here a full SharpCap log that includes a bad plate solving run - the log will contain all the info about things like where the mount was before plate solving, what the plate solve result was, what SharpCap sent to the mount, where the mount thought it was after the solving, etc - usually that is enough to work out what is going on.

No idea on the Stellarium thing - I really tend to only use Stellarium for the pretty pictures - SkyTechX is my preferred planetarium program for controlling the mount.

cheers,

Robin
Eyeroll1952
Posts: 8
Joined: Tue May 25, 2021 2:03 pm

Re: Plate solving decanters target

#6

Post by Eyeroll1952 »

Thanks. If this persists I'll capture a log file and upload. I'll look into SkyTechX as well. The only drawback is that I play on both Windows and Mac machines and SkyTechX is unfortunately only Windows.
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