Click to Recentre not behaving as expected

Fir Chlis · #1

Hi there

Does anyone else use Pixel Position /Click to Recentre? I'm still fairly new to Sharpcap so I don't know if it's user error or limitations of the procedure, but I can't get the clicked position to recentre.

I polar align using Sharpcap to less than 1 min of error. Goto and sync on my setup are almost always very good, with the target ending up in the centre of the FoV and I'm getting good Live Stacking images, but occasionally a target is not centred, so I've tried the Click to Recentre, but the target doesn't end up in the centre of the FoV, and sometimes disappears out of view.

I don't currently have any live images, but I was able to reproduce the problem using Sky Simulator, to illustrate the issue.

Pictures show M82 after a Goto/Sync, I then select the star above right and double click to recentre, and the result is shown in the third image - the white cross is the FoV centre, and the star is circled. This isn't too bad, but under live conditions, the target sometimes ends up out of the FoV completely.

I'm using SharpCap 4.1, latest release, on a Skywatcher 200PDS with HEQ5 Pro. As far as I can tell, everything is using J2000.

Cheers

Geoff

#2

Hi Geoff,

let me test and check - I haven't used it for a while (tend to use plate solve/resync to recenter), so it could have been broken by something.

cheers,

Robin

Fir Chlis · #3

Hi Robin

Thanks for the quick response. I would normally just do a plate solve /sync again, but on the few occasions when the target won't centre, I've tried the recentre. The attached image shows the first occasion (29 Jan), when I was trying to get the head of the Horsehead Nebula (neck of horse is inverted at lower left of image). The image is the result of the plate solve/sync, but I couldn't get the head to centre in the FoV.

Cheers

Geoff

#4

Hi,

just tested the exact same situation in Sky Simulator and I'm not having any issues...

: Screenshot 2024-02-10 140217.jpg (534.18 KiB) Viewed 446 times

What plate solving option are you using in SharpCap? Can you share the SharpCap log from your sky simulator test so that I can see how the results differ from my testing.

thanks,

Robin

Fir Chlis · #5

Thank you - so it may well be something in my configuration.

I'm using the Sharpcap plate solver with the 0.25 degree index, and if it's of use, my FoV is I think fairly small - around 38' x 22' - but I do get good polar alignment and plate solving.

I've attached two log files, the one from today using Sky Simulator, but I've also located one from the other night when I was testing this issue out on Deneb in a live session. There are two instances of Deneb in the log file from 8 Feb. I'm pretty sure the first (around 18:23) was for focusing, but the one at around 19:38 was when I was testing the recentre - and seeing the issue. If needed I can have another go with screenshots - if another clear night eventually appears.

Similar to comments from other users, I'm delighted with SharpCap Pro in my initial steps to move from visual observation to EAA - it certainly beats the cold and discomfort whilst trying to see a faint fuzzy blob.

Kind regards

Geoff

Fir Chlis · #6

A further update this morning.

The issue originally occurred on the laptop that sits under the scope during live sessions, and is the one that originally exhibited the problem during a few live sessions.

The laptop that I used for demonstrating the problem yesterday using SkySimulator is the one that stays in the house, and uses VNC to connect to the scope laptop.

I've just installed SkySimulator on the scope laptop and the Click to Recentre behaves exactly as expected, but the indoors laptop is still showing the issue with SkySimulator.

Maybe the best thing will be to do a live test next time there's a clear night and post screen shots and log file from the live session. Though it's odd that two different laptops have shown the issue, albeit one with a real telescope and one with a simulator.

Geoff

#7

Hi Geoff,

thanks for sharing the log - I have had a dig into them and can find the information relating to the recenter - the section of the log is below

