New Alignment Sequences

THIS PAGE IS NO LONGER MAINTAINED - See relevant sections in the New Operating Procedures.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:

1. Send M7 to default. The End Night sequence usually does this, but it is good to confirm this.
2. Load default boxes on tel WFS (DEFBX on obsgtk). This may not allow for full beacon illumination on the TWFS. See below.
3. Load default flat on labao (LD DEF on obsgtk). Default is loaded with every server restart.
4. Load default flat on tel WFS (LD DEF on obsgtk).
5. Use blue starlight boxes to align beacon or zero beacon offset for the green beacon boxes (ZERO button on obsgtk)
6. Align red beacon to telescope WFS using the beacon flat. The alignment cheat sheet can give you directions to go to get the beacon.
7. Align blue beacon on labao using dichroic.
8. Focus beacons (first blue on labao, then red on twfs).
9. Recenter red/blue beacons again.
10. Check higher order terms - look at “TOG ABER” plots (on WFS/TT tab for wfsgtk, on ALIGN tab for labao).
11. If the astigmatism and coma terms reported by the telescope WFS are high, update the relative box positions for the red beacon using the ZCEN button on obsgtk to zero out higher order terms. (ZERO CENT moves both the beacon and the starlight boxes. The difference between those two is an X/Y offset.)(Or use ZERO_CENT button on telescope wfsgtk -E for engineering version.)
12. If aberration terms are high on labao, try making a new flat on labao using the blue beacon. (Note that the terms on labao might not go to zero because of the uneven illumination of the beacon.)

Checks to make sure beacons are aligned properly to TWFS:

• The beacon may need to be centered in the ACQ hole to fully illuminate the TWFS. Do not use the Default boxes position if it only partially fills the boxes with beacon flux. You will need to move the blue boxes to the centered beacon using the Adjust pop up window. W1 and S2 are the ones that most likely need centering of the beacon.
• Change tel WFS to 5 msec (default 2 msec; 10 msec on W1) - make sure we see all spots on TWFS. Change back to standard observing values after.
• Check alignment of blue/red beacon on labao - make sure they are aligned properly with labao boxes. Change FPS as needed so that you see the red beacon. Use red beacon to find center of pattern then turn on blue to be sure the spots are in correct boxes. If not, move dichroic to center with correct boxes. Note that the blue/red beacons are offset by about half a box.

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.

1. Slew to star. You can turn on M7AUTO to hold the blue beacon during the slew. It will turn off at the end of the slew.
2. Align red beacon to the starlight boxes on the telescope WFS using the ALN BCN button.
3. Align blue beacon to lab WFS using ALN M7. If beacon is not in boxes, use the yellow M7 buttons on the WFS tab to get centered.
4. Focus blue beacon on labao WFS with FOCUS button. (LABAO:)
5. If needed, focus red beacon on TWFS with FOCUS button
6. Turn off red beacon and center star on TWFS.
7. Turn off blue beacon and lock star on TT only. Move TWFS boxes (ADJ popup button on obsgtk) to have star centered and evenly illuminated on ACQ hole. (Note: you might need to close DM AO loop during this step.)
8. Turn on the blue beacon and the lock star on telescope AO and labAO. Turn on TT servo, DM servo, DM AUTO, LABAO servo, and DM Tilt (the last one stays on after turning on during first slew). The message from DM Tilt will be “NOT Ignoring DM tilt…” when it is on. This may take 2 clicks to confirm this message.
9. If the coma and astigmatism terms are high on the aberration plots, create a new sky flat using the SV FLT button on the obsgtk. Turn off the DM servo, flatten, then relock the DM servo. The DM servo uses the flat to guide the optimal correction. If the signal is good on the tel WFS, it is a good idea to make a new sky flat on every star.
10. Check aberration plots. If X/Y terms are not going to zero, try stopping servo loops, recentering alignment, and turning back on servo loops. If X/Y and higher order terms still not going to zero after checking alignment and making a new flat, then this likely means a new reconstructor needs to be made.
11. SPICA uses MIRCX as a fringe tracker and MYSTIC as a fringe finder so having the STST open to monitor the IR beam quality is helpful even if you will not be doing the additional STST beacon flat alignment. Center the star flux in the Crop boxes with the CenBox button and use the drift from center, along with SPICA team input, to make beacon flat corrections as requested.
12. At times, Mircx will have such poor flux that a beacon flat correction to align to the STST reference position will be needed. This will occur on E1 pop 4 and S1 pop 5 due to their extreme distances from the telescope to the lab. Follow the SPICA team guidance in making this correction to improve the flux to keep Mircx usable as a fringe tracker with those baselines.

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:

(see STST manual for more details)

1. On mircx_super_gtk, click STS to move stage into beam path and turn on Halogen lamp. (Use stsgtk if you need to adjust halogen flux.)
2. On shutgtk, click on STST to put the stage into the beam path.
3. Open the Star Tracker gui by typing “ststrtd_gtk” in a terminal.
4. Config camera if needed. The default settings are good to Hmag 5 or so.
5. Start camera.
6. Click “Start RTD” to start the display.
7. Take backgrounds if the display is not evenly gray. Click background, wait until finished, about 10-12 seconds. (look at message at the bottom of the STST RTD to see status). The “Use Bkg” button should be green after taking backgrounds.
8. Select “Image” from filter menu.
9. Select “Load ref” to read in last saved ref box positions.
10. Set the box size to 50 pixels by scrolling in the box size window (centroiding algorithm now works for boxes larger than 20 pixels).
11. Adjust ref box positions using “Set ref” if STS light is within the boxes or “Adjust ref” buttons if STS light is outside boxes. Adjust ref will open a pop up window that allows you to select a beam and move the green box up, down, left or right with some step size.
12. When ref boxes are well centered on STS, click “Save ref” to save these positions.
13. Keep these reference box positions fixed during the night. The IR combiners are aligned with STS, so we need to align the starlight to the same reference positions.
14. On mircx_super_gtk, turn off Halogen and take out STS.

