Weekly Report 11Mar2011
From RHESSI Wiki
RHESSI Albedo Imaging Test
An IDL routine was written that allows a map to be created, from the map a calibrated eventlist file is made, and from the calibrated eventlist file, an image is made. For each image, the Full Width Half Max was calculated in the X and Y directions. This was compared to the FWHM of the original map.
For the case below, the FWHM of a circular Gaussian is plotted versus the FWHM in the X and Y direction for clean images.
The Red line is the FWHM in the X direction. The Green line is the FWHM in the Y direction. They are plotted versus the FWHM of the of the original image which is symmetric. The X=Y line shows the points were the FWHM of the image should be equal to the FWHM of the original map. As the original FWHM of the Gaussian map increases the image gets less reliable at reproducing it using Clean. This seems to be due to Clean using point sources convoluted with a Clean beam. When Visibility Forward Fit is used for larger original sources, the FWHM of the original maps was more accurately reproduced (within approximately ~3% in the X and Y directions for an original source of 30 arcsec FWHM). This may not work for large extended sources however, since Visibility Forward Fit starts with the assumption of a Gaussian source.
The side lobes present in the original Pixon maps were found to be a product of the detectors used. When detectors 1,2 and 3 were removed the side lobes disappeared.
RHESSI Website Migration
Some work was done on formatting of the website. I'm currently looking at Front End settings in the template and in the settings of the Rich Text Editor for the HTML area module. I am trying to change the setup so the HTML area accepts all formatting implemented on the backend.
Goals
- Change the routine that calculates the FWHM for images so that selection of contours is automated.
- Check FWHM measurements for images including extended sources, not just compact Gaussian sources.
- Make changes on the frontend display of the HTML so it displays all formatting implemented on the backend.
