Hot Pixels

*The background data of a dark frame was plotted at an exposure of 2 s and a temperature of 10deg.

• Background_hot.png: • The large spikes in the plot are believed to be 'hot pixels'
• By finding the standard deviation and mean of the background data, any points that were larger than the standard deviation plus the mean were recorded. This process is repeated for 2 dark frames so that the hot pixels can be determined.
• For the 1st frame, pixel values exceeding this limit were located at pixel positions 90, 180, 222, 407, 490, 497, 617 along the x axis.
• For the second frame, pixel values exceeding this limit were located at positions 90, 222, 407, 617 along x axis.
• We can then conclude that the repeated positions are 'Hot pixels'.
• The 'hot pixels' were then set to a value of the average of its surrounding pixels. This then gave a plot of:

• Background_nohot.png: • The background can be seen to be rising in intensity towards one side of the camera. Not sure as to why?
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.
• Focus : = 0.00665
• Angle : = 0.000382
• Still need to adjust errors - will ask Prof Cowan in own time
• Focus_fit.png: • Angle_fit.png: Mapping grating micrometer position to wavelength

• Initiall two plot were made of cadmiums spectrum at 3.5 mm and 4.0 mm,
• 3.5_4.0_pixel.png: • The pixel distance between the same peak in each frame was found to be 277.
• By then finding the initial plot in nm, the pixel distance between the same peak could be subtracted to get the correct value as shown below:

• 3.5_4.0_wavelength.png: • By then applying this across the all of the frames of the spectrum, the spectrum for cadmium was obtained, however the values are not quite correct:  Home   Public Web  P P P P P View Edit        