-- 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. *

Edit | Attach | ~~Watch~~ | Print version | History: r2 < r1 | Backlinks | Raw View | Raw edit | More topic actions

Physics Webpages
•
RHUL Webpages
•
Campus Connect
•
Royal Holloway, University of London, Egham, Surrey TW20 0EX; Tel/Fax +44 (0)1784 434455/437520

Topic revision: r2 - 14 Oct 2016 - AaronAndrews

Copyright © 2008-2023 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

Ideas, requests, problems regarding RHUL Physics Department TWiki? Send feedback