ISPI Noise & noise patterns

A simple receipe to measure the noise:

  1. Collect 10 darks at shortest exposure (3.227s)
  2. Subtract last 3-4 pairs from each other
    Dark10-Dark9, Dark9-Dark8, etc
  3. imstat with lo=-100 hi=100, to get rid of outlayers
  4. 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.
  1. Measure the noise again, and again...


Site under construction

February 21,2007

Updated on May 28, 2021, 10:38 am