Can I do SHO Narrowband Imaging using a DSLR using the inbuilt monochrome setting in the manual mode? - Forums

Topic starter

May 17, 2022 · Edited: May 17, 2022

Hi all,
I know this may be silly of me to ask! Can I really do SHO narrowband imaging using a Canon 90D?

I do know that dedicated monochrome cameras are far better than DSLR/mirrorless cameras anytime. The reason why I'm asking is because I came across a post through SkyWatcher USA's post on Instagram, the person has used modified Sony Alpha 7 R Mark iii camera with 3nm SHO filters to capture deep sky objects and the pictures have come out very good.

I'm still not into astrophotography yet, shall start soon once I've purchased all the equipment. I was just curious to know about it!

Respectful Engaging

Hornisse

May 17, 2022

https://www.astrobin.com/groups/66/dslr-narrowband/

kuechlew

May 17, 2022

To add a bit of explanation to Hornisse's link:

a) Yes you can do narrowband imaging with a DSLR. The narrowband filter - usually Ha, Sii and Oiii - will let a small part (typically 3 to 12 nm) of the spectrum pass to the sensor of your DSLR. Please note that a DSLR sensor is usually less sensitive to the red part of the spectrum compared to an astro modified camera, so you will need a longer integration time - in particular for the Ha signal.

b) There is no need to use the monochrome setting of your camers and it doesn't improve your result to do so. It may even be harmful. Usually the monochrome mode of a camera provides you with an 8 bit grey scale JPEG while a raw file is typically 12 bit or more and uncompressed. You lose 4+x bit of information and you may have to fight with compression artifacts. So just stick to the raw file.

While OSC camers suffer from the drawback that only part of the sensor captures the frequency permitted by the narrowband filter, on the positive side you may use dualband filters to capture Ha and Oiii in one image.

Good luck and clear skies
Wolfgang

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andrea tasselli

Frequent contributor

May 17, 2022

While OSC camers suffer from the drawback that only part of the sensor captures the frequency permitted by the narrowband filter, on the positive side you may use dualband filters to capture Ha and Oiii in one image.

Or SII and OIII

Lynn K

May 17, 2022

Using a mono settings on a color Bayer array CCD/CMOS sensor will have no avantage. The Bayer array is still in affect and only 25% of the pixels will allow the red spectrum to be recorded. 50% of the pixels will be responsive to the Green spectrum and 25% will be responsive to the blue spectrum. SII is in the red spectrum and will have the same limitation as Ha. OIII will be received by both the green and blue filtered pixels. To what percentage, I do not know. That will depend on the CCD/CMOS EQ.

You may have a misunderstanding of how the Bayer array is applied to a CCD/CMOS chip. Appling a mono software appliction in a DSLR or comuter software, only desaturates the color. The color Bayer array chip still filters the color spectrum the same.

Yes, you can put anarrow band filter in front of a color Bayer array chip. But, that is not what a color chip was designed to do, and will have sinificant limitations. You have to realize that most color chips used in AstroPhotography cameras, where not designed for that purpose. Astro manufactures have adapted those chips to suit the Astro market. The Color Bayer array chips are aimed at a imager wanting convenience and to avoid the cost of filters.

Lynn K.

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