Category: MAPS

MAPS Jun. 2025A Night 1: Rotational centering

Hello dear blog friends, I’m back after being away due to beautiful, robust, inquisitive, dynamic, gregarious, exuberant, thoughtful reasons. And here we are at the MMT to observe adaptive-optically again!

The installation was more challenging than usual because both MMTO and MAPS teams were somewhat short staffed, but was still all done well by sunset.

As per usual we started with alignment. Once we got the star on Pisces (with, again, disturbingly unique-to-this-run Az-El offsets), we did a rotational centering test in order to find the chief ray. Not the one where you rotate your images and see where the star goes on the pixels, but the one where you rotate the instrument and see where the star goes on the camera. We started the rotator at -60 and went all the way to +60 — the result was a compact bean (looks kinda like this). We started the rotator at +60 and went all the way to -60 — the result was a large arc (looks kinda like this). (Images taken in strip scan mode.) The center of the bean did not coincide with the center of the arc. The arc did not overlap the bean. We saw the same behavior on the acquisition camera, so it’s not the Pisces mount wobbling. It seems the rotator itself is jumping at the start of a move. And it appeared to be when started from any initial position.

With that diagnosed and the star set to somewhat the average center, we decided to stop messing with the instrument rotator (which we don’t generally move as of yet) and moved on to WFS alignment. This included working on the fibers for the newly re-installed IR WFS, adjusting the tip/tilt mirror settings and checking whether differences between Vis and IR were due to any common optics, and finally closing up at dawn with still an open question about co-alignment. To be continued tomorrow night!

The song of the night is “The Happy Song” by Imogen Heap:

MAPS April 2025A Night 2: Toky(A)o Drift

Not a sunset picture. I took this earlier in the day (I actually went outside! It was not 100 degrees out, so I decided to enjoy the weather.)

For the first time, Bianca and I are the only AOistas at the AO station for the entirety of a run. After last night’s work, we felt motivated to close the loop. In fact, I would even say we felt confident in our abilities to do so. We began the start of the night CACAO processes while making constant WFS pupil adjustments. Normally our pupils don’t drift this much, so we decided to check the pupil imager. Sure enough, our pupil image was vignetted.

Flashback to last night:

After alignment, we worked on booting up CACAO and acquired an RM. While checking RM modes, we noticed modes were not looking AO ready. They should not have chunks taken out of them. This led us to check the pupil image. We saw the same vignetting we see today.

Not smooth RM modes. Notice the chunk taken out in the bottom right corner of each | Photo Creds: Bianca Payan.
Vignetting as a result of MIRAC being off the center of rotation.

Our solution was to adjust alignment in the periscopes and MIRAC dichroic. With the remaining time in the night, Bianca and I were able to get to the part of the CACAO process where we open up the gains gui that allows us to close the loop. At this point, we did not notice any extreme drifting. Unfortunately, we were receiving errors while trying to open the gui, and sunrise was just around the corner.

Back to present:

Just as last night, Oli and Maggie adjusted the MIRAC dichroic and top-box periscopes. Bianca and I proceed to CACAO, but continue to face the same drifting issue. We now realize this vignetting/drifting issue is very repeatable. Our suspicion is that this is due to MIRAC being off the center of rotation. To test this, we realign to the telescope chief ray to see how AO performs without MIRAC. By the end of the night we are able to close the loop on 20 modes with minimal drifting. This was a bit tricky, as we did not have a PSF to reference as we were closing the loop (MIRAC is very useful for PSF imaging). Unfortunately, we cannot easily determine how good the loop is working purely based on vibes and what we can see from the acquisition camera.

Bianca and I closing the loop on 20 modes without the MIRAC PSF.

We came to the conclusion that we do not want to proceed using MIRAC this run. Our plan is to hopefully get PISCES installed before tomorrow night so that we can continue with the optimal setup to perform AO. To be continued…

Stay tuned for the next chapter of the MAPS April 2025 run!

The song of the night is “Drift Away” by Uncle Kracker.

MAPS Apr. 2025 Night 1: Six Degrees of Freedom

It is the start of the second run of the semester. The night was focused(pun intended) on alignment and understanding how each one of the movements of the telescope, science camera, and Wave Front Sensor. And what it comes down that each one affects the other and it takes a lot of abstract scratching of head to figure out what happens when a move is done.

The Bad news this run is that the IR Wave front sensor did not make it to the mountain. But we now understand what the problem was. We have been extremely lucky that it worked at all. This is a problem that has been inherently sneaking up on us and we had never been able to figure it out. Turns out that the PCB feed through of the cryostat as it shirinks when it goes to cryo makes contact through hole mounting screws. Good news is that we have a path forward and the fix will soon be implemented.

So the hope for tomorrow night is that the wind stays slow and we get clear skies.

https://www.youtube.com/watch?v=Jn1qkf8vVQU

MAPS Feb. 2025 Night 4: Oh Connection, where art thou?

Hey everyone, I realized I didn’t introduce myself properly in my last blog post, sorry about that. I am Krishna, 3rd year PhD candidate at ASU. I am working with Jenny and Katie to characterize MAPS AO performance 🙂

It was a night like any other except we started on a little bit of rough patch. There was a brief connectivity issue with the WFS. So, the citizens of AO nation (Amali, Lauren, Bianca) worked hard with Andrew to get it back on track. It was not just this but also the WiFi that was being a troublemaker today. While this WFS issue was being worked on, Alyssa and I took organized exposures of darks and sky backgrounds at different bands.

A screenshot from Jarron showing that our ping speed of our WiFi connection was 200ms!

Eventually, after the WFS fix, it was realized that the pupil position was offset from yesterday, so we had to go to lower than 100 modes of AO correction like we did yesterday. Well, that’s a bummer.

Despite all the trouble, we were able to successfully observe 4 targets with varying R magnitudes at a constant(-ish) airmass. Hoping everything goes smoothly with the reduction, this would allows us to see Strehl as a function of magnitude (fingers crossed). We pushed as much as we can to the end of the night but clouds, once again, put a limit on our happiness.

As Sting would say – “He looked at the chart but he look in vain
Heavy cloud but no rain“

Song of the night:

MAPS Feb. 2025 Night 3: “Clear Skies”

Hello! I’m Alyssa, and I am new to this blog. I am a visiting grad student from the University of Michigan that joined the MAPS team on this 6-night run. This will be my second observing run ever!

The MAPS team headed up to the summit tonight! The skies looked more promising than previous nights.

We had some clouds here and there with periods of high winds. But that quickly died down from up to 35 mph down to 0 mph over a span of a few hours. When aligning the pupil for MIRAC5 and co-aligning with the AO WFS, we have initially found that the source position was barely on the field of view of the detector. Since there is a new dichroic lens in the optical system, Manny and I went up to adjust the actuators near the dichroic to see if we could center the source as much as possible. Luckily, this had solved the issue to a good degree, and after getting through the cloudy and windy moments in the night, we were fortunate enough to start taking some science data tonight with some targets.


With some progress tonight, I want to take a moment for some notable quotes given out from none other than Krishna:

“What is the name of the dog in Scooby-Doo?”

“Is the loop looping?”

“Also, Manny, you look like a Rapper.”

Krishna
Manny and Krishna strike a pose as your local MMT rappers
Manny and Krishna pose as your local MMT rappers

Song of the night featuring one of my favorite bands:

https://www.youtube.com/watch?v=yhWWlFme0dU