Project

General

Profile

PSF-G2

Donut and BCAM data agree on DECam decentering to 200 um RMS

Prerequisites

Hexapod data written to FITS header.
F/A Donut analysis running for each frame and results written to FITS headers.
BCAMs operational and readouts written to FITS headers.

Procedure

Images are taken with a range of filters and exposure times (all taken from other SV data). Conceptually, hexapod position + F/A offsets = BCAM position. Convert translation/tilt information into translations at the upper and lower BCAM positions. Compute rms offset (radius) between the F/A and BCAM data, excluding any aberrant F/A data.

Verdict

RMS < 200 microns.

Consequences

Disagreements may indicate that either the F/A system or BCAM system or both are not performing at the expected level. Further diagnostic data would include taking large numbers of donut frames using the science CCDs to obtain a more complete picture of residual misalignments.