artemis 285

Simon DawesSimon Dawes

Artemis 285Artemis 285

Kit

Assembly

The Completed Camera

Problem 1Problem 1

Thermal readout noise

Solution:

1.New Peltier

2.More thermal paste on peltier (although Dark subtraction was quite effective)

Problem 2Problem 2

Dust donuts!

Solution:Flat fielding Light box(although they can sometimes be removed with clever processing)

Problem 3 & 4Problem 3 & 4

Gradient from top left to bottom rightSolution:Turn off Amp during exposure(Latest software always selects this for long exposures)

Weird patterns! – Dew on CCDSolution:Seal the cold frame, desiccant was tryingto dry the whole Earth! CCD was dripping wet

Problem 5Problem 5(will they ever stop)(will they ever stop)

Another weird pattern! - FrostSolution:Thermal paste sealing CCD window, to warm the window slightly

Flat field light boxFlat field light box

Raw 15s Frame, note top-bottom Raw 15s Frame, note top-bottom gradient and dust donutsgradient and dust donuts

Stacked, dark subtracted, cube Stacked, dark subtracted, cube route scaled, de-convolvedroute scaled, de-convolved

Notice dust donuts (poor flat field) Notice dust donuts (poor flat field) and sky gradient going from top left and sky gradient going from top left

to bottom rightto bottom right

Median rank operator removes Median rank operator removes small scale structure, leaving the small scale structure, leaving the sky gradient, donuts and Globularsky gradient, donuts and Globular

19,000 is added to every pixel in 19,000 is added to every pixel in original imageoriginal image

One Image is subtracted from the One Image is subtracted from the other, removing gradient and other, removing gradient and

donutsdonuts

Background is smoothed to remove Background is smoothed to remove some noisesome noise

Any pixel value less than 21,000 Any pixel value less than 21,000 ADU is set to 17,000ADUADU is set to 17,000ADU

Black and white levels are adjustedBlack and white levels are adjusted