-- AnishaVadher - 14 Oct 2016

Anisha:

- 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.:

- Star field simulation notes - part two discussed. Note: from now on, weekly work will be presented in these 'meeting' pages.
- Discussion of work so far (i.e what needs to be changed/reviewed):
- Alternative to using numerical integration - use cumulative distribution function, find values for both limits, then use difference. Will most likely be faster method.
- 2D gaussian function not completely correct - x and y components are correlated.

- What to work on next:
- Output simulated star field data to FITS file - same file format as what is produced by camera.
- Simulate a background based on Anisha's analysis - scale to signal correctly, take exposure time into account.
- Create example starfield for Laura, with set positions etc., in order to test star finding program. *

This topic: Public > StewartBoogertPhotometry20161014

Topic revision: r2 - 14 Oct 2016 - AaronAndrews

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