Hot Pixels

  • Analysed a two dark frames to find locations of hot pixels. 1st Dark frame had a 1 second exposure time at a temperature of 20 degrees. 2nd Dark frame had a second exposure time at a temperature at 5 degrees.
  • As can be seen from both spectrums below, the 2nd dark frame has comparatively less background fluctuations due to the lower temperature.
  • A code was written to print the index of the pixel values which exceed the mean+standard deviation of the 1D array obtained from summing each column of pixels downwards. Pixel values exceeding this limit are considered signicantly above the background.
  • Spectrum of dark frame analysed with spikes indicating hot pixels:

3 second dark frame

  • Pixel values exceeding this limit were located at pixel positions 90, 180, 222, 407, 490, 497, 617 along the x axis for the 1st dark frame.
  • Pixel values exceeding this limit were located at positions 90, 222, 407, 617 along x axis for 2nd dark frame - conclude these are hot pixels.
Finding the best focus distance/camera angle

  • After meeting on 28/10/15, decided to fit a hyperbole to the standard deviation against focus distance plot and a sine function to the standard deviation against camera angle plot - these fits were a much better fit than the parabolas.
  • Chi square value for focus = 0.00665
  • Chi square value for angle = 0.000382
  • Still need to adjust errors - will ask Prof Cowan in own time


-- AshleaKemp - 02 Nov 2015

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng Angle.png r2 r1 manage 33.8 K 02 Nov 2015 - 11:58 AshleaKemp stdev versus angle
PNGpng Focus.png r2 r1 manage 31.9 K 02 Nov 2015 - 11:59 AshleaKemp stdev versus focus
PNGpng Hot.png r1 manage 36.0 K 02 Nov 2015 - 01:55 AshleaKemp dark frame 2s 5 deg
PNGpng Hotpixels.png r1 manage 33.5 K 02 Nov 2015 - 01:39 AshleaKemp Dark frame spectrum
PNGpng g.png r1 manage 36.7 K 02 Nov 2015 - 02:07 AshleaKemp 3 second dark frame

This topic: Public > UserList > StewartBoogert > StewartBoogertAstronomy > StewartBoogertMSciProjects > StewartBoogertSpectroscopy2015 > 20151101_MSciSpectrocopyLab
Topic revision: r2 - 02 Nov 2015 - AshleaKemp
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