These pages describe in detail how SDSS performs target selection. We focus here on target selection for the MOS (multi-object spectroscopy) programs, which observe with the optical BOSS and/or infrared APOGEE spectrographs. This covers the Black Hole Mapper (BHM), Milky Way Mapper (MWM) and open fiber programs.
We begin with an overview of the targeting process, including how targets are grouped in cartons with similar observing requirements. Details on the catalogs used for target selection are given in the cross-match page and sdss_id pages. We provide links to the documentation of MWM targeting, BHM targeting, open fiber targets, as well as sky and standard calibrators. We document how we track through the numerous target cartons with a set of targeting flags. Finally, we describe the fiber assignment process for plates (fibers plugged into aluminum plates, used until 2021) and the FPS (robotic fiber positioning, begun in 2022).
The integral-field spectroscopy target selection for the LVM-Instrument used by Local Volume Mapper (LVM) is a separate process. Their targeting process is described on the LVM targeting and observing strategy.