Observation 1

We took two images of the double cluster: NGC869, NGC884, with two different cameras, with different fields of view.

NarrowFieldView_4s_dc869.png widefield_15s_dc869.png

Star Simulation

Main aim this week: background fluctuations

From the larger image, you can see that there is a fluctuation in the background biased towards the left of the image.
Image below is the larger image with a high contrast:

BgBiasExample.png

To account for this bias, the image was analysed row by row. Taking a random row of the image and plotting the value with the column number, you get:

Fitting_Background_to_use_for_simulation.png

The majority of this is background, the spikes are stars. Then, I fit a 2d polynomial to the data. This was repeated for every row, and the parameters for the fit were averaged. This gave me the following function:

Average_background_of_Image_left_to_right_-_use_for_simulation.png

This was then used to add background fluctuations to images, poisson fluctuations also implemented.

TestbgLarge.png

A row of the above image gives the following

Background_of_Simulated_image.png

-- BekiChafer - 09 Nov 2017

Topic attachments
I Attachment History Action Size Date Who Comment
PNGpng Average_background_of_Image_left_to_right_-_use_for_simulation.png r1 manage 29.1 K 09 Nov 2017 - 22:33 RebekahChafer1  
PNGpng Background_of_Simulated_image.png r1 manage 32.9 K 09 Nov 2017 - 22:42 RebekahChafer1  
PNGpng BgBiasExample.png r1 manage 7016.1 K 09 Nov 2017 - 22:25 RebekahChafer1 High Contrast Image to show bg bias
PNGpng Fitting_Background_to_use_for_simulation.png r1 manage 39.3 K 09 Nov 2017 - 22:30 RebekahChafer1  
PNGpng NarrowFieldView_4s_dc869.png r1 manage 448.6 K 09 Nov 2017 - 14:01 RebekahChafer1 Narrow Field Image
PNGpng TestbgLarge.png r1 manage 9891.5 K 09 Nov 2017 - 22:36 RebekahChafer1  
PNGpng widefield_15s_dc869.png r1 manage 13704.4 K 09 Nov 2017 - 14:02 RebekahChafer1 Wide Field Image
Edit | Attach | Watch | Print version | History: r3 < r2 < r1 | Backlinks | Raw View | Raw edit | More topic actions...

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

Topic revision: r2 - 09 Nov 2017 - RebekahChafer1

 
  • Edit
  • Attach
This site is powered by the TWiki collaboration platform Powered by PerlCopyright © 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