Processing Challenge 33 NGC7822

[STEVE333]

Hi @STEVE333 @Juno16

Sorry the data is giving you trouble. I'm away from my computer for a few days so cannot dig into it. I've no idea what could be wrong with the Oiii tiff.

On the fits, these were stacked by wbpp in PI. But remember this is a 2 panel mosaic, built using the Photometric mosaic process. I didn't do gradient reduction before PM but I guess that the process does do a fair chunk of processing in order to merge and blend the panels. Maybe that's the "embedded" stuff? The Ha and Oiii are simple channel extractions from the OSC mosaic and are what I used process to my final image. And I had no issues.

So again, apologies for this but I'm not sure what's gone wrong.

Nice final image though Steve and a nicely laid out processing map. Thanks!

Take care

David

No problems David. Sorry if it sounded like I was complaining. I just wanted to explain the problem I ran into in case anybody else had the same problem. Thanks for sharing your data.

The O3 tiff behaved very strangely. I believe it has something to do with quantization. When I ran ABE the Background image was very quantized with only 4 or 5 shades of gray across the image. If I changed the LUT to 24-bit it then had smooth gradients. However, when I looked at the ABE corrected image the quantization was still present. Changing to the 24-bit LUT didn't solve the problem. I'm a bit confused by this, but, I didn't have the same problem with the fits files, so, those are the ones I processed.

Thanks so much for providing both the tiff and fits files. A lot of work on your side!

Steve

Hi Steve, absoloutely no worries, I was not taking it as complaining in any way at all.

I've had a chance to look at the files now and see exactly what you mean - after ABE dreadful stripes!. Its very starnge and its there in all 3 of the tiff's. I tried saving a second time and it is the same so its not that those files are corrept. But then I tried doing the same with a recent non mosaic masterlight file and it had no issue after ABE when saved as a 16btiff

I've also saved masters (non-mosaic) for the challenge many times and never seen this issue. It seems it must be something happening when i save from PI to tiff after the Photometric mosaic process and may be associated with the embedded processing you mentioned. When I have more time I may dig in further and ask around the Pi forum too.

All very strange!!

rgds

David.

That's exactly what I saw! I've never seen it before either. Very strange indeed!

Cheers