Difference: StewartBoogertPhotometry20161007 (1 vs. 4)

Revision 409 Oct 2016 - AaronAndrews

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META TOPICPARENT name="StewartBoogertPhotometry2016"
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Data taking 20161004 : Exposure time scan at 5 degrees
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Meeting 20161007

 
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Anisha

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People present: Stewart Boogert, Glen Cowan, Aaron Andrews, Anisha Vadher, James Angthopo, Will Burrows
 
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Anisha:
 
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Aaron - Star Field Simulation

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'Basic' simulation program (04/10/2016): Simulation_test1.py.txt
  • Simulation generates stars with random positions.
  • Canvas size and no. of stars are variable.
  • No gaussian profile for stars or grey values (pixel value is either 0 or 1).
  • Example output: (100x100 pixel canvas, 50 stars)
  • PositionSimTest2.png
Improvement - Gaussian star profiles (05/10/2016): Simulation_test2.py.txt
  • Generated stars now have 2d gaussian profiles.
  • Maximum grey values (gaussian peak values) are randomized - can result in star not appearing in output.
  • Example output: (100x100 pixel canvas, 0-100 grey value range, 10 stars)
  • GaussianSimTest1.png
  • Example 2: (1530x1020 pixels, 0-65535 grey value range, 50 stars) (Same size of images taken by telescope system)
  • GaussianSimTest2.png
  • Running Python Programs/Functions:
    1. Change working directory
    2. 'import [filename]' (without '.py')
    3. '[filename][functionname](variables)'
  • If file is already imported, replace 'import' with 'reload' to load any changes.
  • To show an image produced by a function:
    1. 'a=[filename][functionname](variables)'
    2. 'imshow(a, cmap='Grey_r)' (use 'imshow(a)' for colourmap image instead of greyscale image)

  • Next Tasks:
    • Integration over each pixel, instead of taking central value.
    • Assume each pixel is a poisson variable - for any calculated pixel value, get random poisson distributed value (e.g. calculated pixel value is 17.5, use as mean for poisson distribution).

Laura

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Aaron:
 
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  • Current task: Star field simulation.
  • End goal of task is to generate image that is similar to what would be seen via the telescope.
  • Currently have program capable of generating an image as an array of pixels and filling flux values calculated in relation to stars:
    • Image size (no. of pixels in X and Y axis) and number of stars generated are variable.
    • Stars generated with 2d gaussian profile - each pixel filled with sum of intensity contribution from each star.
    • X and Y coordinates and peak value for each star is randomised, sigma values (in gaussian) set to 3 pixels for all stars - Eventually these will all come from simulation input data.
  • Suggestions:
    • Currently pixel value is calculated in relation to central position of each pixel - should be integral over pixel area.
    • Pixel values represent photon counts, hence follow Poisson distribution. Therefore, generate pixel value by using integrated value as mean.
(Laura - not present)

Joint task:

  • Decide on obsevation target:
    • Stellar cluster.
    • Needs to be visible at night for next few months.
    • Also needs to be visible at reasonable time of evening/night (e.g. max. altitude between 7pm and 10pm)


  -- StewartBoogert - 07 Oct 2016

Revision 307 Oct 2016 - AaronAndrews

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META TOPICPARENT name="StewartBoogertPhotometry2016"
Data taking 20161004 : Exposure time scan at 5 degrees
Line: 32 to 32
 
    1. 'a=[filename][functionname](variables)'
    2. 'imshow(a, cmap='Grey_r)' (use 'imshow(a)' for colourmap image instead of greyscale image)
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---+++ Laura
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  • Next Tasks:
    • Integration over each pixel, instead of taking central value.
    • Assume each pixel is a poisson variable - for any calculated pixel value, get random poisson distributed value (e.g. calculated pixel value is 17.5, use as mean for poisson distribution).

Laura

 

Revision 207 Oct 2016 - AaronAndrews

Line: 1 to 1
 
META TOPICPARENT name="StewartBoogertPhotometry2016"
Data taking 20161004 : Exposure time scan at 5 degrees
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  • Anisha
  • Aaron
  • Laura
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Anisha


Aaron - Star Field Simulation

'Basic' simulation program (04/10/2016): Simulation_test1.py.txt

  • Simulation generates stars with random positions.
  • Canvas size and no. of stars are variable.
  • No gaussian profile for stars or grey values (pixel value is either 0 or 1).
  • Example output: (100x100 pixel canvas, 50 stars)
  • PositionSimTest2.png
Improvement - Gaussian star profiles (05/10/2016): Simulation_test2.py.txt
  • Generated stars now have 2d gaussian profiles.
  • Maximum grey values (gaussian peak values) are randomized - can result in star not appearing in output.
  • Example output: (100x100 pixel canvas, 0-100 grey value range, 10 stars)
  • GaussianSimTest1.png
  • Example 2: (1530x1020 pixels, 0-65535 grey value range, 50 stars) (Same size of images taken by telescope system)
  • GaussianSimTest2.png
  • Running Python Programs/Functions:
    1. Change working directory
    2. 'import [filename]' (without '.py')
    3. '[filename][functionname](variables)'
  • If file is already imported, replace 'import' with 'reload' to load any changes.
  • To show an image produced by a function:
    1. 'a=[filename][functionname](variables)'
    2. 'imshow(a, cmap='Grey_r)' (use 'imshow(a)' for colourmap image instead of greyscale image)

---+++ Laura


 -- StewartBoogert - 07 Oct 2016
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META FILEATTACHMENT attachment="PositionSimTest2.png" attr="" comment="Star field sim - random positions" date="1475853090" name="PositionSimTest2.png" path="PositionSimTest2.png" size="19417" user="zyva010" version="1"
META FILEATTACHMENT attachment="GaussianSimTest1.png" attr="" comment="Star field sim - random positions+Gaussians" date="1475853122" name="GaussianSimTest1.png" path="GaussianSimTest1.png" size="27953" user="zyva010" version="1"
META FILEATTACHMENT attachment="GaussianSimTest2.png" attr="" comment="Star field sim - random positions+Gaussians (large frame)" date="1475853136" name="GaussianSimTest2.png" path="GaussianSimTest2.png" size="39743" user="zyva010" version="1"
META FILEATTACHMENT attachment="Simulation_test1.py.txt" attr="" comment="Simulation test program 1" date="1475853161" name="Simulation_test1.py.txt" path="Simulation_test1.py" size="1507" user="zyva010" version="1"
META FILEATTACHMENT attachment="Simulation_test2.py.txt" attr="" comment="Simulation test program 2" date="1475853171" name="Simulation_test2.py.txt" path="Simulation_test2.py" size="2440" user="zyva010" version="1"

Revision 107 Oct 2016 - StewartBoogert

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META TOPICPARENT name="StewartBoogertPhotometry2016"
Data taking 20161004 : Exposure time scan at 5 degrees

  • Anisha
  • Aaron
  • Laura
-- StewartBoogert - 07 Oct 2016
 
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