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Secondary target mask bits in SDSS-I, -II

These bitmask values are appropriate for the following bitmasks used for SDSS-I and -II: LEGACY_TARGET2, SPECIAL_TARGET2 or SECTARGET.

Bit name Binary digit Description
LIGHT_TRAP 0 hole drilled for bright star, to avoid scattered light
REDDEN_STD 1 reddening standard star
TEST_TARGET 2 a test target
QA 3 quality assurance target
SKY 4 sky target
SPECTROPHOTO_STD 5 spectrophotometry standard (typically an F-star)
GUIDE_STAR 6 guide star hole
BUNDLE_HOLE 7 fiber bundle hole
QUALITY_HOLE 8 hole drilled for plate shop quality measurements
HOT_STD 9 hot standard star
SOUTHERN_SURVEY 31 a segue or southern survey target