MagAO Commissioning Day 1: Left-Handed Vulture Droppings

We had an exciting day on the MagAO project here at Las Campanas Observatory.  There were bugs, birds, left-handed translations, a handoff, some solidified N2, and the sun got a little fainter too.

Today was the crew changeover.  See Katies’s post about how the next Turno was shown the workings of Clio’s dewar and LN2 refilling procedure.

The big excitement for the day was the solar eclipse.  See this post for more on MagAO’s first on-sky results.

We got a little done on the NAS today too.  Alan did a bunch of guider testing, and has declared victory. Jared and Katie tested the bayside stage motors, our very powerful X-Y-Z translation motors which move the entire W-Unit to align and focus.  These weren’t tested last night since we like to be careful and make sure we don’t destroy the project (as a general rule).  We tested their movement in 3 axes to verify that everything works smoothly and that no hoses or cables are pinched.  Now, in optics the Z-axis is traditionally along the optical axis, and positive in the direction of motion of photons.  Katie noticed that our X and Y axes then follow the “left-hand rule” for their coordinates, and was inspired to pose for a picture.  This is Katie’s way of saying, politely, that we do things a little backwards at Arizona.

Katie demonstrates the "left-hand rule" for the coordinate system of the X, Y, Z Bayside stages.

After getting the stages up and running, we could then align the system.  This means using the stages to get our artificial star on the optical axis of the W-unit.  With a pyramid AO system, we always feel good when we get a nice set of 4 round pupil images.

Our pyramid wavefront sensor pupils at left, and the VisAO spot on the left.
Here Jared is showing some relief that everything turned back on.

There have been a few animal sightings.  She’s the only one on the project to date, but Katie has seen a bunch of bugs.  It is spring, so maybe they are coming out.  We also saw a turkey vulture circling the summit.  Nobody got a good pic, but there was unambiguous evidence of its passage.

Our various mothers are going to be disappointed.

Quotes of the Day:
While discussing VisAO’s tiny field of view:
Matt Walker: “it would take a long time to do a sky survey with an 8 arcsecond field of view”
Alan Uomoto: “well, that depends, do you want to do it at 20 milliarcseconds?”
(good comeback Alan)

Tyson Hare: “Look how easy it is to entertain a room full of nerds.”  (during the eclipse)

After the eclipse, we were treated to yet one more amazing LCO sunset.

The Magellan 6.5m telescopes at sunset. Clay at left, Baade on the right.

Clio handover

Tuesdays are when LCO staff swap shifts.  A meeting is held with all technical staff, who share information in order for the handover to go smoothly.  This afternoon, the instrument staff who are keeping Clio cool met to show each other how it works.

Clio handover 1
Clio handover 1 - Victor Meriño, Mauricio Navarrete, Alan Uomoto, and Gabriel Martin
Clio handover 2
Clio handover 2 - Mauricio Navarrete, Jorge Bravo, Gabriel Martin, and Alan Uomoto
Clio handover 3
Clio handover 3 - Victor Meriño, Jorge Bravo, Gabriel Martin, Emilio Cerda, and Mauricio Navarrete


Clio handover 4
Clio handover 4 - Gabriel Martin, Jorge Bravo, Mauricio Navarrete, and Alan Uomoto

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:

El Pino
El Pino

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:

La Serena
La Serena

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:

Spring flowers
Spring flowers

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:

Katie at Clay
Katie at 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.

Clio, 2012/11/12
Clio, 2012/11/12


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

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.

Manny Montoya briefing the LCO crew on Clio2 operations.
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.

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.