At stow:

• M7 to default
• Make sure red beacon goes into the ACQ hole, fine tune into boxes —move beacon flat
• Make sure that the laser from the lab, with m2 corner cube goes into the hole —move dichroic
• Turn off laser and red beacon and turn on blue beacon, to fine tune spots into labao —move dichroic
• Focus blue beacon on labao — then focus red beacon on telescope
• Repeat until convergence and small errors.

Slewing to star:

• At star, the red beacon on telwfs likely won't have moved much, blue beacon on labao may need significant adjustment.
• M7 to default
• Red beacon - TelWFS - beacon flat
• Blue beacon - Labao - dichroic
• Blue beacon focus - Labao - “focus beacon button” - lab parabola
• Red beacon focus -TelWFS - “focus WFS ” button scope parabola.
• Turn off red beacon.
• Lock star - TT
• Close TELWFS DM loop
• Close LABAO DM loop
• AUTOM7 - to offload tilt in lab to M7
• Star acquired
• When slewing to next star, send M7 to default position and repeat.

Implemented January-July 2023

At stow:

• M7 to default. Load default boxes on tel WFS. Load default flats on telAO and labAO.
• Move Beacon flat to center beacon in ACQ hole.
• Align TelWFS boxes to center on the red beacon.
• Align blue beacon to labAO using dichroic.
• Focus blue beacon on labAO and red becaon on TelWFS.
• If aberration terms are high, ZERO CENTROIDS to adjust relative positions of the boxes.

Slewing to Star:

• On first slew only, align red beacon to TelWFS boxes using beacon flat.
• Align blue beacon to lab WFS using M7.
• Focus blue beacon on labAO and red becaon on TelWFS.
• Turn off red beacon.
• Turn off blue beacon and lock star (TT only) - move TelWFS boxes to get star centered and evenly illuminated on ACQ hole.
• Lock star on Tel AO - DM servo
• Turn on blue beacon - lock LABAO servo
• Turn on DM AUTO - use DM to correct tilt and offload to M7 when needed.
• If coma and astigmatism high, create sky flat on bright star - Turn off [DM], [SV FLT], [FLATEN], then relock the [DM].
• For IR combiners, move beacon flat to align star to STST.
• For SPICA, move beacon flat to align star on SPICA FTT.
• Star Acquired.
• When slewing to the next star, DO NOT send M7 to default. If next star is bright, then align beacon flat to center star on STST/SPICA FTT. If star is faint, keep beacon flat fixed or align beacon flat to center red beacon in offset beacon boxes on TelWFS.

There is some controversy on whether moving the TelWFS boxes corrupts the reconstructor. During engineering time we should try keeping the boxes fixed at their reference positions when the last reconstructor was made using the CalSource. For these tests, do not move the boxes to center on the red beacon at stow, also do not use Zero Centroids to change the relative positions of the boxes. This might mean that beacon/star will be offset in the ACQ hole. It might be better to use the boxes as the absolute reference rather than the Acq hole.

In February, Norm found that some telescopes performed OK with not moving the boxes and other telescopes could not lock stars without adjusting the boxes. If the WFS boxes need to be moved, then it would be a good idea to create a new on-sky reconstructor and flat using a bright star. The gain should be high enough to give good SNR (without saturating) on the TelWFS when recording on-sky reconstructors.

Action Item: Determine best gain settings for creating on sky reconstructors. Give guidance so operators can determine whether WFS counts are approaching saturation.

Proposed Changes to the Alignment Sequence - rough ideas - comment in different color to provide feedback or propose different steps.

• At the start of a calibration sequence (first slew/pop change/new position on sky), go to a bright star.
• Send M7 to default.
• Align red beacon to the reference TelWFS boxes (NOT the offset boxes) using beacon flat.
• Align blue beacon to lab WFS using DICHROIC.
• Lock star on TT and TelAO DM.
• Move beacon flat to center star on STST or SPICA FTT.
• Measure, compute, and apply on-sky reconstructor.
• If the next star is bright enough for STST alignment, then send M7 to default and repeat sequence above. [Maybe we only have to do this if next star is far away on sky - new pops, new calibration sequence.]
• If the next star is too faint for STST [or close on sky?], then keep M7 fixed at current position and use current method of aligning blue beacon by moving M7 (instead of dichroic).

The coordinated Beacon/M7 movements (using STST button on obsgtk) will speed up compensating for big shifts after sending M7 to default.

Please do not experiment with the alignment sequence during science programs, unless the PI requests for the operator to try a new/different approach (that can be done safely) to improve performance.

From Notes from Discussion between Julien and Theo:

A shift moves the star into the hole and the detector, while a tilt with star still centered in hole will dim the stars in some external boxes and make stars appear outside of the boxes used, on the opposite side.

About star going out from Acq hole:

1-After alignment, the center of the Acq Hole matches the center of the boxes.

2-Acq Hole plane and detector plane are optically conjugated, means that what happens in Acq Hole is imaged on detector.

3-We have 3 blocks: Acq Hole + Acq camera, Collimator, and WFS (Lenslet + detector).

4-If Acq Hole translates, condition 1 is lost. If it tilts we don't care.

5-If Collimator translates, condition 1 is lost, and illumination of the sub-pupils will change. If it tilts we don't care.

6-If WFS translates, condition 1 is kept, and illumination of the sub-pupils will change. If it tilts condition 1 is lost.

I see no way to explain that star goes away from Acq Hole center while staying at boxes centers and not involving one of those 3 blocks. Whatever happens before Acq Hole in terms of tilt or shear, if the star is centered in boxes and not in Acq (or the opposite) means the initial matching between Acq Hole and Boxes is lost.