ISPI Noise & noise patterns
A simple receipe to measure the noise:
- Collect 10 darks at shortest exposure (3.227s)
- Subtract last 3-4 pairs from each other
Dark10-Dark9, Dark9-Dark8, etc
- imstat with lo=-100 hi=100, to get rid of outlayers
- Divide average std number by sqrt(2) and multiply by 4.25e-/ADU (gain)
- If number is less than 20e-rms, the noise is within specs.
- If the number is more than 20e-rms, ask moutain support to
- check that the cables and ground strap are well-tighed and perhaps ask them to move the cables.
- Switching the motors for the filterwheels OFF & ON might help too.
- Measure the noise again, and again...
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