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MAPS May 2024A Night 6: Windy IR WFS CACAO/DO-CRIME

A good final night to an excellent run!

Tonight was our last night this run. I’m really happy with all the progress we made! It was definitely helped by the fact that this is our best-weather run ever, with the highest percentage of useable time: We were open for 5.6/6 nights, or 93% efficiency!

We observed Arcturus with CACAO until transit, took a 4-hour break due to high winds, and then observed Deneb with DO-CRIMES until transit.

We solved many problems this run (don’t worry, we also discovered new ones). Jarron fixed his BLINC issues to get a good pupil on MIRAC and he and Jared even got its display on the AO computer so we successfully fulfilled our dream of using MIRAC as a high-speed PSF viewer for AO. MMTO’s Ben and Tim got us aligned to the optical axis (again) but this time we worked hard to all understand each others’ terminology and tolerances so that when we do it again we do it right. Brian kept us safe by monitoring the wind limits. Grant (in-person), Oli (remotely), Bianca, and Manny got the dichroic and periscope re-aligned so we had good AO pupils. Amali poked the edge actuators until they listened better. Amali, Jared, Olivier, Andrew, and I got CACAO working with both the Vis and IR WFS’s. Bianca, Lauren, and Orlando learned more about the Top Box. Jacob and Suresh got DO-CRIMES working with 20 modes and optimized gains. Manny supervised us all and provided insight about all our hardware issues. Dan and Ruby installed (with the help of MMTO day crew) and connected MAPS and I got to see that side of the operations. And the MMTO staff provided a clean and cozy lifestyle. Thanks to all!

Wind plot at twilight — we were closed from 11pm-3am but got back on-sky and did CRIMES! Our wind limit is sustained above 30mph and/or gusts above 35mph.

On this last night we focused on the IR WFS and trying to understand our hardware problems that we’ll need to fix for next run, as well as to try and get a 20 modes comparison between CACAO and DO-CRIMES. Unfortunately the MIRAC dataset we took with the CACAO loop was pointing into the wind and just when we realized we had to close, and we weren’t able to get a better one. The DO-CRIMES dataset was in better conditions, but they may not be identically comparable. As far as the hardware problems go, we rotated the instrument rotator by 60 degrees and saw that the raggedy edges of the pupil rotated too, therefore (at least in the IR WFS) they are more due to the ASM than to pupil misconjugation. We didn’t have time to switch back to Vis WFS and try the same test, so we should do that next run. The contamination has definitely been a problem and will have to be removed before the next run.

IR WFS pupils before and after rotating the instrument rotator by 60 deg.

The best 15 minutes of today were around 3am after we saw that the wind was steady below our limits and we got to re-open. This was a first for Jacob and very much need as it enabled him to get that last bit of DO-CRIMES testing and data!

The song of the night is “Hold Me Closer” by Elton John & Britney Spears (2023)

MagAO-X 2024Ab Day 13: When the rain starts bouncing, you know it’s bad

This is my seventh trip to Las Campanas Observatory (I think?) and the first time I’ve seen actual, bona-fide precipitation in the Atacama desert. I woke up at 2pm to the gentle patter of rain on my windows, and emerged blinking into daylight. I did try to document it with my phone, but in my sleep-addled state I apparently double-tapped the “record” button and ended up taking some neat videos of the ground.

Fortunately, the early shift was up and could take some pictures.

This would be the spot for a lodge hot tub (Photo by Eden McEwen)
Snow, snow, go away… (Photo by Eden McEwen)
Over to the west we have some low cumulus and to the east we have oh my god run it’s coming (Photo by Logan Pearce)

Vizzy Viscacha was wise to stay under cover as the storm rolled in. Even MagAO-X had to be tucked in safe and dry.

Note that additional measures were taken to ensure MagAO-X aridity. (Photo by Laird Close)

Then, it started really snowing.

Optical depth illustrated (Video by Laird Close)

Laird is the only one brave enough to venture forth from the lodge. He had to get MagAO (not -X) packed up for its international shipment.

Where is the sciatic nerve, anyway? (Photo provided by Laird)

After the snow, we got a snow-bow!

