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M31 blown out

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#1 AndyRN

AndyRN

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Posted 23 October 2021 - 09:23 AM

Question: The center seems saturated at my current settings without any stretching.  Should I decrease gain or decrease exposure time?  I'm leaning toward lowering gain but looking for thoughts.  There is no room for me to do any sort of initial stretch to really get to the point where I can mask the center of the galaxy to continue the stretch.  These settings have been fine so far for nebulae but not working for this.  

 

Evostar 72ED with FLO flattener

Canon 600D/T3i Modified

 

90sec exposures at 800 gain.



#2 Midnight Dan

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Posted 23 October 2021 - 09:39 AM

M31 has a huge dynamic range.  The core is extremely bright and the outer fringes extremely dim.  If you're having trouble capturing it all correctly, you can take two sets of images.  One can be very short exposures of 15 to 30 seconds, to correctly expose the core, and the other set can be longer exposures to correctly expose the outer areas.

 

Process each set separately, then blend the two together.

 

But I think 800 ISO is about right for that camera.  So I'd play with exposure lengths.

 

-Dan


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#3 AndyRN

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Posted 23 October 2021 - 10:06 AM

M31 has a huge dynamic range.  The core is extremely bright and the outer fringes extremely dim.  If you're having trouble capturing it all correctly, you can take two sets of images.  One can be very short exposures of 15 to 30 seconds, to correctly expose the core, and the other set can be longer exposures to correctly expose the outer areas.

 

Process each set separately, then blend the two together.

 

But I think 800 ISO is about right for that camera.  So I'd play with exposure lengths.

 

-Dan

Thanks Dan, you are correct 800 or 1600 is the right ISO for this camera; in my mind I think 800 is better because it's modified.   I don't think this camera has great dynamic range.  I will try the blending next time.




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