Binned colour

[martin_h]

I know this is looked upon by some as a sin.... but I'm new to this LRGB lark and willing to try anything once.....

So, assume I've got my binned RGB now what? Do I stack them in say DSS then "un bin" them to match the L frames? or do I "un bin" them first, then stack etc?

Also - if I stack them first, will 2x drizzle in DSS bring them back up to size?

Or what?

And also do the calibration frames need to be binned as well to match?(assuming I register and stack the binned images)

What do you lot do?

[roundycat]

First off, only bin if you are down in the read noise and it is a problem. If you can manage long enough exposures to be sky limited you do not need to bin. It will cost you spatial resolution and the result, compared to unbinned, is ugly. You may well get away with it if using a large aperture scope (think 12") but normal scopes do not have resolution that you can throw away. I have pictures of the Rosette in nb somewhere that prove it.

Obviously they all need to be the same size, darks should be binned or they will be invalid, flats can be left unbinned so long as the cal frames match the lights for size and filter. I re-sized before stacking but do not bin now as the losses outweigh the gains. Just take longer exposures and put up with the time it takes. Equal exposures with each filter, tons of Lum will wash out the colour.

Dennis

[Whippy]

If you do bin your colour, stack and combine them as normal and then all you do re-size the RGB image to match your luminence.

Tony..

[PortableAstronomer]

When I did mono-CCD imaging I binned the RGB 2x2 then used drizzle in DeepSkyStacker to get back to the same resolution of the luminance.

Drizzle is more sophisticated than re-size after stacking, that's why I used it. You will end up with less 'blocky' RGB frames.

But in practice I doubt you will see much difference because the luminance is still unbinned and the resolution of the RGB isn't so noticeable when you combine it.

[ollypenrice]

When I did mono-CCD imaging I binned the RGB 2x2 then used drizzle in DeepSkyStacker to get back to the same resolution of the luminance.

Drizzle is more sophisticated than re-size after stacking, that's why I used it. You will end up with less 'blocky' RGB frames.

But in practice I doubt you will see much difference because the luminance is still unbinned and the resolution of the RGB isn't so noticeable when you combine it.

No one is talking about focal length. I would say the longer iit is the more you can get away with binning. For me the price is to paid in terms of the star quality. I have entirely stopped doing it for myself but if folks here want to rattle off more images then I recommend it as a time saver. The drizzle idea is worth a go so thanks for the idea, Portable!

Olly

[Whippy]

Hm, I normally stack everything including the colour with 2x drizzle as a matter of course anyway so I still have to resize regardless!

I hear what you're saying about focal length Olly, I did bin a couple of times with my ZS66 and it didn't work more often than not but TBH, when I decided I wasn't going to bin the colour, it didn't matter what the f/l was.

Tony..

[martin_h]

The only reason I asked in the first place was....errrr.....I accidently left the binning on after I used it to grab a frame to check allignment...so I was left with a nights worth of images that were either worthless or could be salvaged...oops.

My M1 in the deep sky imaging section is the result!

[ollypenrice]

The only reason I asked in the first place was....errrr.....I accidently left the binning on after I used it to grab a frame to check allignment...so I was left with a nights worth of images that were either worthless or could be salvaged...oops.

My M1 in the deep sky imaging section is the result!

Re shoot a luminance layer in Bin1?

Olly

[martin_h]

LOL. Didn't even think of that one!

Ahh well It's all done now, I might go back to it at some point and add some more( I want to add some Ha and see what that does to it)

This imaging lark is fun isn't it?