SDSS-III: Four Surveys Executed Simultaneously

SDSS-III consists of four surveys executed on the same 2.5m telescope: the Apache Point Observatory Galactic Evolution Experiment (APOGEE) the Baryon Oscillation Spectroscopic Survey (BOSS), the Multi-Object APO Radial Velocity Exoplanet Large-area Survey (MARVELS), and the Sloan Extension for Galactic Understanding and Exploration 2 (SEGUE-2).

BOSS focuses on mapping the Universe on the largest scales, creating the largest volume three-dimensional map of galaxies ever created. SEGUE-2 and APOGEE focus on the structure and evolution of our own Milky Way galaxy. MARVELS searches very nearby stars for evidence of "exoplanets" surrounding them.

The BOSS and SEGUE-2 programs require "dark" time when the Moon is less than 60% illuminated, or below the horizon. The APOGEE and MARVELS programs are executed during the remaining "bright" time.

High-level SDSS-III schedule. Dark-time observing programs are marked in orange, bright-time observing programs marked in green.

The MARVELS and BOSS spectroscopic surveys begin in 2008 and 2009, and APOGEE begins in 2011. SDSS-III will be busy taking data through the summer of 2014. Our projected schedule for future public data releases over that time period is as follows:

Date	Data Release	APOGEE	BOSS	MARVELS	SEGUE-2
2011 Jan	DR8		Final imaging		Final spectra
2012 Jul	DR9		Spectra (up to 2011 Jul)
2013 Jul	DR10	Spectra (up to 2012 Jul)	Spectra (up to 2012 Jul)
2014 Dec	DR11	Spectra (up to 2013 Jul)	Spectra (up to 2013 May)
2014 Dec	DR12	Final spectra	Final spectra	Final radial velocities

Why are DR11 and DR12 being released simultaneously? DR11 will be a packaging of all the data up until mid-2013, necessary to validate that season's data. In order to preserve that data and make it possible for others to reproduce DR11 results, we will publicly release DR11 at the same time as DR12.