A method of measuring object shapes (i.e., fitting those shapes to ellipses). These moments are close to optimal for measuring the shapes of faint galaxies, and have been used for weak lensing studies. See the Adaptive Moments section of the algorithms pages.

A philanthropic nonprofit institution (www.sloan.org) established in 1934 by Alfred Pritchard Sloan, Jr., then President and Chief Executive Officer of the General Motors Corporation. An early award from the Sloan Foundation was recognized by naming the survey the Sloan Digital Sky Survey. The Sloan Foundation has continued to be a major supporter [..]

Target observed as part of an APOGEE ancillary program to utilize the survey’s capabilities for interesting science beyond its primary survey goals. The target flags associated with APOGEE ancillary programs are part of the APOGEE_TARGET1 bitmask. The ancillary programs are described in the APOGEE Ancillary Targets pages.

Spectroscopic target selection in BOSS is dominated by two categories: LRGs, and quasars. However, a small fraction of the fibers are devoted to a variety of additional projects, ranging from studies of variable stars to host galaxies of supernovae. These additional targets are referred to as BOSS Ancillary Targets. A full list of the target flags [..]

A neural network technique for selecting quasars for spectroscopy in the BOSS survey. It is one of the techniques used in the BONUS quasar sample. The algorithm is described in Yèche et al. 2010.

Apache Point Observatory, located in Sunspot, New Mexico. This is the location of the 2.5m SDSS telescope as well as the Photometric Telescope (PT), as well as other non-SDSS telescopes, such as the ARC 3.5m telescope. See the APO homepage.

The Apache Point Observatory Galactic Evolution Experiment, one of four surveys included in SDSS-III. This is using a high-resolution (R~22,500) H-band spectrograph fed by 300 fibers. The spectrograph saw first light in 2011, and the survey will observe roughly 100,000 stars, mostly in the disk of the Milky Way, to obtain detailed chemical composit [..]

The software pipeline used by APOGEE to calculate basic stellar parameters (Teff, log(g), [Fe/H], [α/H]) and other elemental abundances (Garcia Pérez et al., in prep.). The pipeline is described in the ASPCAP pages of the Infrared Spectra documentation.

Astrophysical Research Consortium. Incorporated in the State of Washington. Members include the University of Washington; New Mexico State University; The University of Chicago, Princeton University; Johns Hopkins University; the University of Virginia; the University of Colorado; the Institute for Advanced Study. Body that owns and operates APO.

Magnitudes within SDSS-I/II are expressed as inverse hyperbolic sine (or “asinh”) magnitudes, sometimes referred to informally as luptitudes. The transformation from linear flux measurements to asinh magnitudes is designed to be virtually identical to the standard astronomical magnitude at high signal-to-noise ratio, but to switch over to linear be [..]