The South Pole Telescope

Tom Crawford — Mon, 11 Feb 2008 11:12:00 +0000

Back on the sky!

As of February 6, the new and improved SPT receiver is installed in the telescope and looking into the heavens. The last 10 days or so until South Pole Station closes for the winter are being spent characterizing the new array, focusing the telescope, and (this one is really important) making sure our 2008 winterovers Keith and Dana are prepared to run this beast and deal with any situations that might arise. Once these tasks are completed, we will settle into a stable observing routine for the winter season.

As a teaser, here's an image made from one of our regular observations of a galactic HII source:

SPT — Sat, 19 Jan 2008 08:21:00 +0000

We're famous! Final Webcast of the season, the Press and RSS

We had our final Exploratorium webcast yesterday, January 18th. The show is archived on their website in case you missed it. In other exciting news, the Chicago Tribune recently ran a story on the SPT. It was amazing seeing familar faces and photos from the pole splashed across the front page! For those of you not residing in Chicago, the article can be found here. Finally, we added RSS to the blog (thanks to our readers for the suggestion).

SPT — Fri, 28 Dec 2007 19:44:00 +0000

Check us out today on NPR!

Talk of the Nation will be doing a piece on the South Pole Telescope this afternoon. Tune in and listen or check their website after 6 (EST) today for the piece.

SPT — Thu, 20 Dec 2007 04:05:00 +0000

Upcoming Live Webcast: Dec. 21 2007

Be sure to visit the Exploratorium's website for another live webcast from pole on Dec. 21, 2007 at 8 am CST.

SPT — Thu, 06 Dec 2007 20:46:00 +0000

Live SPT-Exploratorium Webcast Tomorrow! (Dec 7th)

Be sure to head on over to the Exploratorium's site tomorrow at 9:00 CST to join us for a live webcast with members of the SPT team at pole. This is a great opportunity to ask SPT scientists questions about their research.

The last few weeks at pole we have been busy characterizing our detectors (Kathryn talks about her work on this here), preparing our receiver for an upgrade and improving the surface of our primary mirror. On the primary mirror, we hope to achieve a surface smoothness of 20 microns (less than the thickness of a human hair), which is quite an accomplishment across a 10 meter dish! Back in the states, we have been busy fabricating and testing new pixels for the camera this season. Here is a (seasonably appropriate) photo of one of new bolometers magnified 500x under a scanning electron microscope (SEM). Click here or here for more information on our detectors. For more on the SEM check out these links (background, gallery).

SPT — Mon, 15 Oct 2007 20:36:00 +0000

It has been a while since we last posted but that doesn't mean we haven't been busy. We just finished observing for this season and it was a success! Since deployment lots of exciting things have taken place. The SPT winter-overs, Zak Staniszewski and Steve Padin, have been living at the South Pole running the telescope. Since the SPT detectors operate at very low temperatures, the winter-overs spent part of each day cooling the detectors and setting them. Then, when the telescope is ready to observe, they use a computer to command the telescope to point at the regions of the sky that the collaboration decided to observe this Austral Winter. Each day the data is sent back to the SPT collaboration via satellite and the analysis team sets to work processing the raw data. One of the main goals of the analysis at this stage is to understand how each element of the instrument is working. The telescope is a very complicated instrument and before we are ready to use this data for science, we want to be really sure we understand how everything is working, especially the hundreds of individual detectors making up the camera. The next step in the analysis is to write a complicated set of computer programs that take raw data and process it into maps of the sky. We will be working hard over the coming months to prepare these maps and study them. Besides the analysis, there is a flurry of activity as we work to create an updated receiver to install on the telescope during the coming Austral Summer. Already, the first few members of the collaboration are headed back down to the pole to begin this season's work on the telescope

Below are some great pictures of the telescope during the Austral Winter taken by Zak Staniszewski and Steve Padin.

The telescope after a storm.

The aurora, a phenomenon seen most commonly at the poles of the earth caused by the interaction of the solar winds and the particles in the earth's magnetosphere.

The moon shining brightly behind the telescope.

The sunrise after a long dark winter. Since the earth's axis of rotation is tilted with respect to the light coming from the sun it is always dark for part of the year at South Pole and always light the other part of the year. For this reason, the sunrise is a very special event.

The white snow and telescope looking beautiful as the rising sun reflects off them.

SPT — Wed, 02 May 2007 17:18:00 +0000

The Long Goodbye

Now that the busy polar summer season is over, things have gotten much quieter around here. Although there are just two SPT team members (Zak Staniszewski and Steve Padin) left at pole, there is still tons of work to do! Right now we are busy commissioning the telescope, and thus far everything is progressing well. Here is a shot of the SPT scanning during these early tests:

Be sure to go check out the newly revised SPT Multimedia page where we've uploaded lots of movies and photos from both the test build in the US and construction at pole this season.

