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AaronAndrews - 01 Dec 2016
Observation on 25/11/2016:
- Observation 2: 20161125
- Took multiple luminous, red, visual, and blue frames of Double Cluster and Dragonfly Cluster.
- Used guide scope to control star tracking. Therefore, could stack frames.
- Example: Double cluster, blue, total exposure time (for 5 frames) 200s - more stars visible:
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- Uplaoded all stacked frames to astrometry.net to fit:
- Coordinates at image centers:
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| Filter | RA | DEC |
Double Cluster | blue | 02h 22m 06.252s | +57° 11' 05.203" |
| visual | 02h 22m 05.818s | +57° 11' 11.674" |
| red | 02h 22m 05.973s | +57° 11' 10.444" |
Dragonfly Cluster | blue | 01h 19m 21.635s | +58° 21' 26.031" |
| visual | 01h 19m 29.901s | +58° 21' 01.003" |
| red | 01h 19m 26.550s | +58° 21' 11.465" |
Simulation:
Simulation_test11.py.txt
- Can generate background mean (or standard deviation) using taylor series:
- In order to get parameters, set up code to do a fit over an array of values using the expansion, up to a set number of terms.
- First applied fit directly to image of M103 from observation 1, up to 25 terms:
- LEFT: original image, M103. RIGHT: taylor series fit (25 terms, origin=(0,0))
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- Then applied median analysis to frame first, then attempted fit (25 terms):
- LEFT: Median filter for M103. RIGHT: taylor series fit (25 terms, origin=(0,0))
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- Attempted to fit up to 100 terms - failed.
Truncated Histogram:
- Aim to make a mode filter over an image by defining a function that returned the mode of a truncated histogram
- Stars populate the tail of the histogram with low frequencies --> set threshold frequency for mode filter as 1000/((1530*1020)/65^2) = 2
- The mode is the pixel value with the highest frequency
- Fit a gaussian to the truncated histogram, the mean of the gaussian corresponds to the mode of the truncated data
- If there are not enough bins (less than 25), fit may not be executed, therefore we estimate the mode by finding the bin with the maximum frequency, return single value of mode
- Run mode filter using output from truncation algorithm to obtain an array of modal pixel values
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