Blog – Page 164 – Extreme Wavefront Control Lab

First MagAO arrivals

Alan, Jared, and Katie arrived today as the first of the MagAO commissioning team. We stopped at El Pino before heading up to the mountain. Here are Jared and Alan with the eponymous tree:

La Serena is a beautiful beach town, and we couldn’t decide whether it reminds us of San Diego, Santa Cruz, or San Francisco. You decide:

And here’s a picture for our various mothers and other followers who are fans of the many gorgeous flowers that are in bloom in late Spring in Chile:

Finally, we made it up to Las Campanas Observatory. We saw our old friend Vizzy. We also saw the sunset when we went up to visit our telescope, the 6.5-m Magellan Clay:

We went up and powered up all the motors and computers, and everything is working fine! Clio is cooled and doing great. Tomorrow we will attend the LCO turnover meeting, meet the staff, check up on our instruments and stages, and get prepped for the arrival of the PI.

Turno

Manny and Richard are on their way home. Clio2 survived shipping, and is ready for MagAO to send it some flat wavefronts.

it fits — The electronics rack for Clio2 fits, and doesn't vibrate (too much).

The last thing the guys did was train the LCO staff on how to keep Clio cold.

theory — Manny Montoya briefing the LCO crew on Clio2 operations.

practice — Some hands on training. The blue gloves keep your fingertips attached to your fingers - LN2 is cold!

The next MagAO detachment leaves Tucson today. We’re on our way.

Clio2 Gets The Freeze

After shipping, unpacking, and verifying that everything still works, the last step was for Manny and Richard to cool Clio2 down. Then they took some pictures.

awwww yeeeah. — Manny celebrates after taking a good, low-noise, pupil image. He and Richard just successfully cooled Clio2 down to operating temperature and confirmed that the detector works.

Since it works in the IR, basically detecting the heat of planets and brown dwarfs, Clio2 is kept very cold. This is because a blackbody at room-temperature emits most of its energy at a wavelength of about 10 μm, according to Wien’s law. A lot of flux from the tail of the distribution is also emitted at near-IR wavelengths of 1–5 μm. Therefore, for IR astronomy, it is important to keep the telescope and the instrument cold, to avoid this excess thermal flux, which shows up as noise in our images (you’ll hear us call it “sky” or “background”).

To make this work, Clio is contained in a dewar, which is a kind of vacuum flask (a.k.a. Thermos) — an insulated canister that keeps cryogenic material at very cold temperatures. Clio2 has a nested-dewar design with an outer and an inner vessel. The cryogen we use is liquid nitrogen, which has a boiling point of 77 K stp. We also lower the pressure in the inner dewar, using a vacuum pump, in order to solidify the nitrogen (55 K). A blackbody of 77 K emits most of its radiation at ~38 μm, and a blackbody of 55 K emits most of its radiation at ~53 μm. These wavelengths are well beyond what we care about when hunting planets.

In case you ever find yourself in charge at LCO, the cooldown steps and instructions for refilling cryogens are also posted in the Clio user manual.

Our Logo

With some help from Shannon Close, the Magellan AO project now has an official logo. Without further ado:

Vizzy Lives!

Richard caught a glimpse of the grumpy old man, one of the two Viscachas who live over the clean room. When last we saw them, they had just been caught breaking and entering the ASB to steal bananas, and the last update I got was “the problem has been dealt with”. I was worried! But the VisAO mascot appears safe, sound, and as grumpy as ever.