PSF (Point Spread Function)

The Point Spread Function subsystem is responsible for adjusting the position of all three optics and the primary mirror figure to obtain the best possible image based on operator input, elevation angle, temperature, and Zernike polynomial coefficients sent from the Offaxis wavefront system and instruments. Tilt, coma, and focus are compensated for by moving the primary and/or the secondary mirror in the appropriate way. Other distortions are compensated for by adjusting the forces on the mirror support actuators; the needed force corrections are calculated from the bending modes of the primary mirror. Elevation angle and temperature are used to calculate static corrections based on 3rd order polynomials. for both position and figure corrections. An operator interface (GUI) is provided that allows the operator control of all functions.

digraph G { rankdir=LR node[style=filled, shape=box] subgraph cluster_tcs { style=invis node[fillcolor=gray] TCS GCS }

PSF[fillcolor=lightblue]

subgraph cluster_sub { style=invis node[fillcolor=gold] PMC OSS }

TCS->PSF GCS->PSF PSF->PMC PSF->OSS }

PSF documentation includes

• T481s00062 PSF Subsystem User's Manual
• Basic PSF notes on the commissioning wiki