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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).