Read out noise

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Joined: Tue Nov 26, 2019 9:26 pm

Read out noise

Post by tp2415 »


Sharpcap was originaly for planetary but right now is used for DSO due to a lot of functionalities.
With CMOS cameras there are frequently 2 modes: video and single.
Does read out noise change between each mode?
Does Sharpcap use those modes or is not applicable?

In CCD we can choose for low rate transfert but less readout noise or high rate (like planetary).
Can we tune sharpcap to low read noise (for Hypercam 1600)? :roll:
thank you
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Re: Read out noise

Post by admin »


For CMOS cameras there is a readout circuit (ADC) on every single pixel – once the data comes off the pixel it is in purely digital format. There is no real equivalent to the adjustment of readout speed to affect noise levels that applies for CCD cameras. Instead the read noise is controlled typically by adjusting the analogue gain that is applied to the accumulated charge as it is fed into the ADC. Higher gains lead to reduced read noise along with reduced full well depth.

With respect to the difference between video and still mode, for most types of camera SharpCap auto transitions between the two as the exposure length changes. Qhy cameras are an exception to this where the transition can be made by a control available in the controls panel. Typically the camera switched into still mode as the exposure goes beyond about 1 to 2 seconds.

Cheers, Robin
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