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META TOPICPARENT |
name="StewartBoogertPhotometry2015" |
Improvements
- Following on from last weeks meeting, it was suggested the colourmaps used were not overly clear.
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- A version with better contrast has been chosen, and an example is seen below, with the old version, for comparison purposes

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- A version with better contrast has been chosen, and an example is seen below, with the old version, for comparison purposes

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| Accounting for Dark Frames
- In order to accurately analyse the stars, the background caused by the camera needs to be removed.
- To do this, a dark frame was scaled down and taken away from the image seen above.
- An improved image can be seen below, with much of the noisy background regions reduced considerably.
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New algorithm for finding stars
- Used algorithm as showed here
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- We impleted some arbitrary threshold.
- We set signal to 1 and background to 0.
- We impleted the algorithm and unfortunately it has a similar problem to the previous algorithm.
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- It thinks that points not touching diagonally are stars.
- At the threshold of 1000 photoelectrons we have the following:
- We implented a crude to find the centers of each star. We only need it as an initial parameter that we will feed to our Gaussian to estimate a much better center position.
- We found the centers in the following way:
- We had the x and y coordinates of all the pixels of each star.
- We summed all x and all y for each star and then divided the sums by the amount of x and y coordinates we had.
- This we used as our centers.
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| -- DavidHadden - 24 Nov 2015
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