I should request a room change. It’s not fair that the rainbow is only at the La Silla apartments.

Unfortunately, our guest observers Gabriele Cugno from Michigan and Jensen Lawrence from MIT have had just about the worst weather I’ve ever seen here. In fact, this brief break in the clouds after dinner was when Gabriele got his best chance to observe:

Finally, some stars! (Photo by Logan Pearce)

Then the hailstorm started.

(Or maybe it was a graupelstorm?)

Today, by the numbers:

New SSH/VPN questions: 2
Spurious Python environments purged: 11
Night lunches recovered from shutdown: 4
Stars: 14 ish?
Hailstones and/or graupelstones: ≫14
Adaptive secondary mirrors: 1 (slightly used)

Best 15 Minutes of the Day

Probably the rainbow. I swear, natural phenomena here look just the way they are depicted in children’s book illustrations.

Song of the Day

This song of the day is not observer-approved.

“Only Happy When It Rains” by Garbage

Remarks overheard

“So, by the way, how does a pyramid wavefront sensor actually work?”
[rueful laughter in response]

“Whatever. I have no excuses, but I’m also not sorry.”

MAPS May 2024A Night 5: Conjugate planes

Our science cameras image the star in the focal plane, and our wavefront sensors image the star in the pupil plane. A conjugate plane is where your alignment needs to be in order to get those images in focus. After tonight we are wondering whether our VisWFS pupils are conjugate to the telescope pupil.

Summed VisWFS pupils. Why aren’t the edges sharp? Why are the edges raggedy? [Image description: photo of a camera display, black background, white photons in four imperfect images of the telescope pupil, which is round with a hole in the center like a doughnut.]

Tonight we started with Do-Crime on the IR WFS and MIRAC photometry, then moved on to CACAO on the VisWFS when Jared and Olivier called in on Zoom. We first closed the loop on the 50-modes response matrix from yesterday, and it still worked to the extent that it tightened up the PSF!

We next wanted to explore why the higher-order modes had been unstable and why our pupils still looked raggedy and soft on the edges. Because we had trouble calibrating the edge actuators of the ASM in the lab, we have always blamed the edge weirdness on the imperfect ASM calibration. However, tonight we decided to try a Hadamard matrix diagnostic, which pokes each actuator individually (but efficiently) and measures the result on the WFS. The result was that some parts of the mirror were having no effect whatsoever on the wavefront. One of those regions was where the shell is contaminated, but there were other regions too. Even after Amali put some disabled actuators back in the loop, the result was the same.

Olivier started wondering aloud whether our pyramid image was actually conjugate to the telescope pupil. If it’s out of focus of the pupil plane, then the response would no longer be linear, and you would also get mixing of phase and amplitude of the electric field. This could explain why the pupil images don’t look sharp or round.

We did a test where we translated the star about an arcsecond away from the tip of the pyramid, and saw the pupil image shift by around 4 pixels. The shape of the central obscuration changed too.

Left: Four pupil images on the VisWFS evenly illuminated when the star is centered on the tip of the pyramid. Right: After we nod about an arcsecond to put most of the light in the upper right pupil image, the image has shifted a few pixels. If the pyramid was conjugate to the pupil of the telescope, then they shouldn’t have moved.

So we switched to the IR WFS to see if we could see a similar shift. The IR pupils look sharper than the Vis, and they didn’t shift much if at all.

Left: Four pupil images on the IR WFS evenly illuminated when the star is centered on the tip of the pyramid. Right: After we nod about an arcsecond to put most of the light in the upper right pupil image, the image didn’t seem to shift much. So the IR WFS seems to be in better focus to the telescope pupil.

This was about as far as we got with CACAO before it was time to switch back to Do-Crimes. Tomorrow night we will use the IR WFS and compare CACAO and Do-Crimes corrections.

The song of the night is “Gimme more” by Britney Spears (2007)

The best 15 minutes of the day were flying a kite with Amali, Manny, and Bianca. It’s a homemade kite made by Amali, and the gusts across the peak and around the dome are not very laminar, so it was hard to get a sustained flight, but we did get it to dance and dive in the wind. And we also had fun trying but failing to see the green flash again.

