New Feature : Drag and Drop into SharpCap

[admin]

Hi,

I don't see any of the CRVAL/CRPIX/CD?_? headers in your FITS file, which is odd - those should appear if SharpCap has plate solving information available.

Can you try this test please?

* Open SharpCap, select 'Test Camera 1' to show the default Orion Nebula image
* Select 'Plate Solve Only' from the tools menu
* Wait at least 8 seconds for the image progress bar to complete at the bottom right and the frame count to increase 1 at the bottom left
* Press the snapshot button to save the image as FITS
* Examine the FITS headers to see if you get the CRVAL etc headers.

I have just tested this in the same version you are using - 4.1.13584 - and I do see those headers appear.

thanks,

Robin

[T-Studio]

Thank you for your reply.

* Open SharpCap, select 'Test Camera 1' to show the default Orion Nebula image
→ Using the drag-and-drop function will display the image you previously dragged and dropped. (M42 was not displayed.)

* Select 'Plate Solve Only' from the tools menu
→ I did the same thing last time. (Note that annotations and other commands produce errors, so this command seems to be the only option available for PlateSolving.)

* Wait at least 8 seconds for the image progress bar to complete at the bottom right and the frame count to increase by 1 at the bottom left.
→ I received the same instructions last time, so I'm doing so now.

* Press the snapshot button to save the image as FITS.
→ I'm also doing this as instructed.

* Examine the FITS headers to see if you get the CRVAL etc. headers.

→ The headers I sent last time were not all included, so I'll enlarge the image and send it again.

No matter how many times I try, the WCS doesn't seem to be reflected when I open it in Aladin or similar.

スクリーンショット 2025-09-24 210711.png (67.04 KiB) Viewed 1315 times

[admin]

Hi,

interesting... Does the plate solve attempt succeed? I was presuming that it would, but maybe I am wrong. In particular I note that the co-ordinates in that header might be coming from a connected GOTO mount and therefore be causing problems (since they are nowhere close to the co-ordinates of the Orion Nebula image shown by default). Perhaps try without the mount being connected to avoid the wrong co-ordinates being used to guide the plate solve attempt.

I would also suggest an update to SharpCap - while the WCS headers should be in the version you are using, it's probably worth testing on the very latest so that you are using the same code that I have been testing with.

cheers,

Robin

[T-Studio]

Thank you for your reply.

I tried the following:

1. Update Sharpcap to the latest version

2. Remove the SkySimulator mount driver

Results
- Select Testcamera (DeepSky) from the menu → Instead of M42, the image I previously dragged and dropped appears (same as last time).

- PlateSolving ONLY → Snapshot after a few frames.

The Fits header changed slightly, but the location information still wasn't available in Aladin and other applications.

[admin]

Hi,

well, it now has the header information that I was expecting to be there which gives the mapping between the pixel co-ordinates in the image and sky co-ordinates. Unfortunately, maybe I was wrong to assume that was what Aladdin or other applications were going to rely on - it's not software that I have personally used.

It may be worth inspecting the headers of a file that works and comparing them with the one shown below that has the CD/CR info from SharpCap that doesn't work to see if there are any potentially relevant missing headers.

thanks,

Robin

[T-Studio]

Thank you for your reply.

I will send you the FITS header file I created using PlateSolving in another app.

This file will allow you to use the WCS information in Aladin and other apps.

[T-Studio]

The FITS header I sent earlier is the same JPEG that I previously PlateSolved using SharpCap.

Please use this to analyze the FITS parameters.

[admin]

Hi,

thanks for posting that - I wonder if it is the RADESYS header that is missing and causing the problem. The specification for WCS does suggest that it should be treated as a default of FK5 if the EQUINOX is 2000 and the RADESYS header is missing, but maybe the reading software just expects it to be present. I will try adding it as I can't see anything else that is missing.

cheers,

Robin

[T-Studio]

Thank you for your reply.

The FITS header file you sent was recognized by all of my WCS-using applications.

If you would like to make the changes, I will check it in SharpCap. (SharpSolver is the easiest to use on Windows.)

[admin]

Hi,

the version of SharpCap uploaded on Monday (4.1.13789) will write out the additional RADESYS header (and also includes the CUNIT2 header which was previously missing, although your file that worked had neither CUNIT1 or CUNIT2, so I think that is not critical). I was able to get the Linux tool 'xy2sky' from the wcstools package to correctly calculate sky co-ordinates for pixel positions based on the files created by that latest version.

Note that you will need to set the option to save FITS files in the 'bottom up' orientation in the saving settings to be sure of getting correct results - other applications may not understand the ROWORDER header that indicates the FITS is saved 'top down'.

cheers,

Robin