# Difference: StewartBoogertPhotometry20161021 (8 vs. 9)

#### Revision 921 Oct 2016 - AnishaVadher

Line: 1 to 1

 META TOPICPARENT name="StewartBoogertPhotometry2016"
-- LauraBevilacqua - 18 Oct 2016
Line: 19 to 19
Anisha:
Changed:
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• Corrected histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 500 bins - logarithmicly normalized:
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• Corrected histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 500 bins - logarithmicly normalized:

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

• Line of best fit: y = 917.43 + 0.08x
Changed:
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• Error as a function of exposure time:
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• Error as a function of exposure time:

• Line of best fit: y = 15.76 + 0.73x
%BEGINLATEX% Mean number of effective photoelectrons : $$\nu = \nu_0 + \mu t.$$ Actual number of photoelectrons: $$n = n_0 + m,$$ where $n_0$ follows a Gaussian distribution and may come from electronic noise and $m$ follows a Poisson distribution as a function of $\mu t$. Error in $m \sigma_m$ come from $\sqrt{\mu t}$.
Line: 60 to 60

• Images scanned for stars and correct star count is returned
• Edge detection helps identify star position
Changed:
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• The maximum pixel value was found to be 65195 from the fits file below, as opposed to Aaron's given value of 65535
• Threshold of 100 set so if pixels are above this value they are set as white background, if below they are coloured black (remember reverse grayscale):
• Edge detection:
>
>
• The maximum pixel value was found to be 65195 from the fits file below, as opposed to Aaron's given value of 65535
• Threshold of 100 set so if pixels are above this value they are set as white background, if below they are coloured black (remember reverse grayscale):
• Edge detection:

Changed:
<
<
• Maximum pixel value found to be 62673, compared to Aaron's 60000:
• Threshold set as 20 so that stars don't touch, achieves accurate count of 8:

>
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• Maximum pixel value found to be 62673, compared to Aaron's 60000:
• Threshold set as 20 so that stars don't touch, achieves accurate count of 8:

 META FILEATTACHMENT attachment="SkewTest2.png" attr="" comment="Testing x and y correlation (P) for P=0, P=0.5, P=0.999" date="1476827216" name="SkewTest2.png" path="SkewTest2.png" size="19013" user="zyva010" version="1" attachment="Histogram_of_number_of_pixel_values_for_0.1s_exposure_500_bins.png" attr="" comment="Corrected histrogram of number of photoelectrons for a 0.1s exposure in the dark frame with 500 bins - logarithmicly normalized" date="1476982418" name="Histogram_of_number_of_pixel_values_for_0.1s_exposure_500_bins.png" path="Histogram_of_number_of_pixel_values_for_0.1s_exposure_500_bins.png" size="18847" user="zyva858" version="1"

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