Search found 139 matches

by mAnKiNd
Thu Sep 13, 2018 6:17 pm
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

In Photometry there is a quantity called Airmass which is a function of zenith distance. Airmass affects the calculation of photometric magnitude by noting that the atmosphere reddens the color of a star. We can extend this to AP by frequently rerunning The Brain on the same rectangle of dark sky a...
by mAnKiNd
Thu Sep 13, 2018 6:14 pm
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

I feel that you are over-complicating things here - the Brain measurement needs to be run on something at least as dark as the darkest area in the field of view you are imaging - that will ensure that you get a gain/exposure combination that is not being affected by camera read noise. H Hi Robin, t...
by mAnKiNd
Thu Sep 13, 2018 2:04 pm
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

Thanks Brian, I might just go for unity then! I'm trying to consider what's best based on the fact that I won't be settling for a single 60 minite live stack, but will rather be doublestacking them plenty later. Question; After I've obtained my sky brightness value by pointing at a dark patch of the...
by mAnKiNd
Thu Sep 13, 2018 12:55 pm
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

Thanks Brian, Dialing in offset is indeed important, I ran into the same issue once where I didn't have any offset and my calibration frames did not work properly either. I noticed on my last run of the smart brain analysis that it automatically pushed my offset value to max, perhaps to avoid this s...
by mAnKiNd
Thu Sep 13, 2018 12:24 pm
Forum: Gallery
Topic: IC 5070 Pelican Nebula
Replies: 6
Views: 1110

Re: IC 5070 Pelican Nebula

Hi Dave, Thank you for the taking the time to explain your workflow, which sounds like textbook procedure and surely leads to great results, as you've demonstrated :) I can only add comments from my experience and hopefully I can be of help. I've followed a similar workflow as yours as well when tra...
by mAnKiNd
Thu Sep 13, 2018 1:42 am
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

oopfan wrote:
Thu Sep 13, 2018 1:17 am

I've decided that my next challenge will be SHO of a part of the Soul Nebula, specifically here.

My sensor's FOV closely approximates hers. It's nearly exact in the vertical dimension but my width is wider.

Brian
That sounds awesome! Go for it :)
by mAnKiNd
Thu Sep 13, 2018 1:41 am
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

Brian thanks. It's my understanding that if I were to use the smart brain (whose exposure setting analysis is based by default for a 1 hour stack) to figure out the best exposure & gain for each channel, say to achieve max. dr, then with that 'equilibrium between channels' in place, one could simply...
by mAnKiNd
Thu Sep 13, 2018 12:52 am
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

Or perhaps simply just use the smart brain on each channel for finding the max DR sky limited exposures, acquire calibration files and simply stop looking for unified settings, base it all on total integration time.
by mAnKiNd
Thu Sep 13, 2018 12:45 am
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

..though I'm not sure how one could keep the narrowband channel at the same exposure & gain/offset as the RGB channels and still get a decent single exposure histogram. Perhaps, treat the narrowband channel differently. Max DR for LRGB channels and a higher gain for the narrowband channels. If it's ...
by mAnKiNd
Wed Sep 12, 2018 10:45 pm
Forum: Deep Sky Imaging
Topic: sticky exposure length or sticky gain/offset for sky-limited exposures?
Replies: 41
Views: 4970

Re: sticky exposure length or sticky gain/offset for sky-limited exposures?

I always liked the idea of keeping gain, offset, and exposure the same. Not only do I get to reuse darks but I also get to set the exposure based on maximum light using the luminance filter. Having a full-well depth of a mere 15000 electrons makes me painfully aware of accidentally saturating stars...