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 data releases over that time period is as follows:

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

Why is there no DR11 public release? DR11 will be an internal release of all the data up until July 2013, necessary to validate that season's data. If we were to release DR11 to the public, it would be in July 2014, almost immediately before the final release. Instead, we will only publicly release the final DR12.