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Hi,
I have two mono cams from different FOV and filters and working through a process to make best of the data from them.
The filters are Antlia 3.5nm SHO from a Sharpstar 76, and Chroma 3nm SHO from a Sharpstar 107. A distint difference in quality and FOV, but useful nonetheless as I use the data for all my SHO images.
To start with I was doing a comparison of a Hubble 3 formula of each set of images/filters, registered to the same FOV and object, so I can use them both for a fair comparison.
The comparison is below straight after integration and combine tool:
Antlia 3.5nm SHO Hubble 3 from 76
Chroma 3nm SHO Hubble 3 from 107
All subs (each SHO) are 10 mins long x 5 and basic calibration, integration per filter and session and combined individually.
So far so good. But so I can do a fair comparison I decided to use APP to crop _before_ I combine in RGB tool.
I get different results. Can you explain why? Is it the autostretch because the extra black/non-DSO parts are not being included in the stretch?
Antlia 3.5nm SHO Hubble 3 from 76 Cropped then Combined
Chroma 3nm SHO Hubble 3 from 107 Cropped then Combined
From the first combine, uncropped, the comparison showsa bigger difference in colours, withe the Chroma being the closest to where I want to be before post-processing.
However from the cropping of the image to match each other's FOV before I combine, the data is slightly more subtle (still a difference, but they are closer matched).
What is the suggestion here on next steps -- do I use the cropped or uncropped data, and does it matter at this point if I save as a TIFF to post-process in say Adobe and do further colour balancing?
Hi @itarchitectkev,
Thank you for sharing this. I think the difference will be mostly from the normalization in the RGB Combine tool. Did you play with the normalization settings or not? The RGB Combine Tool by default will again normalize the input data, if you disable it, I think the results for cropped and uncropped will be the same apart from a slight stretch difference. So that means colors would be the same.
If you crop the data, then normalization parameters will be different leading to different outcomes.
There is no suggestion since both cropped and uncropped data will be the same in the linear base, it just depends on what formula preset you decide on and then tweak the formula. No formula preset will be ideal, they are just there as starting points. So need to transfer to Adobe if you would ask me, because then you will be forced to transfer stretched data, which is a big loss in flexibility in processing in my experience.
Mabula
