Ancillary Targets
The APOGEE-2, eBOSS, and MaNGA surveys support ancillary programs. The SDSS-III component surveys APOGEE-1 and BOSS also had ancillary programs that are still accessible though the buttons below.
What are ancillary targets?
The SDSS's spectroscopic plates observe many spectra at once (from 600 to 1,000 per plate, depending on the survey), all in a single area of sky (a circle of sky about 3 degrees in diameter). The surveys' primary targeting programs do not always have enough target density to fill up an entire plate. To maximize the efficiency of the entire SDSS, we put out a call for proposals for ancillary target programs, resulting in all plates being filled to capacity.
Ancillary targets are divided into programs, each of which has its own scientific rationale and target selection criteria. You can select targets from any of the ancillary programs by searching for bitmask values in the appropriate data fields.
SDSS ancillary target documentation is organized by survey. Click on one of the survey buttons above to see its ancillary target programs.