Kathryn Schaffer (Miknaitis) — Fri, 02 Feb 2007 16:50:00 +0000

Now that February is here, the temperatures at the South Pole Station have begun to drop again, and the station is preparing to close for the winter. Most of the people currently working at the station will fly out within the next couple of weeks, leaving only a core group of "winterovers" here who will stay through the extremely cold and dark months of the Antarctic winter.

The University of Chicago "reflector assembly team", consisting of Tom, Jeff, Joaquin and Ryan, has already left the ice. But many members of the SPT project are still here until the very end of the summer season to work on the receiver, the last few details of the telescope itself, and the software used to control the telescope and interpret the data that we take with it. At the moment, we are busy cooling down the receiver and the secondary optics in order to test how everything works when we put it all together. It's a very busy time, with people working around the clock.

Even though we all tend to be very focused on whatever tasks are currently at hand, everyone in the team finds themselves sometimes just staring at this beautiful telescope and admiring everything that has already been achieved this year. It really is a gorgeous instrument, and it's especially impressive to see how smoothly it moves. From the windows of the indoor laboratories where most of our work is taking place, we can see the last remaining crews who are working on the telescope outside in the cold. To assemble this enormous telescope has taken teams of iron workers, electricians, insulation workers, carpenters, and many other specialists here at the Station and back in the U.S. It's been incredible to be here and see how the whole South Pole Station is pushing for the success of this project.

Before the Chicago reflector assembly team left, we had a chance to take some pictures of them together with the iron workers and telescope specialists who played big roles in the construction of the telescope. Many of these individuals went through the process of test-building the telescope in Texas last summer, and here they are at the completion of the final instrument in one of the harshest places on earth. It's truly a great group of people and they've done an amazing job. All of the rest of us are in awe!

Tom Crawford — Tue, 23 Jan 2007 18:44:00 +0000

The Gang's All Here!

(Photo credit: John Kovac with Adrian's camera. Click here for a higher-res version.)

For a brief couple of weeks, we have assembled the entire SPT 2006-2007 South Pole Science team --- i.e., every scientist on the SPT project that's coming down this year. As you can see, we're quite a crew:

Lying down: Steve Padin

Kneeling (left to right): Tom Crawford, Kathryn Miknaitis, Tom Plagge, Matt Dobbs, Ryan Keisler

Standing, 1st row (left to right): Ken Aird, Zak Staniszewski, John Carlstrom, Joaquin Vieira, Martin Lueker, Erik Leitch, Jeff McMahon, Adrian Lee

Standing, back row (left to right): Clem Pryke, Steve Meyer, Brad Benson, Bill Holzapfel

Looming, background: The SPT

Tom Crawford — Thu, 11 Jan 2007 20:18:00 +0000

The Receiver Has Arrived.

The final (and possibly most complex) piece of the great puzzle that is the South Pole Telescope has arrived: The receiver. This is the end of the line for the light gathered by the telescope. Those ancient photons will end their existence being absorbed as heat onto the web of one of the ~1000 ultra-cold (1/2 degree above absolute zero) detectors, sensed as tiny temperature fluctuations by the tiny superconducting thermometer attached to the detector's web, and read out by the SQUID (superconducting quantum interference device) current meter / amplifier coupled to the detector. Computer records of these tiny temperature fluctuations will allow us to reconstruct the small-scale brightness pattern of the Cosmic Microwave Background (CMB) with unprecedented sensitivity, eventually enabling us (we hope) to measure the abundance of distant galaxy clusters through the distortion they imprint on the CMB and use this measurement to constrain properties of Dark Energy.

So we're pretty excited to have the receiver here. And already together and about to undergo some pre-installments tests. Amazing as it may sound (at least, it sounds amazing to me), the crew of newly arrived SPT scientists working on the receiver managed to unpack the receiver, open it down to its guts, install the detectors, close the receiver back up, and get it on the vacuum pump and cooling down within about 48 hours of its (and their) arrival.

(Speaking of which, we should note that we are now about a three times larger group of scientists than we were a few short days ago. Just arrived are: the receiver team of Bill Holzapfel, Adrian Lee, Brad Benson, Martin Lueker, and Tom Plagge (all from UC Berkeley) and Zak Staniszewski (from Case Western); Steve Meyer from Chicago (providing yet more receiver-type expertise and general wisdom); and software mavens Ken Aird and Kathryn Miknaitis from Chicago and Erik Leitch from JPL.)

Assuming that the receiver tests go well, we will be in position to couple it to the cryostat that contains the secondary mirror (which has also arrived at Pole but has not been unpacked and installed yet). And if that goes well, then it's onto the telescope with both of them, and we're off.

That's getting a bit ahead of things, but it's easy to get carried away when things are this exciting. For now, here are some pictures of the receiver and its contents.
(Thanks to Ryan for the pix.)

