# Difference: StewartBoogertPhotometry20161013Analysis (1 vs. 2)

#### Revision 214 Oct 2016 - AnishaVadher

Line: 1 to 1

 META TOPICPARENT name="StewartBoogertPhotometry2016"
-- AnishaVadher - 13 Oct 2016

• Working out how much background for each pixel
• Plotted a histogram of number of photoelectrons against the frequency for a 0.1s exposure in the dark frame which follows a Gaussian distribution
>
>

• Number of photoelectrons = pixel value (ADU) * Gain
• Gain = 2.3 e/ADU (value from PH2900 report)
• From the histogram I will obtain the value at the peak and the error from the FWHM
• Error in the peak = FWHM/2.35
• I will get these statistics for each exposure time in the dark frames that I have taken and plot the peak value as a function of exposure time and the error as a function of exposure time.
• There are big gaps between the bins which I am not sure why.
>
>
• Edit - the gaps are due to the fact that the histogram only takes integer values so increasing the number of bins leads to more gaps in the histogram.
• Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 45 bins.:

• Also plotted a histogram for the sum of pixel along the x-axis values against frequency for a 0.1s exposure in the dark frame which follows a Poisson distribution
• The histograms from the sum of pixels along the y-axis follows a Gaussian distribution.
>
>

• Plotted the median intensity of the pixels as a function of exposure time using the values given from the image using np.median in python. I am yet to work out the errors.

• The median intensity as a function of exposure time.:

 META FILEATTACHMENT attachment="Histogram_of_number_of_photoelectrons_for_0.1s_exposure.png" attr="" comment="Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame." date="1476399535" name="Histogram_of_number_of_photoelectrons_for_0.1s_exposure.png" path="Histogram of number of photoelectrons for 0.1s exposure.png" size="18803" user="zyva858" version="1" attachment="Difference_between_summing_across_x-axis_and_y-axis.png" attr="" comment="Histograms to show the difference between summing across x-axis and y-axis for 0.1s exposure dark frame" date="1476399674" name="Difference_between_summing_across_x-axis_and_y-axis.png" path="Difference between summing across x-axis and y-axis.png" size="39734" user="zyva858" version="1"
>
>
 META FILEATTACHMENT attachment="Histogram_of_number_of_photoelectrons_for_0.1s_exposure_45_bins.png" attr="" comment="Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 45 bins." date="1476442640" name="Histogram_of_number_of_photoelectrons_for_0.1s_exposure_45_bins.png" path="Histogram_of_number_of_photoelectrons_for_0.1s_exposure_45_bins.png" size="19103" user="zyva858" version="1" attachment="The_median_intensity_as_a_function_of_exposure_time.png" attr="" comment="The median intensity as a function of exposure time." date="1476443160" name="The_median_intensity_as_a_function_of_exposure_time.png" path="The_median_intensity_as_a_function_of_exposure_time.png" size="33910" user="zyva858" version="1"

#### Revision 114 Oct 2016 - AnishaVadher

Line: 1 to 1
>
>
 META TOPICPARENT name="StewartBoogertPhotometry2016"
-- AnishaVadher - 13 Oct 2016

• Working out how much background for each pixel
• Plotted a histogram of number of photoelectrons against the frequency for a 0.1s exposure in the dark frame which follows a Gaussian distribution
• Number of photoelectrons = pixel value (ADU) * Gain
• Gain = 2.3 e/ADU (value from PH2900 report)
• From the histogram I will obtain the value at the peak and the error from the FWHM
• Error in the peak = FWHM/2.35
• I will get these statistics for each exposure time in the dark frames that I have taken and plot the peak value as a function of exposure time and the error as a function of exposure time.
• There are big gaps between the bins which I am not sure why.

• Also plotted a histogram for the sum of pixel along the x-axis values against frequency for a 0.1s exposure in the dark frame which follows a Poisson distribution
• The histograms from the sum of pixels along the y-axis follows a Gaussian distribution.

 META FILEATTACHMENT attachment="Histogram_of_number_of_photoelectrons_for_0.1s_exposure.png" attr="" comment="Histrogram of number of photoelectrons for a 0.1s exposure in the dark frame." date="1476399535" name="Histogram_of_number_of_photoelectrons_for_0.1s_exposure.png" path="Histogram of number of photoelectrons for 0.1s exposure.png" size="18803" user="zyva858" version="1" attachment="Difference_between_summing_across_x-axis_and_y-axis.png" attr="" comment="Histograms to show the difference between summing across x-axis and y-axis for 0.1s exposure dark frame" date="1476399674" name="Difference_between_summing_across_x-axis_and_y-axis.png" path="Difference between summing across x-axis and y-axis.png" size="39734" user="zyva858" version="1"

Copyright © 2008-2022 by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding RHUL Physics Department TWiki? Send feedback