Sunshine and Big Mirrors

Blue skies and citrus

Tucson in January: Blue skies and citrus

Last week I got back from a great work-pleasure jaunt to the United States. I started off in Tucson, Arizona, where I met with the MIRI test and calibration team to further our plans for space domination instrument testing, calibration and software development for our instrument, which will be launched on board the James Webb Space Telescope in 2018. I’ve been involved in testing MIRI for my entire postdoc career now and it’s always a pleasure to meet with the team, and see how far we’ve come in the project.

Many people ask me what there is left or us to do, now that MIRI is in the hands of NASA in the US. The answer to that is “LOTS”. Even though the immediate task of assembling and testing the actual instrument hardware is completed, we now have to work with our NASA colleagues to integrate MIRI further with the rest of the spacecraft and test over and over again that everything is still in working order. In addition, we have to define calibration procedures and the data and algorithms that are required for that, and develop software. There’s an awful lot of work still happening!

Aside from the productive meeting I was really pleased to get a tour of the Steward Mirror Lab, which I’d heard lots about. Several of the world’s largest astronomical mirrors were cast and polished in giant spinning ovens, deep in the bowels of the University of Arizona’s football stadium . In these ovens, heat melts the glass until it’s molten, and the rotation shapes it into a nice parabolic shape while it’s in that state. The temperature is then lowered very slowly in a controlled way to stop stresses and bubbles forming in the glass. The mirror is shaped around a honeycomb structure that is later removed, producing a nice lightweight mirror.

With this technology Steward produced the mirrors for the 3.5-m mirrors for the ARC at Apache Point, New Mexico, and the WIYN at Kitt Peak, AZ; the 6.5-m’s for Magellan in Chile and for MMT at Mt. Hopkins, AZ; and the twin 8.4-m mirrors for the Large Binocular Telescope at Mt. Graham, also in Arizona.

Excitingly, several large mirrors are currently in production there at the moment. The first two 8-m segments for the Giant Magellan Telescope have been produced, and a third is under way. The primary mirror for the Large Synoptic Survey Telescope (LSST) was being polished while I was there. This mirror is pretty amazing, as it contains both the blanks for the primary and the tertiary mirror, so two different profiles are being polished into it. I’ve included some pictures below [feel free to use them but please credit to me when you do!].

 

Steward Mirror Lab

Steward Mirror Lab

Arizona stadium

Arizona stadium

Arizona stadium, home of the Steward Mirror Lab.

Arizona stadium, home of the Steward Mirror Lab.

The LSST primary and tertiary mirrors, being polished.

The LSST primary and tertiary mirrors, being polished.

The polishing tool working its way around

The polishing tool working its way around

Preparing for another GMT mirror segment

Preparing for another GMT mirror segment

Modelling comets, kittens and the Universe

Some images returned by the Comet Holmes Yahoo! query (Lang & Hogg, 2011)

 

This post was chosen as an Editor's Selection for ResearchBlogging.orgSome call it the data deluge, others the Fourth Paradigm – whatever your phrase of choice, it’s undeniable that science is increasingly driven by the easy availability of large amounts of data. The web is instrumental in their dissemination around the world. Web service providers such as Amazon enable storage of and access to data in the cloud. Continuing our progress in the exploration of the natural world depends ever more crucially on our ability to curate data and extract information from it.

On the last day of .Astronomy, David Hogg gave a talk on the paper he posted with collaborator Dustin Lang to astro-ph last week. In the paper Lang & Hogg describe how they reconstructed the orbit of Comet 17P/Holmes, which was prominently visible in the night sky in 2007, from images posted to the web by amateur photographers. After performing a Yahoo! image search and sorting out the relevant pictures, they ran their image set through the Astronomy.net system. Astrometry.net, created by Lang, cleverly attempts to calculate an astrometric calibration of astronomical images that contain no positional information, by fitting the positions of stars to known asterisms.

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AstroInformatics I: From Data to Knowledge

Optical layout of LSST, the catalyst for many semantic headaches

Like many sciences, astronomy is becoming increasingly data-rich. The next generation of observatories, such as the Large Synoptic Survey Telescope, will produce staggering amounts of data every night and push the subject into the petabyte regime. The large surveys that feed a substantial portion of the research community today, such as the Sloan Digital Sky Survey, are already demonstrating the difficulties of converting large datasets into knowledge: converting the data into catalogues, estimating selection biases and performing robust statistics are all common problems to those working with the data. Astroinformatics, or the science behind the information captured in our wealth of astronomical data, is therefore becoming an increasingly relevant field of study. The AstroInformatics 2010 conference was organised with the aim of essentially defining this emerging field.

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