Between july and november 2003, SOFI suffered various major operations. The last one was mainly planned to replace the wheels (two filter wheels and slit/mask wheel). During the intervention, we tried to improve the image quality of the large field mode.
Here you ca find the results...

Several images of NGC 6864 were taken in J,H,Ks and Js (a new comer!). In Ks the cluster is not bright enough to do a good image quality measurment. For J,H and Js, you can see the images, the plot of the simple analysis with SExtractor, then the plot of the ellipticity versus the axis (X and Y) and the table of the parameters of each "star" ( X, Y, A, B, Theta, elongation, ellipticity).

NB : To see two graphs in a row, enlarge your browser.

All the files available in postscript format.

PS : All the values closed to the centre of the cluster are not really usable as the density is too high to properly analyse the shape of the stars. But, as the
main optical deformations were at the corners, the images of the cluster allows us to have some stars at the corners.

Filter J

Filtr Js

Filter H