FITS roworder support?

I'm not sure but is roworder a standard keyword for the Fits specification?

@vincent-mod It's not, but then again the FITS spec itself has very few keywords explicitly defined in it.  Many of the commonly used keywords (even ones like RA / DEC) are defined in agency-specific dictionaries and not in the core spec.

I have searched here and found release notes saying ROWORDER is supported in APP, but yet it doesn't appear to work, hence my puzzlement.

Right, I'll ask Mabula about it. Please note that we're away to Astrofest in London (Mabula from 29-01 and me from 02-02), I hope I can get an answer before that for you.

Is there any news on this, please?

Not yet unfortunately, Mabula is unavailable at the moment. I'll make sure he gets to the posts when he is.

Hi Ray @raybellis,

The Fits roworder keyword is fully supported in the latest APP version.

The keyword actually indicates how data with a Bayer Color Filter Array should be debayered. It does not indicate that the image should be shown upside down I think. Depending on the ROWORDER being bottom-up or top-down an inverse Bayer pattern should be use to correctly debayer the data.

https://free-astro.org/index.php?title=Siril:FITS_orientation

Mabula

Hi @mabula-admin  !

I believe it's strictly intended to address both.  It happens that Siril always (and IMHO incorrectly) assumes bottom-up for display purposes, but other applications (e.g. PI) do the "right" thing both for Debayer and for display in the presence of the keyword.

As written in the portion of the FITS specification that was quoted in the above link:

we recommend that FITS writers order the pixels so that the first pixel in the FITS file (for each image plane) be the one that would be displayed in the lower-left corner

yet APP always loads and displays the image data such that the first pixel is displayed at top-left.

Ray

Hi Ray @raybellis,

Okay, I will check this behaviour 😉 and fix it then.

It would help me if you can share 1 or 2 of your light frames with me, simply for testing purposes.

Can you upload a couple of frames here:

https://upload.astropixelprocessor.com/

username: upload

password: upload

Please make a folder with your name and issue like: RayBellis-FITS-ROWORDER

and let me know once uploaded 😉 then it will be easy to correct.

Mabula

@mabula-admin I've uploaded two files into RayBellis-VesperaFITS

img-0001.fits is the file straight off the scope (a Vaonis Vespera smart scope).  It's bottom-up data (per FITS recommendations) but doesn't say so.

light-0001.fits is the same file with the FITS headers cleaned up for conformance.

thanks!

Ray

Thanks Ray @raybellis,

Willl keep you updated 😉 !

Posted by: @raybellis

↑

@mabula-admin I've uploaded two files into RayBellis-VesperaFITS

img-0001.fits is the file straight off the scope (a Vaonis Vespera smart scope).  It's bottom-up data (per FITS recommendations) but doesn't say so.

light-0001.fits is the same file with the FITS headers cleaned up for conformance.

thanks!

Ray

Hi @raybellis,

I have fixed this now. FITS images with the ROWORDER tag BOTTOM-UP will also be displayed BOTTOM-UP. I have made sure that calibration is not affected, old calibration masters will still work properly. 2.0.0-beta14 will have this fix and I will probably release it within a couple of days 😉

Mabula

Great, thanks!

Ray