NGC 2903 In Leo

Impressive shot there of an (I assume) very difficult target.

Thanks for the kind comments Seanie. The duration is at the bottom left of the image LRGB 90:40:40:40. All 2 minute subs unguided.

Dave

If I can be a pinickity devil here - the information to the bottom left doesn't state units. Context, for the experienced, should make sense of it but units should always be stated, in my humble oppinion.

While I didn't end up in a science discipline, the idea of stating units was so well impinged on me when I studied science, that I cringe, for example, at weather forecasts (or Discovery programs) that ommit them.

Pinicketiness aside; A fabulous image. And a question - is there a methodology whereby the RGB is a certain percentage of the luminosicty capture or what?

For example, your L frame was 90 minutes and each of the RGB frames were 40 minutes. That is slightly less than half exposure time - is there methodology to that?

Mark

mjc wrote:

For example, your L frame was 90 minutes and each of the RGB frames were 40 minutes. That is slightly less than half exposure time - is there methodology to that?

Yes Mark, the accepted norm is that each of the RGB channels should be the same length as the Luminance however by binning 2x2 you can cut each channels integration time in half. In reality you go and get as much data as you can and often have to make do with something less than optimal. I have found that binning the RGB doesn't affect the final image in the slightest.

Thanks for your response Dave.

If you were to bin 1x2 (or 2x1) I would follow your line of thinking. However you binned 2x2 (unless that was a typo) and that implies that you can cut the RGB time to one quarter for same SNR (photon capture linearly proportional to pixel surface area). As it stands you have a higher SNR in the colour channels than in the L channel.

Would it not be a better investment to have increased the integration time in L and bring back the RGB further?

Don't get me wrong I cant fault your image - ust trying to refine my understanding of this LRGB thingy.

Mark

Hi Dave,

Well done on a fine image. I have never tried color capture at 2X2 binning due my inexperience with the art of resizing the the 2X2 to fit a Luminance binned 1X1.
Anyway great detail and great H Alpha regions.

Carl.