Code: Select all

Info   	19:40:15.758861	#1 	MessageBox : 'Confirm Mount Movement' Move the mount to place this position (RA=20:41:12,Dec=+45:16:58) in the center of the image? => user choice Yes					in DialogResult SharpCap.Base.Utilities.MessageBoxHub.ShowImpl(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defaultButton)
Warning	19:40:15.759456	#1 	MessageBox: Move the mount to place this position (RA=20:41:12,Dec=+45:16:58) in the center of the image?				in DialogResult SharpCap.Models.Application.ShowMessageBox(string message, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton)
Warning	19:40:15.760571	#1 	MessageBox: User Chose:Yes																								in DialogResult SharpCap.Models.Application.ShowMessageBox(string message, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton)
Info   	19:40:15.761589	#1 	About to center pixel at {X=1913, Y=851}, calculated to be at RA=20:41:12,Dec=+45:16:58 (J2000)							in bool SharpCap.Models.PixelPositionProvider.SlewToWithConfirmation(PointF point, string name)
Info   	19:40:15.762322	#1 	Plate solve center was at RA=20:42:11,Dec=+45:20:29 with mount at RA=20:41:24,Dec=+45:15:29, offsets (-0.013029175030720097, -0.08333290638996971)				in bool SharpCap.Models.PixelPositionProvider.SlewToWithConfirmation(PointF point, string name)
Info   	19:40:15.764177	#1 	Calculated goto location RA=20:40:25,Dec=+45:11:58 (J2000)

The second attempt shortly after is here

Code: Select all

Info   	19:40:57.038117	#1 	MessageBox : 'Confirm Mount Movement' Move the mount to place this position (RA=20:41:24,Dec=+45:16:06) in the center of the image? => user choice Yes					in DialogResult SharpCap.Base.Utilities.MessageBoxHub.ShowImpl(IWin32Window owner, string text, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defaultButton)
Warning	19:40:57.038500	#1 	MessageBox: Move the mount to place this position (RA=20:41:24,Dec=+45:16:06) in the center of the image?				in DialogResult SharpCap.Models.Application.ShowMessageBox(string message, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton)
Warning	19:40:57.038863	#1 	MessageBox: User Chose:Yes																								in DialogResult SharpCap.Models.Application.ShowMessageBox(string message, string caption, MessageBoxButtons buttons, MessageBoxIcon icon, MessageBoxDefaultButton defButton)
Info   	19:40:57.039251	#1 	About to center pixel at {X=1465, Y=2079}, calculated to be at RA=20:41:24,Dec=+45:16:06 (J2000)						in bool SharpCap.Models.PixelPositionProvider.SlewToWithConfirmation(PointF point, string name)
Info   	19:40:57.039797	#1 	Plate solve center was at RA=20:42:11,Dec=+45:20:29 with mount at RA=20:41:24,Dec=+45:15:29, offsets (-0.013029175030720097, -0.08333290638996971)				in bool SharpCap.Models.PixelPositionProvider.SlewToWithConfirmation(PointF point, string name)
Info   	19:40:57.040115	#1 	Calculated goto location RA=20:40:37,Dec=+45:11:06 (J2000)

Both look reasonable - the click co-ordinates are close to the catalog co-ordinates for Deneb and the calculated positions seem to include the offset between the plate solve center of view and the mount co-ordinates recorded at plate solving.

However, I am noticing that you have done a solve and sync just before that, which included correcting an offset of 0.02 degrees (about 1 minute of arc). I wonder if somehow the book-keeping data for the plate solving is incorrect after the solve+sync (neglecting to include the sync offset has changed). If that was the case then you might expect to see the problem if a solve+sync was the most recent plate solving action, but not if a simple 'solve only' was the most recent. SkySimulator might show a similar problem if the option to enable a polar alignment offset was enabled.

Some things to think about - I will try a test too if clear skies allow.

thanks,

Robin

Fir Chlis · #8

Thank you for the informative reply. I’ll see what I can find out on the next clear night, looking at sync/not sync.

Geoff

Fir Chlis · #9

I managed an hour last night between clouds to do some more testing on the Click to Recentre issue I’ve been having.

Start Sharpcap and do polar align – good alignment
Info 19:18:54.327802 #26 Longitude=-7.025833333333333, Latitude=57.83388888888889, FrameOffset=-9.818787,-17.640625, CenterOfRotation=RA=23:54:22.9,Dec=+89:51:50, AltAzCor=Alt=+57:52:45,Az=359:45:33 AltAzPole=Alt=+57:52:53,Az=359:45:50, AltAzOffset={X=0.002505496, Y=0.002222324} in PointF

Close and restart Sharpcap (to keep log file small), goto /sync /recentre Capella. Capella was out of FoV after goto, but nicely centred after the automated recentre.