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THIS PAGE IS NO LONGER MAINTAINED - See relevant sections in the New Operating Procedures.
At the start of the night, align the red and blue beacons following the “Beacon Alignments” section in the Operating Procedures. These alignments should be done with the telescope at stow with M7 in the default position. During this process, use the Dichroic to align the blue beacon to the labAO WFS. Because we are no longer sending M7 to the default position during the slew sequence, this is the only time that we should adjust the dichroic.
IMPORTANT NOTE: For the beacon/dichroic alignment at the beginning of the night, the red beacon must be aligned to the default starlight boxes. You can either zero out any offsets between the beacon (green) boxes and the starlight boxes on the telescope WFS (using ZERO BCN) or use the starlight (blue) boxes to align the red beacon during this step.
If the green beacon box position are retained from night to night, use the blue starlight boxes instead to see the IR flux misalignment on the STST camera or use the green beacon boxes to minimize the misalignment with repeated targets.
At the start of the night align the red and blue beacons at stow using these steps:
Checks to make sure beacons are aligned properly to TWFS:
Aberration plots: The engineering versions of the wfsgtk and labaogtk are open on the wolverine2 screens. Click reopen to activate the aberration plots at the start of the night. Use these guis to ZERO CENT during the start up procedure and to montior the aberration terms during the night.
For the visible combiners the red beacon and starlight will be coaligned, so you only need to use the starlight boxes on the telescope WFS.
To avoid any confusion, at the start of the night, clear any offset between the position of the beacon boxes and the starlight boxes on the telescope WFS using the “ZERO BCN” button on obsgtk.
The path of the IR light will be different from the visible light because of dispersion in the AO dichroic and atmospheric refraction. To compensate for this offset, we have two sets of boxes on the telescope WFS. The blue boxes are for starlight and the green boxes are for aligning the red beacon. The offset between these sets of boxes will change depending on the azimuth and elevation of the target.
The green beacon boxes help keep track of the beacon motion. These are defined as an offset to the starlight position, so if you move the starlight boxes, the beacon boxes will also move. If you move the beacon boxes only they will move.
We will use the Six Telescope Star Tracker (STST) to align the IR starlight in the lab.
Before the start of the night, use the Six Telescope Simulator (STS) to set the reference boxes on the Six Telecope Star Tracker (STST). Here are brief instructions:
If the STST camera is already running, you can open a second GUI by typing “ststrtd_gtk” in a terminal and click the “Start RTD” button to start the display. You can adjust the contrast of the display by changing the number in “Flux” box in the upper right of the GUI.
The STST centroiding servo now works for long exposures. If you change exposure time or coadds, you need to stop the camera, config the camera, restart the camera, and retake backgrounds. Try changing coadds to 5 or 10 for 1 sec integration to reach H=6 mag. Centroiding has been shown to work for H=8 mag using 50 sec exposure (1 coadd). Please inform chara_engineering list if you determine settings that work good for the using the auto STST alignments at different magnitudes.
Before the start of the night clear any offset between the position of the beacon boxes and the starlight boxes on the telescope WFS using the “ZERO BCN” button on obsgtk. This procedure is for the first slew and uses the standard alignment to see the IR flux misalignment on STST. Subsequent slews will use fewer steps.
When slewing to the subsequent stars, align the red beacon using the new positions for the green beacon boxes (not the blue starlight boxes), then switch to the starlight boxes when locking starlight. If the slew is close on the sky, you might not have to re-align the beacon flat to STST (skip steps 9-15 above if star is already well aligned on STST).
Faint stars (H > 5 mag) will not be easily visible in STST. Slew to a nearby bright star to align the beacon flat and set the beacon box offsets on the TWFS. Then slew to faint star and skip steps 9-15 above. NOTE: The STST centroiding now works for longer exposure times. See note in STST section above about how to change exposure time and coadds.
Programs with bright IR stars may not need any red beacon alignments when slewing and can just use the M7 and labao focus alignments. Lock the star on the blue boxes and use the STST to fine tune any misalignment of the beacon flat.
If you need to realign the lab dichroic or the IR mirror on the beam sampler stage during the night, make sure to remove STST stage (using the shutter gtk) before doing any alignments. Put STST back in the path after you are finished with the lab alignments and are ready to go on back on sky.
STST gets the beam information from the telemetry server. Try clicking RECONNECT button on ststrtd_gtk. Also try resending the updated configuration from Cosmic Debris and the OPLE GTK (yes try both!). If that doesn't work try restarting the telemetry server by typing the following into ctrscrut:
Reopen Cosmic Debris and resend configuration again. If that doesn't work then try killing and restarting mircx_stst_server on spooler@stst and running mircx_bootLaunch_master with N option (don't restart all servers - it will mess up mircx/mystic observer).
When you are finished using STST, click the “Start Camera” button to turn off the camera (the button will go from green to gray). Then change the filter wheel to the closed position. Using the shutter gtk, remove the STST stage from the beams. Reopen if needed to get stage to show it is moving out. For now, the daytime alignment is done without STST in the path so it is important to remove STST at the end of the night.
If AO performance is bad try these steps in the following order: