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July 2013  •  Volume 6 Number 2

Computing the Cosmos: Hands-on with Google Compute Engine

Simon Krughoff, astronomer at the University of Washington presents at Google I/O

The LSST software stack had a leading role at this year’s Google I/O, an annual conference for developers featuring the latest tools and techniques from Google’s product teams and partners. Simon Krughoff, astronomer at the University of Washington and member of the LSST Data Management and Image Simulation teams, co-presented a session with Google’s Jonathan Simon on using the LSST software stack to search for previously unseen objects in the Sloan Digital Sky Survey (SDSS).

This particular session, a “codelab”, used Google’s compute engine to create co-added images that contain faint optical counterparts to objects detected by the Wide-field Infrared Survey Explorer (WISE) survey. The technique was to find sources in the WISE catalog that have no nearby match in the SDSS. For each unmatched WISE source, images from the SDSS “Stripe 82” (a region that was repeatedly scanned by SDSS over a period of about 10 years) that overlap with the WISE pointing were identified. The SDSS images were then warped and aligned to produce a co-added image of the relevant part of the sky in three bands and to generate a color image. This co-added color image was then examined to search for optical counterparts to the WISE survey detection.

The 200+ developers who participated, more than expected, learned how to get started using the Google Compute Engine by first installing software and setting up a firewall. Then participants went through the steps of using Compute Engine instances for stacking and aligning individual SDSS images with the LSST software stack. In the two hour session the students were able to process color postage stamps for more than 3000 WISE targets. The LSST software stack was exercised strenuously in this codelab and held up well. Krughoff comments ” it was very nice to see how easy the stack was to install and run. It was also really nice to see that the LSST primitives are at a place where we can do a relatively complicated task with relatively few lines of code.”

There was a lot of excitement in the room as people realized that they might be the first to look at this part of the sky. The results of participants’ work were combined to create a gallery of images of outer space containing numerous astronomical objects, some potentially new counterparts to the WISE infrared detections.

Krughoff plans to participate in Google IO next year as this experience allows the LSST software to be tested and used under strenuous conditions. It is too early to tell if any new discoveries were made but the LSST code did well while being used by a large number of highly talented and motivated young software professionals, the future developers and perhaps users of LSST!

Article written by Suzanne Jacoby, Simon Krughoff, and Andy Connolly


LSST is a public-private partnership. Funding for design and development activity comes from the National Science Foundation, private donations, grants to universities, and in-kind support at Department of Energy laboratories and other LSSTC Institutional Members:

Adler Planetarium; Argonne National Laboratory; Brookhaven National Laboratory (BNL); California Institute of Technology; Carnegie Mellon University; Chile; Cornell University; Drexel University; Fermi National Accelerator Laboratory; George Mason University; Google, Inc.; Harvard-Smithsonian Center for Astrophysics; Institut de Physique Nucleaire et de Physique des Particules (IN2P3); Johns Hopkins University; Kavli Institute for Particle Astrophysics and Cosmology (KIPAC) – Stanford University; Las Cumbres Observatory Global Telescope Network, Inc.; Lawrence Livermore National Laboratory (LLNL); Los Alamos National Laboratory (LANL); National Optical Astronomy Observatory; National Radio Astronomy Observatory; Princeton University; Purdue University; Research Corporation for Science Advancement; Rutgers University; SLAC National Accelerator Laboratory; Space Telescope Science Institute; Texas A & M University; The Institute of Physics of the Academy of Sciences of the Czech Republic; The Pennsylvania State University; The University of Arizona; University of California at Davis; University of California at Irvine; University of Illinois at Urbana-Champaign; University of Michigan; University of Pennsylvania; University of Pittsburgh; University of Washington; Vanderbilt and Fisk Universities

LSST E-News Team:

  • Suzanne Jacoby (Editor-in-Chief)
  • Robert McKercher (Staff Writer)
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  • Sidney Wolff (Editorial Consultant)
  • Additional contributors as noted

LSST E-News is a free email publication of the Large Synoptic Survey Telescope Project. It is for informational purposes only, and the information is subject to change without notice.

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