Mask bits for an SDSS spectrum

Each of these bits is set for each fiber and each pixel. 0-15 indicate something about the fiber; 16-31 indicate something about that particular pixel.

Bit name	Binary digit	Description
NOPLUG	0	Fiber not listed in plugmap file
BADTRACE	1	Bad trace from routine TRACE320CRUDE
BADFLAT	2	Low counts in fiberflat
BADARC	3	Bad arc solution
MANYBADCOLUMNS	4	More than 10% of pixels are bad columns
MANYREJECTED	5	More than 10% of pixels are rejected in extraction
LARGESHIFT	6	Large spatial shift between flat and object position
BADSKYFIBER	7	Sky fiber shows extreme residuals
NEARWHOPPER	8	DEPRECATED, no longer set for BOSS DR9. Prior to DR9 meant within 2 fibers of a whopping fiber (exclusive)
WHOPPER	9	Whopping fiber, with a very bright source.
SMEARIMAGE	10	DEPRECATED. Prior to DR9 meant smear available for red and blue cameras
SMEARHIGHSN	11	DEPRECATED. Prior to DR9 meant S/N sufficient for full smear fit
SMEARMEDSN	12	DEPRECATED. Prior to DR9 meant S/N only sufficient for scaled median fit
NEARBADPIXEL	16	Bad pixel within 3 pixels of trace.
LOWFLAT	17	Flat field less than 0.5
FULLREJECT	18	Pixel fully rejected in extraction (INVVAR=0)
PARTIALREJECT	19	Some pixels rejected in extraction
SCATTEREDLIGHT	20	Scattered light significant
CROSSTALK	21	Cross-talk significant
NOSKY	22	Sky level unknown at this wavelength (INVVAR=0)
BRIGHTSKY	23	Sky level > flux + 10(flux_err) AND sky > 1.25 median(sky,99 pixels)
NODATA	24	DEPRECATED. May be set, but should be ignored in favor of flagging on INVVAR=0 instead. Prior to dr9 meant no data available in combine B-spline (INVVAR=0).
COMBINEREJ	25	Rejected in combine B-spline
BADFLUXFACTOR	26	Low flux-calibration or flux-correction factor
BADSKYCHI	27	Relative χ² > 3 in sky residuals at this wavelength
REDMONSTER	28	Contiguous region of bad χ² in sky residuals (with threshold of relative χ² > 3).