Adrian Lee working on the receiver focal plane (six wedges of 160 detectors each).

The fully assembled receiver on the pump and cooling down.

Tom Crawford — Fri, 05 Jan 2007 16:14:00 +0000

The Reflector Is Up.

As promised, the reflector has been placed on the telescope. This is one of the major milestones on the path to first light. It was a complicated two-crane lift (three if you count the one carrying people up to bolt the reflector down), and it was managed beautifully by Raytheon's Eric Nichols and Bill Johnson. As you can see from the mini-gallery below, it went off without a hitch, and we now have a darned impressive looking telescope --- just some testing and a camera away from mapping the sky.

The lift begins.

Docking the flying saucer.

Steve P., Joaquin, and Tim Hughes prepare to enter the belly of the beast (to attach the reflector center hub to the telescope).

As Bill Johnson and Aaron Thompson look on, the last of Steve disappears into the maw.

Ryan, Jeff, and I look on as the crane gently lowers the reflector into just the right place. (Photo credit: Jerry Marty)

The reflector in place, Eric Nichols and Brian Hardin fasten up the bolts that Bill and Aaron can't reach.

The telescope, facing the horizon (grid south), seen from the roof of DSL.

The telescope, facing the horizon (grid east), seen from the roof of DSL.

Tom Crawford — Tue, 02 Jan 2007 18:21:00 +0000

Tomorrow, we look like a telescope.

Sorry about the long delay between posts. The Christmas and New Year's holidays have taken up most of our free time, but there has been lots of work going on as well. The most exciting news is that after our first round of photogrammetry, analysis by Jeff, and tweaking of the mirror panel positions, the surface of the mirror looks to be within a tenth of a millimeter of bang on, and the path looks clear to getting it significantly better than that. Since then, the mirror has been lifted off the large invar cone that will attach it to the telescope, and the invar cone itself has been lifted and attached to the telescope. And tonight, when the mirror and back-up structure get lifted and attached, we'll have a telescope that looks darn near complete.

Then comes the minor detail of something at the telescope focus to detect the incoming light. Two cryostats and 10 scientists show up later in the week to start that process. Stay tuned.

Tom Crawford — Fri, 22 Dec 2006 17:49:00 +0000

All the Panels are on the reflector!

(The following is simply a transcription of Jeff's e-mail to the collaboration announcing this milestone.)

Hi all,

Last night we placed the last panel on the bus, and here is the
picture to prove it. The dish may look flat, but that is just the
fish eye undoing its curvature- every indication is that it is very
close to the correct shape. Just wanted to send out a picture so
you can share in our enthusiasm.

-Jeff

ps. The sun dog picture is from right after we finished.

The (almost) fully populated reflector

Auspicious omens in the sky on the occasion of the placement of panel #218

Tom Crawford — Sat, 16 Dec 2006 20:16:00 +0000

The Telescope & Reflector Begin to Take Shape

A quick disclaimer before today's post: The SPT is not just the primary mirror, and the collaboration does not consist solely of the reflector assembly team. It may seem that way at the moment (at least to readers of this blog), but that will change rapidly as more members of the team --- and more pieces of the instrument --- show up at the Pole. January will bring lots of new faces and much more emphasis on the receiver (i.e., the part of the telescope that actually detects and records the incoming light). But for now, you're going to keep hearing about the telescope infrastructure and the primary mirror.

OK, now back to the post.

Though it may seem slow, the progress on the telescope infrastructure and primary mirror continues --- pretty much on schedule even. A couple of days ago, the first piece of the telescope lower boom (the structure that extends out from the primary mirror and holds the secondary and receiver) went into place, giving the first hint of the scale and final shape of the telescope.

Telescope with part of lower boom

Meanwhile, the reflector assembly folks have spent the last few days in furious panel-placing and -aligning mode. In fact, we're up to a pace of over 20 panels a day placed and aligned to (we hope) less than 100 microns. If we can keep this up, we'll have all the panels placed a few days before Christmas, at which point we spend a couple of days taking care of some wiring and mechanical details, then it's on to testing the surface. The first big test of how well we managed to align the surface will use a technique called photogrammetry. I'll defer a detailed explanation of this process to a later post; for now, it suffices to know that one takes a bunch of pictures with a specially outfitted camera then hands those pictures to an incredibly expensive piece of software that picks out the locations of hundreds of little reflective targets stuck to the mirror surface (and some bigger targets too) and uses that information to determine the exact shape of the mirror surface. You can see the photogrammetry targets (and the progress we've made laying panels) in the picture below. In this photo, Steve P. is using a feeler gauge (a precision set of metal shims) to check the job that Jeff, Ryan, and I did on the latest set of panels. The large metal bars layed across the middle of the reflector are to give the photogrammetry software a known length scale to work with, the foam pads with pressboard on top allow us to walk across the panels, and the shrouded piece of equipment in the center of the reflector is a theodolite (a surveying instrument we use in panel alignment).

