There is some clear weather forecast in a few days and I'm going to attempt M81 & M82 LRGBHa with my new(ish) ZWO ASI1600MM-Pro, I imaged them around this time last year with a DSLR.
I'd like to try to get some of the IFN and in other posts it looks as though it's possible from Bortle 5.
Would a good approach be HDR; shoot usual L exposures to get a median ADU of 400 at 0 Gain, probably around 30s from experience, but then get some longer L exposures for the IFN?
Is it also worth getting longer exposures for R and B as well as the usual for median ADU of 400? I read that IFN is faint red emission and faint blue reflection.
IFN sits right above the noise floor, alot of people will pick it up in a light polluted area but do not know its there.
Also, if you are not taking phenomenal perfect flat frames, it will never work. If you hide vignetting or background issues by keeping the background extremely dark, you will never reveal the IFN.
Study the region that you want to shoot closely and pick out the brightest part of the IFN, try to image it near Zenith, and make 100% sure that you have good transparency or its going to be much more difficult, having light pollution is one thing but trying to image through bad transparency with light pollution is a disaster, you will pick up the galaxies but not the IFN.
The challenge is 50% processing and 50% acquisition conditions.
The area near the star 24UMa is pretty bright, I believe the Mandel Wilson catalog refers to it as the Volcano nebula.
I think you could pick this up in a light polluted area under ideal conditions, the image below was captured at a Darksite, but I
am pasting this in to point out the brighter portion of this nebula.
M81 and M82 IFN from Monochrome 60d by Wes Schwarz, on Flickr
Edited by calypsob, 21 February 2019 - 11:32 AM.