Topic/Presenter: Focal Plane Array / Jon Morse

Question/Comment: 

What is the impact to choice of pixel/arcsec if PSF improves from ~0.8
arcsec to 0.5 arcsec on average, and sometimes as good as 0.3 to 0.4
arcsec.


Submitted by: Bruce Gillespie


NIC-FPS Response:


The image scale at the FPA is 0.27 arcsec/pixel (18 micron pixel size
for the H-1RG). The optical design supports good image quality with 2
pixel sampling over essentially the entire FOV. Optical and NIR seeing
statistics from APO suggest a median seeing of about 0.8 arcsec FWHM,
with occasional performance as good as 0.5 arcsec. For seeing
conditions of 0.5 arcsec or worse, the instrument should not drive the
imaging performance.

If the NIR seeing improves substantially --- for example, if a tip-tilt
capability were implemented on the secondary --- so that 0.3-0.4 arcsec
seeing conditions were common, we recommend upgrading NIC-FPS with a
new set of camera optics and a 2kx2k chip (Hawaii-2RG). We have already
modeled the imaging performance of this upgrade *within the available
space on the NIC-FPS optical bench* and find that an H-2RG option with
about 0.15 arcsec/pixel would increase the FOV slightly and provide
good image quality with 2 pixel sampling. An H-2RG would cost about
$350k, but we should be able to operate it with our existing "NGST"
packaging and drive electronics. (The package is modularly designed so
that we would literally just plug the H-2RG into the socket.) The new
camera optics would probably cost between $50-70k.


Status: Closed.