Steve checks the alignment job.

Tom Crawford — Tue, 05 Dec 2006 17:20:00 +0000

Panel Alignment

As of last post, we had assembled the reflector backup structure (BUS) and were ready to start placing reflector panels. The first step was to get the BUS from where we assembled it (next to the airstrip, right where the pieces came out of the LC130 they arrived in) to where the rest of the telescope was going together --- namely the Dark Sector Lab (DSL), about 1km from the South Pole Station. We had assembled it on a sled just for this purpose.

The BUS on the move

At DSL, the BUS was dragged into a large tent built to shelter us from the wind as we worked, and we could begin the prep work needed to place panels. This work mostly fell to Jeff, who is in charge of understanding how one makes an off-axis paraboloid by placing 218 irregular shapes at different heights above an on-axis paraboloid. (If "off-axis" and "on-axis" mean nothing to you, just believe me that this is a crazy idea.) After lots of thinking on Jeff's part and some manual labor by the rest of us, we had seven panels placed in the innermost ring.

Prep work on the BUS inside the tent

Perhaps not surprisingly, how things looked after this initial placement resulted in lots more brainwork by Jeff (with a little help from the rest of us), sniffing out small non-idealities in certain parts of the system that have to be taken into account for everything to fit correctly. After a few iterations of this, panel placement can now begin in earnest.

Ryan Keisler — Wed, 29 Nov 2006 20:10:00 +0000

Just a heads up: although he is several days behind in his publishing, Ryan has been adding posts, photos, and videos to his blog.

Tom Crawford — Tue, 28 Nov 2006 15:43:00 +0000

The BUS is together.

As of late Tuesday night, the reflector back-up structure (BUS) is fully assembled, shimmed to its proper alignment, torqued up and ready to go. Panels start going on tomorrow. Exciting stuff...

The mostly completed BUS:

Tom Crawford — Fri, 24 Nov 2006 21:09:00 +0000

Hello, South Pole!

The boys of the Reflector Assembly Team have arrived at the South Pole, and are, well, assembling the reflector. Some first impressions of life at the bottom of the world can be found on Tom's blog here.

And don't forget the live webcast tomorrow, Saturday November 25 at 12PM Central time. Catch it at www.exploratorium.edu/poles/telescope.php.

Tom Crawford — Fri, 24 Nov 2006 21:04:00 +0000

The Reflector Assembly Team (RAT) --- i.e. Jeff, Joaquin, Ryan, and Tom, i.e. the only people who are blogging right now --- have reached the continent of Antarctica.

Read fascinating tales of safety lectures, airplane rides, and 104-year-old seals at Tom's blog here.

And don't miss the first of four South Pole webcasts hosted by the Exploratorium (San Francisco's science museum and our partners in education and outreach) this Saturday, November 25 at 12PM Central Time. The webcast can be found at the Exploratorium's Polar Science website: www.exploratorium.edu/poles/.

Ryan Keisler — Sun, 19 Nov 2006 05:05:00 +0000

The trip to the South Pole is not a short thing. For me it began in Chicago about 2 days ago, on Thursday November 16, as I boarded a plane (with coworkers Tom and Jeff) headed to LA. There we met up with fellow graduate student Joaquin and took a 12-hour overnight flight to Auckland, New Zealand. In crossing the International Date Line during this flight I was completely robbed of the day Friday, November 17, 2006. Next up was a short flight to Christchurch, New Zealand, where I write this post.

Our time in Christchurch has been very nice so far. We've had a little time to walk around town and check out some cafes and restaurants (very impressive food so far), and last night we were even fortunate enough to experience the city's nightlife scene. Today Joaquin and I took a walk through the city's well known botanical garden (I'll post some photos when I have a better internet connection). The main purpose of our stay in Christchurch was taken care of this afternoon when we were assigned the 40-odd articles of extreme weather clothing which keep us warm and functional when we work outside at the South Pole.

Anyway, we have a few more hours to enjoy Christchurch before our "zero six hundred hours" appearance at the military airport tomorrow morning. Then we all pile into this noisy plane and fly to Antarctica. Should be fun.

Tom Crawford — Sun, 19 Nov 2006 04:38:00 +0000

Jeff, Tom, Ryan, and Joaquin are halfway there.

Well, more than half geographically and less than half psychologically. We have arrived in Christchurch, New Zealand and are scheduled to fly to McMurdo Station tomorrow, then on to the Pole the next day.

More details on Tom's page here.

Jeff is snapping pictures like a madman, and we'll post a bunch when he gets them downloaded.

SPT — Wed, 25 Oct 2006 03:06:00 +0000

Welcome to the South Pole Telescope group blog!