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Efficiently using LRGB exposure time?

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#1 TodRiley

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Posted 27 October 2021 - 11:17 PM

I want to use my exposure time more efficiently owing to limited cloud free nights.  The common practice seems to be expose L for 50%, and RGB equally for the reminder.  Given that RGB exposures only provide color information and that L is the most important for resolution, what is the minimum ratio of RGB to L?   Knowing this will  allow me to maximize the time imaging with the L filter.   Thanks in advance.



#2 ks__observer

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Posted 27 October 2021 - 11:51 PM

Experiment.

I saw one very experienced imager ssy you can reduce RGB quite a bit.

You should also be using your RGB data to creat a synthetic lum with the L data.


Edited by ks__observer, 27 October 2021 - 11:51 PM.


#3 bobzeq25

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Posted 28 October 2021 - 02:20 AM

I want to use my exposure time more efficiently owing to limited cloud free nights.  The common practice seems to be expose L for 50%, and RGB equally for the reminder.  Given that RGB exposures only provide color information and that L is the most important for resolution, what is the minimum ratio of RGB to L?   Knowing this will  allow me to maximize the time imaging with the L filter.   Thanks in advance.

Common practice is pretty near ideal.  As is often the case.  "The wisdom of crowds" applies.

 

I suggest you read this before cutting back "too much" on the color data.  This is a very expert imager.

 

https://astroimages....good-color.html


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#4 fate187

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Posted 28 October 2021 - 04:10 AM

From my experience it is better to expose RGB the more the better, if you live in light polluted environment. Otherwise blotchiness and/or uneven background with very difficult color gradients are the result.



#5 Rasfahan

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Posted 28 October 2021 - 09:26 AM

Yes, in Bortle 4, 50%L and 50% RGB (combined) worked very well. In Bortle 6 I need better color data, so I‘ve started to expose each channel for the same time. Skipping L, I find I get „too much“ color - i. e. while saturation can be pushed a lot, stretching reveals more noise. The brighter the object, the less RGB I need, as a rule.




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