Yeah, I'm considering options for approaching this issue. CR2/DNG/ARW cannot be subframed. It might be possible to open the file, convert to jpg, subframe, then upload, but that would take too much time as well. GPhoto driver already process all formats to FITS, and even if I wanted to display CR2 within FITSViewer, I'd have to use libraw to convert to JPG, then load it in FITSViewer and lose all the FITS header info that might be useful.

I'm thinking this: Use FITS for focus/guide/alignment and RAW for capture. What do you guys think?

I guess it would be possible to modify dcraw or libraw to support decoding only a part of the full raw image (maybe at MCU granularity or something), which might speed things up downstream. Also support for the smaller raw formats could be useful for some cases and kind of emulate binning modes (for example Canon's sRAW is 1/4 size of the full image, mRAW is a more complex downsampling) and should be enough for alignment and probably also for focusing and guiding. Even switching to JPEG might be acceptable for those.

This will be perfect for me if the selection FITS/ARW could be made automatically be ekos

You need ARW file again for your test?

With libraw, you can decode a RAW file and then copy its data (or part of it), but then you'd have to save the subframe back as the original format (CR2/NEF..etc) which I don't think it's possible with libraw and even adds more overhead. Currently, after libraw decodes the RAW images, it is subframed if necessary and saved in FITS. libraw frames are always 16bit which might explain why its size is overall larger as some cameras are 10, 12, or 14 bits so it went for 16 to cover all.

I dug a bit deeper and it seems lossless JPEG doesn't offer a handy boundary to do partial image decode like lossy JPEG does as MCU so that point is moot. Canon's CR2 is lossless JPEG encoded internally so the data is smaller compared to raw 14 bit (or 12 with some sensors) data, even though it does have JPEG previews and other metadata embedded.

Yes it's good to have it here in case I need it for testing in the future.

ok.

here is a ARW file of M45.

4256x2848
8.4 um pixel size
420mm focal length

Ok it's done. It should switch to FITS when doing focus/align/guide and use FITS or Native (depending on your selection in Ekos options) when doing capture.

Hi Jasem,

i tried but now the files saved in capture module are always fits(i changed fits and native in indi control panel but the files saved are always fits).

Log files attached (see last file).

If you still need any files, I have probably hundreds of raw cr2 files. They are taken with various cameras, various scopes, and various objects. Do you still need any?

Canon Cameras: Canon XSi, Canon 60D
Scopes/Lenses: 12 inch f/4 Newt, 10 inch f/6 Newt, 6 inch f/4 Newt, Rokinon 85 mm Lens, Tamron 18-270 mm Lens, and Canon 10-18 mm Lens

You need to change settings in KStars Options --> Ekos --> Capture --> DSLR Format

Nothing required at this moment, thanks!!