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Last updated 11/25/2023
New Alignment Procedures - no longer updated - see alignment sections on this page
Night-time POP Changes - includes how to trouble shoot pop not moving
Shutting Down prior to a Power Outage
Recovering from a Power Outage
Text Commands for CHARA GUIs
Daily Alignment Check Procedure
Co-phasing with the CHARA phase reference
Instructions for using the Six Telescope Simulator (STS)
Six Telescope Star Tracker (STST) Manual
Tip-tilt Splitters Change
E1 HuT and Cooler Communications Recovery
Coude alignment procedure - Updated 2021Jun01
Telescope Horizon Limits
Daily Aberration Plots
ADAPTIVE OPTICS DOCUMENTATION
Tuning the AO Systems
E2 AOB Dichroic Recovery Document
Using Labao with Starlight
Telescope AO User Manual - an engineering manual, not for observing
WFS TT Alignment and Usage
TWFS Faint Object Instructions
Check the current conditions and weather forecast for Mount Wilson before opening any of the domes or telescope covers. The telescopes can be closed in about 5 minutes from the control room. With this in mind, don’t open up the telescopes if conditions can change for the worse rapidly enough that you don't have time to close down safely.
Weather stations are installed at each bunker; readings are listed on the weathergtk. The HPWREN cameras are also useful in monitoring local conditions. However, nothing beats going outside for a gander and giving the sky a good old fashioned assessment.
Weather variations do exist from telescope to telescope, as much as 20% in RH at times. Most of the time this just means something is blowing through and opening is not a good idea. These circumstances need to be dealt with cautiously depending on the given weather conditions. Allowing extra time to close is advised in case of any problems.
Other humidity warning signs are: 1) water dripping oﬀ the OPLE building (or wet spots on the asphalt straight down from the eaves); 2) cold, clammy feel to metal objects such as railings; and 3) dew forming on the parked cars. It is important to note that the humidity can rise from 50% to 80% in as little as 10 minutes, so keep a close eye on the rate of change of the humidity plots. It can also rain or hail from small, passing clouds when the humidity is quite low, even 30% RH or lower. Operators have been surprised before by small puffy clouds in unsettled air with low humidity. If in doubt, stay closed. The HPWREN webcams are a good resource to view the bottoms of clouds. If there is any virga, the clouds are holding moisture and try to rain out. Stay closed if you see anything streaming below the clouds.
Gauging the airborne dust and pollen can be problematic because you need a bright light and a relatively dark night. In general, you want to look in the bottom 0.5 meter of the light column. There will be a diﬀuse column lit up by the beam – don’t worry about it, just follow the dust glints. If you can count the dust glints, the conditions are safe to observe. If it looks like a blizzard, close up. If any of the dust glints shine with an orange or a peach hue, or the dust glints look abnormally large, the dust is probably ash – close up immediately. Ash seriously degrades bare aluminum coatings. Dust and wind go together. But, just because it is calm, the dust conditions might still be bad. If it was windy a few days earlier, it could have kicked up a lot of dust, which can take several days to settle. Finally, during late spring to early summer, conifer tree pollen can be problematic. If particulates are borderline please email the CHARA day staﬀ so they can clean the optics as soon as possible.
Wind will degrade the seeing and kick up dust. The wind eﬀects are ampliﬁed in the tunnel between the OPLE building and the oﬃce building, so look for other places to gauge the wind conditions. The intersection of the road and the trail to the eastern telescopes is a good place to gauge conditions. If you can hear the gusts from your desk, whistling from the light pipe supports, or the chain banging, it is too windy to observe. Occasionally you will hear the wind rustling the tops of the tall trees, but it is calm at ground level. This is a symptom of chaotic wind conditions, and almost always happens during windy episodes (Santa Anas, onshore ﬂows, etc.), during which you shouldn’t observe – the seeing will be bad anyway. Be cautious about opening if wind gusts are above 15-20 kph; winds this high are usually correlated with bad seeing and poor data quality. Telescopes and domes should be closed if the wind gusts get up to 30 kph. This will protect the optics from branches and debris that can be blown in from the surrounding trees.
If there is snow stuck to the telescope dome itself, don’t open up. If there is snow still on the trees and branches procede with caution and make a visual assessment.
Cold temperatures around freezing also can be problematic. Several components are not rated to operate at freezing temps. Do not open unless it is above freezing and keep an eye on the temps if they are still dropping. Here are limits for observing close to freezing:
A high-powered infrared laser is used for the delay line metrology. This is an eye hazard, so before entering the lab check to make sure the red light above the door is not on. If the laser is activated, you must wear IR-protective goggles. Please note that the METLAS gui or OPLESystem Controller gui may not show the correct state of the laser. Hit reopen on the METLAS gui if it does not agree with the others.
