Tonight we sought refuge from the snow at the Ridge and then in Tucson.
Here’s what we woke up to:
Photo by Bianca. Image description: Telescopes at the ridge in heavy fog.Staying cozy in the ridge. Photo by Bianca. Image description: A view from inside of a window bay, a bit of a comfy recliner, and a cold cloudy day outside.
We had to clear the Bowl and Summit due to snow accumulation and possible ice. The Ridge was safe, but we also saw that we wouldn’t be opening tonight or tomorrow, and there aren’t enough rooms at the Ridge, so we decided to go down to Tucson. If the weather clears up we’ll go back up on Tuesday for our last night.
Weather tonight [Image description: Weather webpage snapshot showing: Temp 32*F, humidity 97%, wind gusts up to 55mph, clouds, and snow]
We didn’t open tonight due to thick clouds. The MIRAC team took a lot of darks and dome “skies” to assess their QE and background noise. It started snowing around 2am and we left the dome around 3:30 with snow already accumulating on the ground.
Animal of the day:
The animal of the night is the Torbie cat, a combination of Tabby + Tortoiseshell
It’s a MAPS/MIRAC run! The semester is still 2023B but the year is 2024 and we are back commissioning again, this time the 10 micron Geosnap-enabled instrument MIRAC. Tonight we spent a lot of time on alignment, as we have changed pretty much everything post-telescope, from the dichroic to the detector placement! Pointing and centering with non-linear tri-axial mounts on a cold night in the dome made us really appreciate the bright wintry touches:
A beautifully decorated fir tree [image description: pine tree with Christmas ornaments].Image description: The MMT atop a snowy peak.Image descriptoin: Sunset through the pines.
Here are some neat alignment tricks: And don’t forget the pupil imager lens!
A target on periscope fold mirror 1. [Image description: A bullseye on paper, held over a glass, as viewed through a digital camera.]Pyramid pupils with a bullseye. [Image description: 4 round images with the same bullseye as in the previous picture, off center and zoomed in, as viewed through a different digital camera.]
After alignment, we got some closed loop calibrations and have also been training new AO operators!
Tonight we had great weather: low winds, moderate humidity, good seeing (0.6”–0.8”), and spent the whole night from civil dusk to civil dawn on bright stars near zenith! We stuck with the IR WFS and did calibrations and noise measurements all night long. For example, here is a Hadamard Matrix measurement using CACAO to look at the inter-actuator stroke:
[Image description: CACAO GUIs showing pyramid pupils and weird spirally shapes commanded on the ASM.]
And here are the CACAO and ASM control screens:
[Image description: Pyramid pupils and ASM commands per actuator.]
And we got some PSFs with MIRAC (although we only got up to 30 modes closed so I don’t have a good AO-on/AO-off sequence), here are some nice L-band speckles:
[Image description: Speckly un-corrected PSF at L-band.]
We compared the latency measured with the visible WFS (top) and the IR WFS (bottom):
[Image description: Two scatter plots of latency tests.]
Video of the night: Inspired by all the animals we’ve seen at the MMT or the drive up here (jack rabbits, owls, grey foxes, skunks, and… baby coatis!), here is a video of coatis looking like brontosaurs if you run them backwards:
[Media description: YouTube video of coatis walking, video has been reversed, and the Jurassic Park Theme music is playing. They look like brontosaurs!]
Tonight felt a lot like whiplash, from tired to energized to tired to energized, from starry to humidity to starry, and from failure to fix to failure to fix!
First of all the MAPS daytime/nighttime/whenevertime support crew (Oli, Grant, Dan) drove up this afternoon with the repaired (by Ken) bias board for the CCID-75 LittleJoe controller, as well as the IR dichroic for the Saphira. Unfortunately once we plugged in the board, we were still unable to communicate over serial. Manny’s next guess is we may also have a problem with the power supply. So ultimately that will require more lab testing and repair. Instead, we’ll use our other WFS for the rest of the run.
