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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)

MagAO-X 2024Ab Day 11: Cloudy but fun week

There were new faces this time so I am going to introduce myself. I am Carla the youngest Magellan operator eh eh. For now at least.

My week with you guys started on Monday, when I realized you are at the mountain and thinking about the treat I am going to get you this time. So, just before going to El Pino I brought a couple of “dulces chilenos”. I see you like the alfajores and that’s a very typical Chilean dessert filled with the best sweet of all, manjar.

It was a week where we were closed almost all the time, the telescope was open only 22 hours! So that’s kind of a record for me. But it was a great opportunity for me to spend time with you and laugh at your very funny way of being. I appreciate your spirits.

This time I tried an artistic empanada day photo.

Actually tonight you get the famous picture with the 6.5mts mirror, and I have to admit I can’t believe you didn’t have it before, so it was good. You have the best poses, so of course I copy one of them and get my own picture, thank you eh eh.

Then, we saw the auxiliar building where the mirror is aluminized and got the other instruments ready. It was fun to have this tour. We can repeat these pictures in the future with the other part of the team of course, if the weather allows us.

AOX team and me with Clay’s mirror.

I get to know better about the work individually you are doing here, so for me it was a very informative week, and I want to congratulate all of you for your amazing and dazzling job you are doing for astronomy. Thank you very much for sharing this with me, you blow my mind.

I hope you have a good rest of the run and take good care of yourselves, especially on the cold nights that are coming.

My favorite 15 minutes of the week was going downstairs and tasting all of the new candy. My favorite was the chocolate eggs and the ones I couldn’t even try were the wasabi ones. I hope to bring you the real merkén next time.

The Song of the Day

A very old song but it is a good opportunity for you to get to know the great Cecilia, also it’s a song that will cheer you up during this very cloudy night.

MAPS May 2024A Night 3: Alignment Crimes

Cell phone photo (!) by Suresh of the Milky Way over the MMTO last night. [Image description: a star-filled sky, and a cloudy-looking galaxy band, over a telescope dome on top of a pine-forested mountain.]

The nice thing about observing at the MMT rather than Magellan (even though they don’t haul food, meal prep, cook, nor clean dishes for us here) is that when you have an urgent need for one of your engineers to come up, it’s only a 2-hour drive (rather than a 2-day flight/drive) from Tucson! Tonight Grant kindly came up and got us aligned.

Why did we need to do alignment again? Well between the telescope and the AO bench we have so many degrees of freedom, and the telescope staff that we work with have different ideas about what to do, and our team has different ideas about what to do, that we had gotten very misaligned and had to start all over again. As I mentioned yesterday, Tim and Ben got us aligned to the chief ray of the telescope. Tonight Grant, Oli (remotely), Bianca, Manny, et al then went back to our first upstream optic: the dichroic — and starting there did a beautiful iterative alignment (even having to move the MOUNT of periscope 1 because it had run out of range) and got us filled pupils! (Especially after Amali also encouraged some of the edge actuators to do a better job holding up their edges.)

Yes we are still a bit unclear as to why the dichroic was so far off (since we hadn’t touched it and we THOUGHT we were on the chief ray in January when we installed/aligned it), and why periscope 1 had wandered so far. But I think it’s just a complex system with many parts controlled by different teams and we have different staff (both from MMTO and MAPS) at different times so we never quite know if we are doing things the same way every time, no matter how hard we try, especially since the system is still so new and we are constanly making adjustments and working out kinks anyway.

So we will continue to learn more about the situation, but thanks to Grant for coming up and Oli for being on the phone and to everyone for filling our pupils once again!

Grant looking at pyramid pupils on a laptop at the Cass of MMT in the dark. [Image description: Grant is peering at the pupil image, and about to reach in and adjust another optic and watch the change.]

After this we went on-sky and Andrew got the IR CTL pupil tracking working! And then Jacob and Suresh took Do-Crimes interaction matrices and closed the loop with a 20-modes loop! We were debugging this at dawn when some patchy clouds suddenly showed up (after a beautiful clear night with 0.8-1” seeing) and so it was time to call it a night (It’s a night!).

Amali’s completed Tunisian crochet project! [Image description: A scarf is draped across 2 chairs. The scarf has a geometric pattern that morphs into the word “MAPS” and has colors of dark blue, reddish-orange, and whitish-cream.]

The best 15 minutes of the day were one of my trips up to see the alignment in the dome.

Song of the night: “I’m a Slave 4 U” by Britney Spears (2001)