Data YOU can use

Are you intrigued by finding cool stuff in data?  Well, you are in luck!  Many astronomical data sets are public.  You can download them yourself, and analyze the data to your heart’s content.

Data sets to get started:

  • Sloan Digital Sky Survey: A revolutionary sky survey of the northern hemisphere.  I’d recommend starting with the imaging survey, where you can download data taken with different optical filters.  The astronomical data standard is the FITS file format.  One awesome thing about Sloan is that the data are pretty user-friendly–for many applications, the data are ready to go, and you don’t need to do the hard work of data reduction and calibration.  Please see their how-to guides, linked above.  If you just want to “mouse around” for fun, you can enter astronomical coordinates or objects of your choice in the SkyServer.  Find something cool-looking?  Hit the “Quick Look” button and learn more about any Sloan data product or measurement available on the object.  Note that the Legacy Survey sky viewer is another fun “mousing” opportunity, with way more surveys folded in (including the Dark Energy Survey in the southern hemisphere).
  • For the ultimate in NASA space data, check out the Mikulski Archive for Space Telescopes (MAST).  Search by coordinates or name, and find a treasure trove of UV to infrared data, including from the Hubble Space telescope.
  • Pan-STARRS is another deep optical northern hemisphere survey.  It has a strong time-domain component, and is useful for locating variable stars nearby (extremely useful for distances!) as well as tiny galaxies outside the Sloan footprint.
  • Data from our LBT-SONG telescope, the LBT, are archived for public use.  Note that some significant data reduction may be required on your end for your application.
  • Our Canadian friends at the CADC maintain a server for CFHT data, among other products.  My collaborator and fellow “data raccoon” Scott Carlsten (currently a grad student at Princeton) mined the archive for this nice search for satellites of nearby galaxies.
  • Are you interested in seeing how stars vary with time in the night sky?  My colleagues Chris Kochanek and Kris Stanek have you covered with their ASAS-SN Sky Patrol.  Type in coordinates, see how your favorite object has changed (or not) in the past X days.

There are a ton of other public data sets and data search portals, the ones listed above are the places that are easiest to get started if you want to get started playing with optical data.  See this page for a comprehensive list of data servers and products.

Analysis tools:

  • The first thing I want to do when I get some data is to look at it.  There are a number of astronomical image viewers, but probably the one used most often in the optical world is ds9.  Why yes, there was a TNG.  Why do you ask? You can download the version of ds9 appropriate to your computer, and get cracking!
  • Are you a fan of python?  Good!  I strongly recommend the Anaconda distribution for many reasons, one of which is that it comes with the premier astronomical data analysis distribution, astropy.  It just…works.  Astropy is a community-driven effort, and I love that they have very helpful tutorials you can use to learn from, and to use as the basis for your own new fun analyses.
  • We wrote this set of notes and project (galaxies_aspire) for the ASPIRE physics summer camp for high school girls founded and run by my OSU colleague Prof. Amy Connolly.  You too can rediscover the nearby dwarf galaxy Cetus using data you can download from the Sloan Digital Sky Survey.  This activity is based on one our group had previously run at the Ohio Supercomputer Center Summer Institute for high school students.  The amazing Dr. Johnny P. Greco created an additional activity for ASPIRE based on image processing and galaxy hunting.  Two messages.  First, if you are in high school in Ohio, please consider applying to these summer programs!  Second, you can download the pptx notes and get started yourself.  I will update them at some point in the near future with clearer instructions and more fun things to try.  These summer programs were funded in part by our NSF grants.
  • For galaxy searches, we frequently use the Source-Extractor code.  Basically, this is an automated way to see if a bunch of pixels have flux above the background on some spatial scale.  It’s the automated version of the smoothing functions we walk you through in the pptx slides described in the previous bullet point.  Note: the older versions are easier to install on a Mac than the newest version.

Want to know more?  Your search engine is your friend.