Performance Predictions for a 56x56 subap system at Palomar
This page contains some preliminary performance predictions for a
proposed upgrade of the Palomar AO system to a 56x56 subaperture
system. These simulations are the first attempt at generating high
fidelity performance predictions, and are not meant to be
representative of the final system performance. The simulations used
a sensing wavelength of 589 nm, but assumed a natural guide star. The
science wavelength was chosen to be 656 nm (H alpha). The simulation
was conducted with an update rate of 2.5 kHz, and ran for a third of a
second. A movie showing the uncorrected, corrected, and perfect point
spread functions on a log stretch. Each image is 2 arcseconds across.
Simulated PSF's
A new problem arose in these high subaperture count simulations. The
9 cm subaperture spacing is smaller than the 12 cm spiders assumed in
the simulation. Consequently, the corrections applied to the
different quadrants of the pupil tended to aquire an overall relative
piston component, leading to a degradation in coherence. The relative
piston component drifted throughout the simulation, acquiring values
of order a radian at the sensing wavelength of 589 nm. This type of
error may be addressed by using a reconstructor that incorporates
Komolgorov statistics to make better predictions across the spider
gaps.
Here is a plot of the Strehl
history.