Author: Katie Morzinski

Making giant telescope mirrors

MagAO and VisAO got a lot of press last week, when we announced our first-light results — demonstrating diffraction-limited imaging with 0.02 arcsecond resolution. This is the finest resolution of any filled-aperture long-exposure images ever taken! See the press release here.

But did we ever tell you where the Magellan telescope primary mirrors come from?

Steward Observatory Mirror Lab at the University of Arizona

They come from the Steward Observatory Mirror Lab (SOML) and it is the only facility in the world making giant self-supporting monolithic mirrors. Testing and polishing is also done right here in the facility. At the SOML the techniques were researched, developed, and executed by a team led by Roger Angel (who was awarded the Kavli Prize for his work). All of our beautiful images coming out of MagAO and VisAO would not be possible if the telescope mirror wasn’t producing an amazingly flat wavefront. The primary mirror must be stiff and strong, but also quickly responsive to changing temperatures for maximum stability. This is accomplished by an innovative hollow honey-comb structure for the glass mold that is both strong and lightweight. The glass is melted in a 2000-deg.(F) furnace spinning at 5 rpm to produce the proper shape, before being polished to a perfection of 20 nm rms.

Bear Down.

This past Saturday was the casting of the GMT3. The Giant Magellan Telescope (GMT), not to be confused with the Somewhat-Less-Giant Magellan Telescope, is a 25-m-diameter telescope being built for use at Las Companans Observatory in Chile. The GMT will be on a neighboring peak to our own at LCO. Once we get tired of MagAO/VisAO images (lol), GMT will be one of the next telescopes producing the highest-resolution images ever!

A model of the Giant Magellan Telescope

GMT3 is the third off-axis segment for the GMT. The first and second segments have been cast, and this past weekend marked the melting and beginning of the cooldown of the glass for the third segment. Here are some pictures and videos we took at the event. For the official stuff go here.

Here is the third segment, GMT3. It is spinning at 5 rpm in a 2000-deg. furnace to melt the glass.

And here’re some videos of the action, showing the spinning oven:

The first two segments have already been cast and are stored in the mirror lab:

The first segment of the telescope, called GMT1, cast in 2005. It is now complete, with a better than 20 nm RMS surface polish.

The second segment, GMT2, was cast in 2012. This is its backside, which was first smoothed to prepare for mounting in its cell. It will soon be flipped, and polishing will begin on the front optical surface.

And here is the fourth segment… we’re halfway there!

The fourth segment, GMT4, is in pieces here.

The participants in the casting event were members of the GMT consortium and their guests

The mirror lab is hard at work on other projects too, 24/7. During the tour the LSST primary mirror was being polished:

This is the large polishing machine, where the LSST is spinning around while the stress lap polishes it to perfection.

Peter Strittmatter explains the spin-casting process.
This is the test tower used to measure the wavefront of the mirror blanks during polishing. There at the top, that’s me! You can see my name tag reflecting off the 3-m spherical mirror used to test the mirrors — I was standing in the right place on the floor.
Roger Angel shows off his new furnace, for fabricating solar-telescope mirrors.

MagAO at PPVI: Are you the ones with the visible-light disk?

MagAO is representing at the Protostars and Planets VI conference this week in Heidelberg, Germany. Wie geht’s? Well, so far it’s been an inspiring week, seeing all the strides forward our field has come in understanding how stars and planets form, and their physical and chemical properties, since the last Protostars and Planets (PPV) conference seven years ago. You can follow the latest at Twitter.

Our beautiful PSFs and first-light results have resulted in many questions about how to observe with MagAO. Interested observers should please check out Information for Observers and look for collaborators at the Magellan institutions: Arizona, Carnegie, Michigan, Harvard, MIT, and Chile.

One of our favorite comments so far was when I was meeting another astronomer, and mentioned MagAO/VisAO, and he said, “Are you the ones with the visible-light disk?” This is referring to the beautiful I-band image we have on Jared’s poster of a famous debris disk, of which we captured a gorgeous picture.

Oh and speaking of pictures, did everyone wave at Saturn tonight? At 21:27-21:42UT Cassini was taking a picture of Earth, and we were enjoying a picnic dinner along the Neckarwiese (the park by the Neckar River), so we stood where we could see Saturn and waved. We’re in the Cassini picture!

Here are pictures from the conference this week:

How it all began.
The Schloss at night.
Kate Follette and Keven Flaherty discuss Kate’s poster.
Ilaria Pascucci, a professor in LPL, gave a talk on photo evaporation in disks.
Arizona grad Mary Anne Peters, a former student of Laird who is now working on her PhD at Princeton, showed us her poster on tidally heated exomoons.
Nathan Smith has a cool poster here.
The Heidelberg Schloss dominates the hill side above the town.
Colette Salyk, NOAO Goldberg Fellow, gave a great talk on volatiles in disks.
Megan Reiter explains her poster to an interested PPVIer.
Arizona grad students Brian Svoboda and Youngmin Seo.
The conference reception was at the Schloss. Here’s your MagAO sunset from Heidelberg.
Jason Dittmann, another UA Astronomy + Laird Grad (now at Harvard working on his PhD) shows off his poster.
UA LPL alumn Jonathan Fortney. Yes, that is the Death Star.
MagAO’s own Derek Kopon and his poster — which isn’t even on MagAO!