Amali flying the kite.
Bianca flying the kite.

That leads us to the bonus song of the night: “Let’s go fly a kite” from Mary Poppins

MagAO-X 2024Ab Day 12: Lost Socks

I was home in Tucson for about 5 minutes after the last run. So I only managed to get all of my laundry done all at once just in time to pack for this trip. Upon doing so, I discovered that I was missing some socks. This happens to all of us, dryers being constructed the way they are, and I normally don’t expend much energy on it.

However, this time one of the lost was a brand new wool sock I bought especially for LCO, and I knew I was headed into this:

So I was disappointed to lose my new sock that I’d gotten to wear once or twice on the last run (and an older one too), and worried about potential for cold feets.

But then I did my first round of laundry, and had the bright idea to look in the cupboards above the washing machine… AND I FOUND MY SOCKS YOU GUYS!!!!!

Only problem is now I have a two mismatched single socks on two different continents.

Thanks to whichever denizen of LCO took the time to stow my socks for me.

We had an impromptu birthday celebration for Logan tonight, organized by Eden. Singing, dancing, homemade card, and fruit snacks for all.

Happy Birthday Logan!

Laird has been busy packing up the venerable MagAO ASM, getting ready to send it on its way to its new life at the LBT. I booted up the old control computer for MagAO-C, and it came right back to life.

Lots of nostalgia in this pic!

Being weathered out has some advantages. Olivier made us a new toy, which lets us look at the timing of our system in 3D. This movie shows the response of the MagAO-X wavefront sensor to a deformable mirror (DM) poke as a function of time. Key fun feature: the DM actuators move in a raster pattern, and it takes about 100 microseconds for the whole DM to move. You can see that in this movie.

purple stylings by Joseph
The clouds have made for some nice views with interesting relief highlighted all around us

Best 15 minutes of the day was plugging in the MagAO computers and remembering how it all worked, seeing them boot again, figuring out how to remember the password, and logging in to see an old friend.

MAPS May 2024A Night 4: CACAO 50

We made a lot of AO progress tonight! We switched over to the VisWFS and CACAO, and started with measuring latency (mlat). Jared and Olivier joined us on Zoom and helped debug some settings that were causing us to think our hardware latency was noisy and to suspect timing issues or simlinking the slopes instead of the pupils, but now we think it was actually just a normalization. Here is a nice mlat we got:

Screen grab of the AO control computer while taking hardware latency (mlat) measurements. Top left is the pyramid pupils, small plot to its right are the slopes, medium plot to its right is the DM display, terminals in upper right corner are CACAO, ASM GUI is in lower left, gain GUI is in lower right, and the gnu plot at center bottom is the mlat result: The purple curve is from earlier in the night before restarting CACAO and getting rid of our settings, and the green curve is the new mlat result after debugging the noise/timing/simlinks/settings.

After the mlat’s, we closed the loop on the first 3 modes with our best response matrix from March. It worked!! But we couldn’t do higher-order modes — probably because the pupil and alignments had changed. So we moved on to take a new response matrix, but closing on the first 3 modes using the March matrix. We also tested tip/tilt offloading to the mount. And after some investigation of why some of the modes looked noisy or didn’t have much power in them via plotting self response matrices (selfRM), we continued and took a 50-modes calibration. We closed the loop with it and (even though we had to put tiny gains on modes 37-50), it was actually correcting and improved the PSF!

It was cloudy this afternoon and there were a few patchy clouds at sunset, but pretty soon it cleared up and we had a nice night with seeing around 1-1.3”. Earlier in the day Jarron opened the warmed-up BLINC and removed the baffle that was vignetting his pupil, so tonight we all had good pupils for the first time and we were able to get some nice looking PSFs!

When Jared and Olivier went to bed it was time to end our time with CACAO for tonight, and switch to Jacob and Suresh’s project with DO-CRIME and the IR WFS. We finally ended at dawn, a very full and useful night!

The best 15 minutes of the day were trying to watch the green flash at sunset with Amali, Lauren, and Bianca. (We didn’t see it though, but we used the trick Gill taught us.)

The song of the night is “Toxic” by Britney Spears (2004)