Lab booties/shoe covers must be worn inside the lab. Throw out booties that have holes in them. The traction tape on the steps are particularly rough on booties so examine them before and after using them. Proper clothing is also important. Loose hanging jackets or garments can snag on mirrors or other exposed equipment and are better left outside of the lab. Please be alert and move slowly and cautiously. When entering the lab make sure to walk across the sticky ﬂoor mat. If the mat isn’t sticky, remove the top layer. If this is close to the ﬁnal layer please notify the staff.
Minimize the number of people in the lab, especially if within a few hours before observing time. Many bodies can create unwanted atmospheric eﬀects. With too many people, it is too easy to bump into each other and the equipment. If you bump, hit, move or just tap anything in the slightest way, let staff know. Never touch anything you have not been trained to use. If ever in any doubt, leave it alone and get someone who knows. Any unusual sounds, sights, movement of equipment, etc., should be noted. You must know the path of the laser beams, metrology or alignment.
When leaving the lab any time of the day, remember to turn off all lights (fluorescent and incandescent). Lights left on generate unnecessary heat in the lab.
Begin opening telescope domes and enclosures at least two hours before sunset (when the sun is below 40º).
Before opening the domes, make sure to check the current weather conditions and the forecast to make sure conditions are safe to open and are likely to be stable as you wait for it to get dark.
To vent the domes (open partially, usually during Summertime):
To open the dome slit fully:
Day time staff will align the lab during the week, but operator is responsible for alignments on the weekends.
Before doing alignments, home LDC's (as of 10/12/23 - update if no longer needed)
If alignments have been done, check the following:
If the observer will be observing bright targets and requires the use of the aperture wheels, the power cord needs to be plugged in.
NOTE: If using W2 E2 S2 for Classic or PAVO, then W1 E1 S1 ople computers have to be turned on as well in order to turn on the electronics for the pair, even if you don't plan to use them.
There are six computer screens. Top Left is screen 1, bottom left is screen 2, top middle is screen 3 and so on. Window layouts can be saved and reloaded to suit each operator. Use the third icon from the left in the toolbar (Operator Layout) to open a window to save or load a layout.
M10 and red beacon alignments can get started before ople system controller is on and before UT 0 because the scope servers are always on. Will need labao servers (after UT 0) to do labao alignments. Remember to restart scope servers. Ople system controller is needed for the carts, not alignments
Servers can be opened from the black menu at bottom of screen 1
See also Night-time POP Changes which includes trouble shooting notes if a pop mirror does not move.
Check that pops are set as the same pops as the setup request email before homing the carts
Manually Moving PoPs during Popperi movement
The initial beacons alignments are done with the telescope at stow with M7 in the default position. 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.
Make sure the carts are not near the front (0-5 meters) when performing these alignments or the labao alignments will be off.
IMPORTANT NOTE: There are now two sets of boxes on the TWFS.
At the beginning of the night, the red beacon must be aligned to the blue starlight boxes with the telescope at stow. You can zero out any offsets between the green beacon boxes and the blue starlight boxes on the telescope WFS using [ZERO] on obsgtk or [ZERO BCN] on wfsgtk.
Check higher order terms - look at abberation plots or at terms displayed on the wfs gui.
Checks to make sure beacons are aligned properly to TWFS:
Aberration plots: Keep aomon open during the night to montior the aberration terms. If twfs terms get large, do the ZERO CENT procedure.
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 save the beacon position after the STST alignment. 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 use the Six Telescope Star Tracker (STST) to align the IR starlight in the lab.</font>
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.
It is typically dark enough to lock on your first star roughly 25 minutes after sunset or the time of twilight reported by Cosmic Debris.
If the first science target/calibrator is faint in V-band, slew to a brighter star to initialize the telescopes, make flats, and do STST alignments.
Slewing to a Target Using Cosmic Debris
Locking on a star involves aligning the beacons, locking the star on tiptilt and tel AO, and locking the blue beacon on labAO. TelAO performs fast correction to compensate for atmospheric turbulence. LabAO performs slow correction to compensate for non-common path length errors along the beam path from the telescope to the lab.
Note: W2 does not have a DM installed at the telescope yet (no telAO, only labAO).
The path of the visible and IR light into the lab is different because of atmospheric refraction and dispersion in the AO dichroic. Below we outline alignment steps separately for visible and IR combiners. For IR combiners we use the Six Telescope Star Tracker to align the IR light in the lab.
While tracking on a star, labao will offload X,Y tilt to M7 to keep the the blue beacon centroids aligned to labAO WFS. There are two methods for doing this:
Old method: DMTILT is gray (reconstructor ignores tilt). M7AUTO will adjust M7 to keep blue beacon centroids aligned to labAO WFS.
