Acquiring mono RGB data over the city - Forums

Topic starter

Aug 6, 2019

Total newbie here. I have a mono camera and a filter wheel. First light was an underexposed OIII stack of M 16, 3 days ago. Well, first light was actually 90 minutes of Ha the day before, but so out of focus to be useless! ooops.

I have the advantage of shooting over the ocean (to the south) for most of my targets, so the city isn't an issue.

I put shooting the Veil on my to-do list.. I was thinking Ha, OIII, and then an RGB set for the stars. Is there a trick to getting the stars when shooting over the light polluted city?

I know the NB filters are ok, but how does one deal with 100nm wide filters over Los Angeles?? I do not have a light pollution filter so I assume I need a trick to get the SNR way up.

Engaging

Carastro

Aug 9, 2019 · Edited: Aug 9, 2019

I live in the suburbs of London, and find LP a real pain. However I have achieved a fair bit with narrowband and in the early days with a DSLR, mainly the brighter targets. I tried last year to add RGB stars to NB images, and it does seem to work OK.

I made up a personal website of images I have achieved for Bortle 8, this may give you some idea:
https://sites.google.com/view/carastroimaging/homePlus I don't have an ocean to the south of me. Only more town and LP.

Re LP filter, of course you could get one, I have one but I often forget to use it and I don't think a LP filter was used on all the Mono shots on the website above.

Hope this helps

Carole

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bobzeq25

Aug 11, 2019 · Edited: Aug 11, 2019

My "trick" (used by almost all serious imagers) is gradient reduction in processing. It's surprisingly effective. Example. RGB data. No other processing besides a simple stretch, necessary so you can see the linear data.

https://astrob.in/420460/0/

https://www.astrobin.com/420461/?nc=user

Red Zone, Bortle 7, mag per arc sec squared low 18s. You do need to do the total imaging time, this was 164X30" at F4.8.

Final image with H alpha added, giving the acquisition details.

https://www.astrobin.com/384117/G/?nc=user

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