QHY268C Gain values

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cairomike
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QHY268C Gain values

#1

Post by cairomike »

Hi.

Could someone explain how the 'Gain Value' in sensor analysis corelates to the 'Gain' slider please.

In sensor analysis the Gain Value column goes from 0 to 100, or 0 to 200 depending on the mode, but the Gain slider goes from 0 to 339 in all modes, so it's a bit confusing.

Thanks
Mike
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Re: QHY268C Gain values

#2

Post by admin »

Hi,

the 'gain value' is the value of the gain slider. However... SharpCap may not analyze the full range of the gain slider.

Some cameras have a very wide gain range - I have one on my desk at the moment that has a range in excess of 3000:1. SharpCap typically does not take the analysis beyond 300 times as bright as minimum gain for two reasons

1: Beyond 300x gain, cameras tend to be so noisy as to be unusable for any deep sky work. Beyond 1000x gain they are typically too noisy for pretty much anything.

2: Analyzing a very wide gain range requires an equally wide range of exposure times, which would either require rather long exposures (>1s) leading to slow analysis or very short exposures (<1ms) which have their own issues with fine adjustment not being available on some cameras.

Essentially, near the beginning, the analysis works out how large a gain value it can go up to and still keep the analysis within reasonable bounds of exposure length. Depending on the model/mode, this might be 100, 150, 200 gain.

cheers,

Robin
cairomike
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Re: QHY268C Gain values

#3

Post by cairomike »

Thanks Robin, understood.

Mike
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