Anyway, so it was time to get on sky. Here are all the good AO setup stars, as defined by searching Simbad for zenith-y and bright:
dec > 20 & dec < 50 & vmag < 2
Plus I added in Theta 1 Ori C for good measure(ments). (And actually Alpha Gem isn’t a good AO setup star, as it’s a binary with two very bright A stars only a few arcsec apart — but it’s zenith-y and bright.)
Airmass curves for the good (zenith-y and bright) AO setup stars, plus Theta 1 Ori C. [Image description: x-axis is time, y-axis is airmass and altitude. Stars are Alpha Lyr, Alpha Cyg, Alpha Per, Alpha Aur, Beta Aur, Beta Tau, Theta 1 Ori C, Alpha Gem, Beta Gem, and Eta UMa.]
Oli, Grant, and Dan then switched out dichroics and we moved to Deneb (aka Alpha Cyg) and they were about to complete the alignment when…
More humidity rolled in! Noooo! We were shut from about 9pm to 3:30am, and Oli and Grant became night crew too.
When it cleared up again, we got back on sky — this time on Beta Tau (real name: Elnath). We found it, aligned it, saved all the offsets — and tried to switch to a new star — and the offsets no longer worked! After some telescope dancing, we (Rory, Brian, me) realized we had the wrong units for our proper motion coordinates. Sigh. So I mostly* fixed that, and now we are off and running! [*I fixed the algebra but not the trig yet — just to do it as quickly as possible by hand — and the trig has only mattered once in my experience thus far, on Proxima Cen (which is apparently the highest-proper-motion star, with a large enough dec for the cosine to matter), that I’ve ever locked on.]
Here’s an IDL code snippet for future posterity:
;; Proper motions are given from Simbad in (Cartesian) mas/yr
ans = simbad_data(star) ;; Calls the function simbad_data.pro
;; Returns ans.pm_ra which is RA proper motion in mas/yr
;; And ans.pm_dec which is Dec proper motion in mas/yr
;; And ans.icrs_dec which is sexagesimal Declination which you have
;; to convert to decimal-degrees which is the variable DEdeg
;; Magellan wants RA in sec of time per year and Dec in arcsec per year.
pmra_mag = (ans.pm_ra / 1e3) * (24/360.) / cos(DEdeg*!pi/180.)
pmde_mag = ans.pm_dec / 1e3
;; MMT wants RA in sec of time per century and Dec in arcsec per century.
pmra_mmt = ans.pm_ra * 24/3600. / cos(DEdeg*!pi/180.)
pmde_mmt = ans.pm_dec / 10.
Right now Jared, Amali, and Lauren (and Andrew remotely) are taking AO calibrations with the Saphira IR WFS, and Rory is taking data with MIRAC. Oh BTW Lauren is our new team member as of this week, her first day was our first night on-sky, and she’s doing great!
[Image description: Jared, Amali, and Lauren at work on AO, sitting in front of their operator stations.][Image description: Rory working on MIRAC at its operator station, and Brian at the Telescope Operator station.]
[Image description: Background-subtracted MIRAC un-corrected PSF at L-band.][Image description: IR WFS pyramid pupils.][Image description: Acquisition camera un-corrected PSF in the visible.]
Anyway, after our 0 for 5 first night, it’s great to be working with 5/5 — (1) stars are visible, (2) telescope is allowed to open, (3) conditions are safe enough for ASM, (4) AO hardware is working, and (5) science camera is ready!
And… the loop is closed just as we passed into civil twilight from nautical (having gone well past astronomical twilight)! (This is why we always get the full-moon bright time, our tiny pixels and kHz framerates don’t care about background light except for the actual Sun itself.)
And now for The Video Of The Night… I forgot to bring my Pilates travel equipment, but I can do a little bit of a workout just rotating my myofascia in spirals like in this video by my Pilates coach, “Spirals on the Cadillac for MyoFascia Release” by Arlene Corcoran:
Spirals on the Cadillac for MyoFascia Release by Arlene Corcoran