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.

1. Slew to a star of Hmag 4 or brighter (or adjust exposure time/coadds on STST as needed to see fainter stars). The Find IRC function on CD can do this quickly. Enter your desired star on a second line and hit Find IRC to get the new bright star. Close shutters as needed to avoid saturating the combiners. AUTO M7 can help keep the beacon aligned during the slew.
2. On the first slew, align the red beacon to the blue star boxes on the telescope WFS using the beacon flat. On subsequent slews (after green boxes have been set using STST - see below), align the red beacon to the offset green beacon boxes.
3. Align blue beacon to lab WFS using M7.
4. If focus term is high, focus blue beacon on labao with beacon parabola, FOCUS button.
5. Focus the red beacon if it needs it with the FOCUS button in the WFS section of obsgtk.
6. Turn off the red beacon. Make sure you have the blue starlight boxes on telescope WFS.
7. Turn off blue beacon and lock star on TT only. Move TWFS boxes (use popup from ADJ button on obsgtk) to have star centered and evenly illuminated on ACQ hole. (Note: you might need to close DM AO loop during this step.)
8. Turn on the blue beacon and the lock star on telescope AO and labAO. Turn on DM servo, DM AUTO, LABAO servo, and DM Tilt (the last one stays on after turning on during first slew). The message from DM Tilt will be “NOT Ignoring DM tilt…” when it is on. This may take 2 clicks to confirm this message.
9. If the coma and astigmatism terms are high on the aberration plots create a new sky flat using the SV FLT button on the obsgtk. Turn off the DM servo, flatten, then relock the DM servo. The DM servo uses the flat to guide the optimal correction. If the signal is good on the tel WFS, it is a good idea to make a new sky flat on every star.
10. With the star locked on telescope WFS and blue beacon locked on labAO, move the beacon flat to align the starlight into the STST reference boxes. The green cross marks the center of the box and is your target, the red cross marks the centroid of star. If the star is within the STST reference box, then click the “STST” button on the obsgtk main tab to automatically align the beacon to move starlight to the center of the reference box (use step size close to 200). This may be very slow or not work at all.
11. If the star is outside of the STST reference box, move the beacon manually. Refer to the rotation matrix wheel printout on the desktop to know which way to move. The first few clicks may not move at all due to hysteresis in the actuators. Do this process slowly, as M7 will slowly move to compensate for the beacon shift and keep the blue beacon aligned to labao. If the blue beacon did not move when clicking the beacon flat, click again as it was taking up slack in the movement. the labao DMTilt can handle up to 3 units of tilt to offload to the M7. If the values reported on the obsgtk (labao X,Y, tilt, Focus line) are lower than this, you can click again.
12. If the required move is large, ~1000 steps on the beacon flat, or about 25 pixels on STST, it may help to turn the Labao Servo and DM AUTO off and manually move the blue beacon with M7 back to center on labao until the flux is closer to the STS center. AUTO M7 can also be used for medium sized moves, ~333-500 steps or so of the beacon flat.
13. When the star is aligned on STST, tun off the DM servo and TT, move the star away, and turn on the Red Beacon.
14. Click “TOGG” on obsgtk (or “TOG BEACON” on WFS gtk) to toggle from the blue starlight boxes to the green beacon boxes on telescope WFS.
15. Click “SET” button on obsgtk (or “ALIGN BOXES” on WFS gtk) to move the green beacon boxes to the position of the red beacon. This will center the boxes over the beacon and save the new beacon flat positions in a few seconds. Watch the X,Y values of the twfs go to zero. Alternatively, you can use the buttons on the obsgtk ADJ tab pop up window to manually move them.
16. If needed, adjust focus and zero center.
17. If your target is the one you used for the STST alignment, turn off red beacon, toggle back to the starlight boxes and lock star on TWFS. Turn on TT and DM servo. Turn on DM AUTO (DM Tilt should already be on) and LABAO servo.
18. If this is an STST only star, slew to the first target and align as needed there, which shouldn't be much or at all.
19. Check aberration plots. If X/Y terms are not going to zero, try stopping servo loops, recentering alignment, and turning back on servo loops. If X/Y and higher order terms still not going to zero after checking alignment and making a new flat, then this likely means a new reconstructor needs to be made.

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:

• killall telemetry_server
• bootlaunch_master

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:

• Check aberration plots. If X/Y terms are not going to zero, try stopping servo loops, recentering alignment, and turning back on servo loops.
• Turn off the blue beacon and check the centering of the star on the ACQ hole. Adjust box positions to center star (ADJ popup on obsgtk). Hint - zoom in on ACQ display.
• Make a new sky flat.
• Look at red beacon on tel WFS and try zeroing the centroids using ZERO CENT on wfsgtk -E. Note if you are using IR combiner, then align red beacon to blue starlight boxes (not the offset green beacon boxes) before clicking ZERO CENT. Align beacon back to STST reference after.
• Check alignment of blue/red beacon on labao - make sure they are aligned properly with labao boxes. Use red beacon to find center of pattern then turn on blue to be sure the spots are in correct boxes. If not, move dichroic to center with correct boxes. Note that the blue/red beacons are offset by about half a box.
• Go back to stow and check the full beacon/dichroic alignment using the start of the night procedure. Remember to load all defaults before doing the alignment.
• If X/Y and higher order terms are still not going to zero after checking alignment, making a new flat, and zeroing centroids, then this likely means a new reconstructor needs to be made. Notify charatech (maybe try taking onsky reconstructor).