Katie Morzinski – Page 2 – Extreme Wavefront Control Lab

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 Aug. 2024B Night 2: Unstable

Tonight we first took a bunch of ASM latency measurements with different tuning parameters for Jess — took about 3 hours to get 5 iterations, may do more tomorrow night. (Well, this was after being closed for clouds for the first couple hours of the night, same as last night.)

Then we moved on to CACAO calibrating and testing. Amali tried closing the loop using the response matrices from last night. The 20 modes one worked OK, but the 50 modes one was quite unstable even at medium modes (10 and up). So then we tried median combining them and looking at them here. In the following plots we have 5 iterations of the 50-modes response matrix, and the 6th frame is the median. Tip looks OK, tilt looks OK, and focus looks OK. But they also have odd higher-order signals that AREN’T averaging out. Like the bright white or black volcano. However, these 50 modes were taken with the 20 modes loop closed, and what if that was introducing some noise? So now we are trying going back to the 20 modes response matrix and doing more iterations to average those. For the 20 modes response we are closing the loop on tip/tilt at 0.30 gain and on focus at 0.15 gain. We’ll just keep doing these until sunrise, then average them and try them tomorrow night.

Oh and Yoav had to run up the hill away from a bear as he was coming up to the dome from the Bowl tonight.

The song of the night is “Stressed Out” (Acoustic version) by Twenty One Pilots:

MAPS Aug. 2024B Night 1: We’re back!

Last night was the first night after the summer shutdown and despite the forecast we were open for most of the night! We’re using MIRAC as the PSF viewer and found the first star pretty fast!

We aligned the pupil, tested the rotational centering, tried the -300mm and -250mm lenses in front of the VisWFS and decided to go with the -250mm lens. Then we took mlats and then many iterations of CACAO testing. Rebooting RC3 and taking care of some of the over zealous logging seemed to help with issues of the CCID-75 seeming to pause or hang. The low is around 60deg F and the ASM sometimes gets close to overheating, so we take a short break and allow it to cool down. The night ended with a hot ASM at the first twilight.

The song of the night is “Peaches” by The Presidents of the United States of America:

MAPS Jun. 2024A Night 7: Final day and night

Today was the last day of SPIE Astronomical Telescopes & Instrumentation 2024 and tonight was the last night of MAPS June 2024A.

Joseph gave a nice talk (second-to-last of the conference) with MagAO-X data:

Joseph Long giving a talk in the PSF reconstruction session.

Meanwhile at the MMT we tested our previous CACAO calibration, took a new one in better seeing, practiced both Bianca and Lauren running CACAO, and were in the process of more testing when we had to close the dome due to high winds. We waited around until finally calling it a night and a run around 2:30am when the winds continued rising and the clouds came up too.

Here’s our pretty good CACAO loop with 50 modes.

We keep asking Tim and others from MMTO to explain the hexapod to us, but we still don’t understand some of the behavior we see. Last night we had the focus pushed to the limit (near +1600 um), even to the point where the LUT wanted to offload coma but couldn’t send it. So last night we tried starting over: We put the focus to +800 um, let the LUT run for a little while, and lo and behold we were way out of focus. As we focused by eye we ended up back near the limit, around +1600. Tonight, on the other hand, we’re around +700 um and we’re in focus. We asked Brian if the temperature correction is very different and it’s not — well it’s about 50 um different, but that’s not enough to account for the focus difference of around 800 um.

Thanks for a great conference and observing run all!

The word of the night is 満月 (Mangetsu) which means full moon.

MAPS Jun. 2024A Night 6: Pupils, CACAO, and ARIES

Today/tonight Dan and Amali went down, Dan and Oli came up, and Craig and Oli went down. Oli brought up six (6) new negative lenses ranging from f=-100 to -1000mm to test the Vis WFS pupil focus. We took another image set with the current lens (f=-300mm) and then swapped it out for each of the other lenses to see the difference in pupil focus and pupil size/separation. Here is what we saw:

Negative lens test, in front of Vis WFS.

Result: The best are f=-200 & f=-300. Oli’s feeling is the best focal length is going to be around f=-250mm. That lens is not available but can be created by combining two lenses. Furthermore, there are other degrees of freedom that can be used to fine tune… namely the separations between the CCID75, CTL, and Pyramid. By adjusting those distances, the overall magnification (pupil size and separation) will change. This is a much more complicated alignment and is destructive since a move cannot be perfectly reversed. So we may try that another time.

Meanwhile we took some ARIES spectra, then went on to closing the CACAO loop with 50 modes and saving some ARIES images. Unfortunately the seeing was around 2-3” so these won’t be great, but it was also a really good practice session for Lauren and Bianca to run CACAO while Amali coached them remotely from Tucson.

There was a dust storm blowing over from New Mexico. Around 3:45am it got worse, and meanwhile the seeing had blown up to above 3” where we were unable to make much progress anyway, so it was time to close for the night. We have 1 more night but the forecast doesn’t look promising, so we shall see.

The word of the night is TEAMWORK. The MAPS team has done a great job this run covering the various tasks even though various people have had to come and go due to life circumstances. Thanks for the excellent teamwork, MAPS team!