Hi,
I am playing with the idea of getting a bigger chip for my Mewlon in order to reduce my resolution from 0.245”/px to 0.45”/px.
What is the opinion of the experts how to bin correctly.
I know binning with CMOS chips is not that elegant as binning with a CCD chip.
Is it worth or do I get more trouble then efficiency?
Thanks for you ideas and comments…
Rainer
Hi,
from a CMOS perspective I would always BIN (or “resample”) in post processing. There you can decide how much you want to resample based on your image "FWHM” and gain SNR.
You can check out if you’re under-, well or oversampled with RC Astro’s MTF Analyzer: https://www.rc-astro.com/mtf-analyzer/
If your image FWHM is in the rough ballpark around +-3 pixels you are well sampled and you do not have to bin. Just check out your subframes in Pixinsight with the tool “FWHMEccentricity” and measure the median FWHM of your stars.
Regards
Tobiasz · Nov 30, 2025, 06:24 PM
Hi,
from a CMOS perspective I would always BIN (or “resample”) in post processing. There you can decide how much you want to resample based on your image "FWHM” and gain SNR.
You can check out if you’re under-, well or oversampled with RC Astro’s MTF Analyzer: https://www.rc-astro.com/mtf-analyzer/If your image FWHM is in the rough ballpark around +-3 pixels you are well sampled and you do not have to bin. Just check out your subframes in Pixinsight with the tool “FWHMEccentricity” and measure the median FWHM of your stars.
Regards
Thank you. will take a look into it and try to understand it.
quote:”If your image FWHM is in the rough ballpark around +-3 pixels”
Is this valid for any focal length?
Rainer Ehlert:
Hi,
I am playing with the idea of getting a bigger chip for my Mewlon in order to reduce my resolution from 0.245”/px to 0.45”/px.
What is the opinion of the experts how to bin correctly.
I know binning with CMOS chips is not that elegant as binning with a CCD chip.
Is it worth or do I get more trouble then efficiency?
Thanks for you ideas and comments…
Rainer
Rainer Ehlert · Nov 30, 2025, 07:37 PM
Tobiasz · Nov 30, 2025, 06:24 PM
Hi,
from a CMOS perspective I would always BIN (or “resample”) in post processing. There you can decide how much you want to resample based on your image "FWHM” and gain SNR.
You can check out if you’re under-, well or oversampled with RC Astro’s MTF Analyzer: https://www.rc-astro.com/mtf-analyzer/If your image FWHM is in the rough ballpark around +-3 pixels you are well sampled and you do not have to bin. Just check out your subframes in Pixinsight with the tool “FWHMEccentricity” and measure the median FWHM of your stars.
RegardsThank you. will take a look into it and try to understand it.
quote:”If your image FWHM is in the rough ballpark around +-3 pixels”
Is this valid for any focal length?
Image FWHM depends on several factors, which is seeing, focal length and pixel size. So yes, focal length is a factor. More focal length gives you more reach and finer sampling.
Regards
andrea tasselli · Nov 30, 2025, 07:40 PM
*For anything but the best seeing Earth can offer that image scale is wasteful
Hi Andrea,
Do you mean I am exaggerating with 0.245”/px?
one of my images with 0.245”/px
https://app.astrobin.com/u/NHSA_Observatory?i=0njoij&r=B#gallery