Tag: MIRAC

MAPS/MIRAC Mar. 2024A Night 2: Tunisian crochet

Tonight started cloudy and even with a little precipitation! (Which we just can’t bring ourselves to actually complain about, being children of the drought-stricket desert southwest.)

Image description: A closed telescope dome in front of thick clouds on a rocky mountain peak, with snow amongst the rocks and fluffy-looking pine trees in the foreground.
Image decription: Same closed telescope dome from a different angle, with thick clouds in the sky, and the red light of dusk making the mountain ridge redden as well.

So it was time to learn some Tunisian crochet, courtesy of a book authored by MAPS and CAAO colleague Lori Harrison: Exploring Tunisian Crochet: All the Basics Plus Stitches and Techniques to Take Your Crochet to the Next Level; 20 Beautiful Wraps, Scarves, and More.

While we were clouded out, I called in to the MagAO-X run to eavesdrop for a little while on the MagAO-X AO GUIs:

Finally the clouds cleared up around 11pm and we went on sky! Only to have trouble finding our stars. We even pointed at the moon (which is 31 arcmin in diameter) and we could find that! But we tried to focus on the limb and just weren’t able to get the adjustments we needed to sharpen it up. This was all most likely due to the primary mirror cell throwing an error with a garbled measurement that was causing an unknown piston and tip/tilt that we just weren’t able to take out with pointing the mount and focusing the hexapod. We do wish our cameras had a larger field of view to help with finding stars when there’s a trouble issue like this, but ultimately it seemed we didn’t even have the range to take it out.

Meanwhile MIRAC was still working on adjusting its pupil alignment, which was actually a fine thing to do when all you can see is the sky (but no stars). This time Manny and Rory went up and turned one of the screws on the bellows, with little effect. We also tried rotating the instrument rotator, and were gratified to see it did indeed rotate the one bright spider we could see, but still did not help to center the telescope pupil with the MIRAC pupil. Ultimately we had to call it a night around 2am.

The song of the night is the sound of water dripping from the trees.

MAPS/MIRAC Mar. 2024A Night 1: Optical alignment

While the MagAO-X run is going on in Chile, your friendly neighborhood MAPS/MIRAC team has just summited Mt. Hopkins to run CACAO and take data on this side of the planet. We spent a lot of time trying to align our pupil planes and focal planes and WFS and science camera.

TopBox GUIs with ZWO pupil image (left) and Basler PSF (center).

The MIRAC pupil was still misaligned so we went to zenith, lifted the platform to rest the instrument’s weight, loosened the bolts, and tried to nudge MIRAC over. But we weren’t able to move it far enough to shift the pupil.

Rory and Manny loosening the MIRAC bolts.

At this point thick clouds had rolled in (quote of the day: “If you can no longer see the moon, it’s cloudy!” –Amali). We waited it out a while, but eventually called it a night around 4am.

Pyramid pupils, obscured by clouds.

Today was Rory’s birthday — Happy birthday Rory! We celebrated with cake(s).

The song of the night is Happy Birthday to You.

MAPS 2023A Day 3: MIRAC-5 has entered the chat

After some berating from @jlong, here is my inaugural post! First, an obligatory observatory picture.

The MMT at sunrise with the full moon on the horizon

The MIRAC-5 team arrived Friday, June 2nd to prepare for installation of the latest iteration of the instrument. Originally conceived in 1988 by Bill Hoffmann at the University of Arizona, MIRAC (Mid-Infrared Array Camera) is an ever-evolving mid-IR camera built for observing between 1 and 18 microns. It has a long and illustrious career of testing out mid-IR technologies, including various detectors and nulling interferometry (test bed for LBTI nulling). As the name suggests, we are on the 5th iteration after almost a 10-year dormancy period!

MIRAC was pulled out of retirement and refurbished to house a new mid-IR detector: the 2k x 2k GeoSnap-18 array manufactured by Teledyne. This GeoSnap is an engineering grade device with a wavelength cut-off of 13 microns. Designed for high-background applications this array is perfect for ground-based mid-IR astronomy! The primary features are wavelength sensitivity at H, K, L, M, and N-Bands (science-grade arrays will extend down to 0.7 microns), well depths of 1.3 million e– (twice that for science-grade), and continuous frame rates of >85 Hz without any reset or data acquisition overheads! After commissioning of MAPS and MIRAC, we plan to use these instruments to characterize exoplanet and brown dwarf atmospheres in the mid-IR, complementing the capabilities of JWST MIRI.

The GeoSnap engineering array in its storage contain. Of the full 2048 x 2048 pixels, only one quadrant is bonded with photosensitive material (HgCdTe).

Anyway, off came the PISCES camera and on went MIRAC. Comparatively, MIRAC is a bit of a beast.

U. Michigan graduate student Rory Bowens (right) and U. Arizona PI Jarron Leisenring (front left) and U. Michigan PI Michael Meyer (back left) posing next to MIRAC-5 mounted to the MAPS top box.

Upon hooking up the bazillion cables, we realized that the fiber extender used to transfer the data from the GeoSnap detector to the computer (located in an adjacent rack) wasn’t working as expected. The only solution was to keep the original (short) cables attached and strap the computer to the instrument cart on the telescope. It didn’t seem to complain about the free ride.

After bringing the detector temperature to a cool 40K, we were able to get the acquisition software working on the first try thanks to the diligent efforts of our software engineer Dennis Hart and successful implementation of the @jrmales’s rtimv visualization software.

Early image of a controlled PSF at K-Band running with a frame rate of 5 Hz. Hot pixels have not been masked out.

Throughout the evening, we successfully acquired a number of stars, co-aligned with MAPS, performing continuous PSF display at high frame rates, tested internal pupil chopping operations, measured background levels, and a whole host of other commissioning activities. While a few challenges inevitably arose, which we will address during the summer, it has been a pretty successful and rewarding “pre-commissioning” run so far!

Additional Random Photos

Sunset over Kitt Peak
MMT Primary
Michigan PI Michael Meyer

Song of the Day