New method: DMTILT is green (use tilt when computing reconstructor - “Not ignoring tilt”). DMAUTO will use labao DM to correct for tilt and offload to M7 to avoid reaching its tilt limit.
STOP A: If needed, the 3 STOP A buttons on obsgtk will stop any alignment sequences in progress.
New procedure (as of 10/12/2023) to offload aberrations from the W2 telescope WFS on to the labAO DM. This should provide better corrected images on W2 until we get the DM installed at the telescope. Must be done after every slew. Follow these instructions:
For the visible combiners the red beacon and starlight will be coaligned, so you only need to use the blue starlight boxes on the telescope WFS.
Obsgtk, main tab, [ZERO BCN] at the start of the night to clear any offset between the position of the beacon boxes and the starlight boxes to avoid any confustion
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 offset red 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.
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.
Faint stars (H > 5 mag) will not be easily visible in STST. Therefore, before slewing to the first star of the night or when slewing to a different region of the sky, slew to to a nearby bright IR star to align the beacon flat and set the beacon box offset on the TWFS. Then slew to faint star, keeping the red beacon at the same fixed position.
NOTE: The STST centroiding/servo'ing now works for longer exposure times. If you change exposure time, you need to: stop the camera, config the camera, restart the camera, and retake backgrounds.
For H=6 mag, try changing coadds to 5 or 10 for 1 sec integration.
For H=8 mag, centroiding has been shown to work using 50 sec exposure (1 coadd).
*Please update here* if you determine settings that work good for the using the auto STST alignments at different magnitudes.
To align STST, slew to a star of Hmag 4 or brighter (or adjust exposure time/coadds on STST as needed to see fainter stars).
For programs with bright IR stars, skip align beacon, but do the M7 and labao focus alignments. Then lock the star on the blue boxes and use the STST to fine tune any misalignment of the beacon flat. Check the beacon focus on the twfs occasionally to make sure it stays near zero, every 2-3 stars.
If AO performance is bad try these steps in the following order:
The starlight is typically missing from the edge rows of the TWFS on S2. This is likely caused by an alignment problem at the telescope/AOB. We are able to get improved performance on S2 by applying a threshold to ignore the TWFS boxes on the edges without flux. Here are the steps to try this approach again on sky:
Theo added a routine to offload aberrations from the W2 telescope WFS on to the labAO DM. This should provide better corrected images on W2 until we get the DM installed at the telescope. Follow these instructions:
Always pay attention to where you are slewing next to avoid not passing the limit switch correctly and dealing with scopes getting stuck near 90° or 160°.
There are two limit switches negative and positive near 0.
It is okay to slew completely past 0 in either direction.
However, if you slew close to zero either from the east or west, it is possible you will hit just one limit switch.
If you don't pay attention and only hit one limit switch at 0, some or all telescopes will continue to stall near 90 or 160 degrees and it is a pain to fix.
Got to Troubleshooting, “Azimuth Limit Switches” Section
If you need to send a telescope to a different star while keeping the others at their current position, in the scope server, type in the star name (use a space instead of an underscore), press enter, then type “next” and enter.
Initialize the pointing of the telescopes on your first target by going to the MAIN tab on the obsgtk and clicking the red [INIT] button. Make sure you are on the correct star before initing the scopes or you will have problems. This may have to be repeated if the pointing drifts during the night. This will allow more consistent and accurate pointing for this part of the sky. You can also INIT during the SKY frames on MIRCX and MYSTIC since the star is in a good spot for finishing a slew.
When running MIRCX/MYSTIC, the operator may want to have the windows open to follow the fiber mapping, scanning for fringes and data recording. The windows can be opened with the command mircx_launch_all_guis on a desktop terminal. It will open 5 windows for each combiner, but they do not need to all be open. Close what you don't want to monitor. The fiberexplorer, gdt, rtd, and super_gtk windows are most helpful.
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).
With the star aligned with the acquisition ticks, check to make sure there are counts on the TipTilt server or the white plots in the TT windows have condensed.
The End Night sequence on Cosmic Debris can be used to end observing and stow the telescopes, carts, and domes and close the mirror covers. It will only stow the active scopes, carts, and domes, so if there are other scopes open, make them active in the Configure tab of CD or stow them manually with the procedure below.
Obsgtk: “Hut….Error: Relative move error -12”
If you start to notice that buttons aren't doing anything (usually on E2) such as moving the beacon or turning on the red beacon, try doing one ~1100 step move to the beacon. If you get a “Hut….Error: Relative move error -12”, need to recycle the aob and restart hut.
On obsgtk, if the telescope wfs goes black, the wfs server has crashed.