-- AaronAndrews - 25 Oct 2016

To do by Friday:

• Anisha:
• Fit sqrt(sigma0^2 + lambda*t) to the fitted standard deviation as a function of exposure time plot
• Aaron:
• Simulate background.
• Generate stars in fiducial volume around frame.
• Generate full size star field (1530x1020), use uniform randomised values for all star variables (positions, fluxes, sigmas, correlation).
• Laura:
• Fix star-finding code, attempt to calculate flux for each star
Weekly Progress:

Anisha:

* Histogram of a dark frame 0.1s exposure:

• The fitted mean and fitted sigma as a function of exposure time:

• The mean as a function of exposure time is linearly fitted with nu_0 + mu*t
• Parameters obtained:
• Nu0: 917.858645977
• Mu: 0.0759400473796
• The sigma as a function of exposure time is fitted with sqrt(sigma0^2 + lambda*t)
• Parameters obtained:
• Lambda: 0.0364088264173
• Sigma0: 6.44315650804

Aaron:

• Simulation code: Simulation_test6.py.txt
• Added generation of background to simulation. Assumed background values follow gaussian distribution - Python has a random gaussian generator with mean and S.D. as inputs.
• Stars can be generated outside of image frame (up to 15 pixels from edge).
• Randomly generated star parameters can be saved in text files.

• Generated a full-size star field, making estimates for some values/ranges for a 10 second exposure, and maximum signal/background ~2.
• Properties:
• Size: 1530x1020
• Stars in frame: 50
• Background mean: 918.23
• Background S.D.: 23.06
• Random parameter ranges (uniformly distributed):
• Peak x position: [-15,1544]
• Peak y position: [-15,1034]
• Sigma_x: [3,6]
• Sigma_y: [3,6]
• Rho: [-0.5,0.5]
• Peak value: [0,2000]
• Star parameters: RandStarField1a.txt
• Alternative generation, estimating 300 second exposure, maximum s/b~60:
• Background mean: 941.43
• Background S.D.: 234.76
• Peak value range: [0,60000]
• Star Parameters: RandStarField1b.txt
Laura:
• Code: StarFinder.txt
• Program now stores all coordinates in a star, mean pixel values (count) of the star used to calculate star flux
Topic attachments
I Attachment History Action Size Date Who Comment
png FittedMeanAsAFunctionOfExposureTime.png r1 manage 36.1 K 28 Oct 2016 - 13:25 AnishaVadher Fitted mean as a function of exposure time
png HistogramForDarkFrame0.1Exposure.png r1 manage 30.8 K 28 Oct 2016 - 13:22 AnishaVadher Histogram of a dark frame 0.1s exposure
png MeanAndSigmaAsAFunctionOfExposureTime.png r1 manage 59.3 K 28 Oct 2016 - 13:39 AnishaVadher The fitted mean and fitted sigma as a function of exposure time
png RandStarField1a.png r3 r2 r1 manage 474.6 K 28 Oct 2016 - 12:34 AaronAndrews Random star field simulation, estimating 10 second exposure
txt RandStarField1a.txt r1 manage 5.4 K 27 Oct 2016 - 09:56 AaronAndrews Generated star parameters for random star field 1a
png RandStarField1b.png r3 r2 r1 manage 353.0 K 28 Oct 2016 - 12:35 AaronAndrews Random star field simulation, estimating 300 second exposure
txt RandStarField1b.txt r1 manage 5.4 K 27 Oct 2016 - 09:57 AaronAndrews Generated star parameters for random star field 1b
txt Simulation_test6.py.txt r1 manage 10.9 K 27 Oct 2016 - 09:53 AaronAndrews Simulation test 6 code
txt StarFinder.txt r1 manage 2.9 K 28 Oct 2016 - 11:49 LauraBevilacqua Star finding code

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

Topic revision: r6 - 28 Oct 2016 - AnishaVadher

 Home Public Web P P P P P View Edit Account
Copyright © 2008-2024 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