Google Sky labs
The labs below make astronomy more accessible to students by introducing the subject through the Sky layer of Google Earth. Sky is automatically included in Google Earth, and can be accessed by clicking on the Saturn Icon at the top of the application window, or by going to View->Sky in the drop-down menu.
The Sky layer can be supplemented by user-generated plugins written in a simple markup language called KML. The plugins add interactive features, images, and call scripts that query external databases, like the Sloan Digital Sky Survey (SDSS), so that students can easily engage research grade data.
To load a given plugin the user should start Google Earth, load Sky and then go to File->Open in the drop-down menu and browse for the file. Most plugins are only activated when the viewport stops so, after loading, you have to pan and stop again before the plugin will become active.
- SDSS Galaxy or Star Query Plugin -- Based on Simon Krughoff's SDSS plugin, it queries for galaxies or stars in the field of view from the SDSS spectroscopic and photometric database, circles them and provides information in a pop-up window, including a link to spectrum if available.
(Note: the Galaxy Spectrum Query in the "Galaxy Query Plugin" is currently set to return spectra for all objects in the SDSS because object identification is unreliable. From the image context it is usually clear what the spectrum pertrains to.)
- SDSS Galaxy Color-Magnitude or Stellar HR Diagram Plugin -- Queries galaxies in the field of view from the SDSS database and displays their color-magnitude diagram.
Note: popup and circled galaxies are from the Query plugin graph in left is from the HR/CMD plugins .
*Labs were assembled by Sam Leitner in collaboration with Andrey Kravtsov and Mike Gladders.
|Introduction to Google Sky
||Basics of Sky: The surveys included and a quick reference.
|The HR Diagram
||Stellar Populations: Explore the HR Diagram of Open Clusters, Dwarf Spheroidals, and Globular Clusters in the SDSS, and of field stars in Hipparchos.
|SDSS Star Query, SDSS Stellar HR Diagram, Hipparcos Star Query and Hipparcos-HR (thanks to James Stafford). Locations: Open Clusters, Dwarf Spheroidals, and Globular Clusters.
| Morphological Types, Spectra of Galaxies, and the Hubble Expansion Law
||Constructing the Hubble Diagram: Measure distance from Brightest Cluster Galaxy photometry, and redshifts from galaxy spectrum.
Homogeneity of Space: Show that Galaxy counts are a Poisson distribution on large enough scales.*NOTE, scales listed in the lab are currently actually too small to see Poisson statistics.
Understanding Spectra: Explore the general shape of spectra for various morphological types.
|SDSS Galaxy Query w/o redshifts displayed.
Locations: BCGs and random fields
|Galaxy environments, clusters of galaxies, and dark matter
||Galaxy Environments: Field galaxies, cluster properties and cluster finding
|SDSS Galaxy Query and Galaxy Color-Magnitude Diagram.
Locations: Clusters, Groups, and Fields (same fields as hubble lab),
Documentation for developers
- This repository contains scripts that generate KML plugins via SQL queries to SDSS
- The following GET request queries SDSS for objects within the SDSS footprint: http:///query-gal-hr.pl?BBOX=-33.05,25.00,-33.00,25.05
To debug output in a specific region use "west,south,east,north" position arguments that Sky passes to scripts -- these correspond to the Declination (Dec) and the Right Ascension (RA) minus 180 degrees.
- Check that your KML is strictly compliant. KML can be interpretted properly in Sky, but still be unstable to upgrades.
- KML tutorial for Google Earth
- Sky layer examples
These efforts are funded by the University of Chicago and the Kavli Institute for Cosmological Physics.