Quote of the week: “If I’m choking, you all have permission to touch my belly” — Kate Follette.

Runner-up quote: “Is your laptop the Milky Way?” — Chabrier, response to theorist with a dissenting simulation.

MagAO is back in Tucson

MagAO is back in town. We have returned from our conferences in Florence (AO4ELT) and/or Victoria (IAU 299 exoplanets) to get down to serious work on our papers we presented at the conferences, and our plans for the next year. Our talks and posters went over well, and we got a lot of requests about how to get MagAO observing time. Institutes that share Magellan telescope time are the Carnegie Institution of Washington, Harvard University, MIT, the University of Michigan, and the University of Arizona. Check with your collaborators at those institutes and keep an eye on this blog to find out about plans for the next MagAO observing run.

Some of our observing partners also presented MagAO results at the IAU symposium. Here are our Arizona State University friends Jenny Patience, Rob De Rosa, and Kimberly Ward-Duong posing by Kim’s poster:

Kim Ward-Duong and Jenny Patience of ASU, standing by Kim’s poster about a direct imaging study to search for and characterize planetary mass companions.
Kim Ward-Duong and Rob De Rosa of ASU.
Johanna Teske of the UA discusses her poster about the role of oxygen abundances in exoplanet host star C/O ratios: a case study of 55 Cnc

We also saw Emily Rauscher there, the first Sagan Fellow at the University of Arizona:

Emily Rauscher stands by her poster about Uneven cooling: The influence of atmospheric dynamics on the thermal evolution of gas giants

We took a few other pictures of our friends’ and collaborators’ posters but they got corrupted. Anyway, we hope you enjoyed those tidbits of the conference.

Finally, here’s a great picture of Jared and Alfio from the AO4ELT conference, in the place that started it all:

Jared and Alfio posing on the Arno in Firenze, with the Ponte Vecchio in the background.

Speaking of MagAO’s software engineers, somehow this hasn’t yet gotten posted to the blog, but Alfio modified some code last run so that we can save and watch the turbulence in real-time as it blows across the ASM. Here it is, it’s really cool to watch!

Dans les Nouvelles / In the News

MagAO teammates and friends Jared Males, Andy Skemer, and Laird Close recently published a paper: Direct Imaging in the Habitable Zone and the Problem of Orbital Motion. This work describes the problem of how planets won’t hold still, but instead keep orbiting their stars while you’re trying to observe them. The paper is in proof with the Astrophysical Journal Supplements.

The paper, including the implications for VisAO, drew the attention of Canadien journalist Claude Lafleur, who penned the following article: Un jour prochain, nous photographierons des planètes habitables. Check it out, especially if you read French!

And if you’re going to be in Florence for the AO4ELT conference, or in Victoria for the IAU 299 conference, we look forward to seeing you there and presenting our first-light results!

Comm2 Day 21: All packed up

Today Laird, Jared, and I packed everything up in preparation for departing… and possibly not coming back for almost a year.

Jared was in charge of backing up all of our computers and archiving the VisAO data. We have 5 computers on the mountain: The WFS supervisor, the ASM supervisor, the VisAO supervisor, the VisAO camera computer, and the Clio camera computer. It’s a good thing he knows what he’s doing.

Jared starts up a bunch of jobs to back-up the computers and archive the data. Nice hard hat.

Laird and I supervised the ASM’s journey from the top of the mountain to the clean room in the ASB. This always makes me a little nervous. We had to wait until the afternoon to do it, because in the morning there were winds up to 33 mph, a bit too windy for shipping around such delicate equipment. But it went very well and the ASM is now safely in the clean room.

We bring the ASM down from the telescopes to the Astronomer Support Building where the clean room is.
The ASM backing up to the ASB.
The P.I. supervises closely.

Laird and Dave attached the new dust covers to the NAS.

Jared and I did an inventory of our supplies so that we can remember what we need to re-stock next time.

I said goodbye to Vizzy.

When I was walking down from the mountain tonight after doing a last sweep, I walked in the dark, and my eyes got adapted so that I could see my shadow by the crescent moon, and more and more stars appeared. The Magellanic Clouds really pop down here too.

OK, this picture of Enrico and Alfio under the stars is by Enrico from
Nov. 25th Comm1, but I also didn’t have any good night-time pictures (with my cell phone).