Tilt in LBC Red

Analysis of extra-focal 4-chip images taken on 20111210 indicates some tilt in LBC-Red.

There are 5 extra-focal pupil images analyzed for Blue and Red: 3 with PA=0, Rotator Angle ~ 0 and 2 with PA=180, Rotator Angle ~ -180 degrees.

LBCFPIA was run on subsections of these images, but editing the LBCChip and ImgSec in the lbcfpia.cfg file (I added and uncommented these lines). There are scripts: focus.idl and focus2.idl which, for a single image, edit the cfg files and output "Median External Diameter" for each of 12 subregions of the science field (3 subregions per chip).

For Red PA=0 data, there is a clear trend toward larger diameters towards the bottom right, with a maximum of 6 pixels greater than the center. For Red PA=180 data, this is not exactly reproduced.

See the attached LBTtilt files (pdf is not formatted correctly --- have to correct).

-- OlgaKuhn - 18 Dec 2011