ASI 1600 MM-C Sensor analysis - M 42

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SdA
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ASI 1600 MM-C Sensor analysis - M 42

Post by SdA » Sun Jan 28, 2018 3:40 pm

Hi,
this is the sensor analysis of my ASI 1600 MM-C, -15°C.
I'll try to take photos of M42 with gain 200, offset 50, 10s, 60s and 180s.
I am in the middle of a small town with moderate light pollution and good seeing (these nights).
What do you think about the gain? Gain 200 is good or i have to use another value ? for example 75 or 300 ?
Thank you.
SharpCap Sensor Analysis Lum -15.JPG
SharpCap Sensor Analysis Lum -15.JPG (122.94 KiB) Viewed 369 times

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Re: ASI 1600 MM-C Sensor analysis - M 42

Post by admin » Mon Jan 29, 2018 7:11 am

Gain 150 would be a good start - it's just above unity gain and has a low read noise compared to minimum gain.

Ideally you should use the 'Brain' feature in the Smart Histogram to calculate the optimum exposure based on your sensor measurements, gain and sky brightness. This will calculate an exposure that is at the point of diminishing returns - ie choosing longer exposures than the calculated one will not give a better final stacked image by any significant amount.

cheers,

Robin

PS. The measurements made in sensor analysis of the e/ADU and read noise are not very sensitive to temperature (cooling). The thing that does depend on cooling is the thermal noise which sensor analysis doesn't measure (because it would take a very long time to wait for cooling, take long exposures, etc). However, with most modern CMOS sensors the thermal noise is going to be lower than the sky noise unless (a) you have world class dark skies or (b) you are imaging in narrowband. That means the thermal noise can usually be ignored compared to the sky brightness.

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