Beginning of Night Procedure
Note: You may want to repeat this procedure with 8x mode if looking at fainter guide stars, skipping the telescope focus and Fold1X and Y mirror adjustments.
- Put Lenslet at 16x in saomot_gui.
- Initialize 16xLGS mode: init(16)
- Make sure woofer and tweeter on, if not already on:
woof('on');mems('on')
- Set to NGS mode: ngs()
- Turn on offloading: offload('on')
- Load appropriate refcent file: refcent('data/hs-2014-08-17-BINQUAD_16xLGS_onSky.fits')
If you have a good measurement of seeing, you should make an appropriate onSky refcent file by using gavel@real:genSkyRefcents refcentfile seeing
Performance is improved by taking into account the seeing.
- Move to bright (8th mag) star near zenith.
- Focus star on guide camera.
- Send light to SAO (diagonal mirror position 3).
- Move telescope 30 arcsec N (or some other direction to get sky).
- Take WFS camera dark: dark()
- Take TT camera dark if TT Dichroic is Splitter: ttdark()
- Move telescope 30 arcsec S (or undo previous move).
- Close loops: gain(.3)
- Adjust telescope focus until foc reading in peeko is close to zero or
the value when loops are closed on the internal source.
- Adjust Fold1X and Fold1Y mirror to fine tune centering, making sure lr and ud in the peeko display are close to zero. Typical move is 500 encoder counts, though you may want to do moves as small at 200 for fine tuning.
- Increase gain until happy with performance, taking images on ShARCS to evaluate Strehl. Note, max gain in 8x mode should be around 0.3. 16x mode may take gains up to 0.7.
- Open loop: open()
- Move to science target.