This page documents some of the main updates to the Legacy Surveys since Data Release 9.
Gaia quantities included in files and catalogs are now drawn from Gaia EDR3.
Note, though, that the astrometric solution for DR10 was still calculated using positions and proper motions from Gaia DR2.
MASKBITSbitmask is now 32-bit rather than 16-bit, as a new bit called
SUB_BLOBwas added. This bit is described on the DR10 bitmasks page under MASKBITS.
CCD_CUTSbitmask is now 64-bit rather than 32-bit, as two new bits called
DEPTH_CUT_2were added. These bits are described on the DR10 bitmasks page under CCD_CUTS.
The Tractor catalogs contain a new per-band quantity called
xis one of \(g\), \(r\), \(i\) or \(z\). These quantities record the number of good (unmasked) images that contribute to a source in a particular band at a particular pixel-location. Prior to DR9, only
nobs_x(the total number of images that contributed to a source in each band) were recorded in the Tractor catalogs, which created an inconsistency with the "nexp" pixel-maps in the image stacks (which only record the number of good images). So,
ngood_xis recorded to allow a direct mapping between the number of good images in the Tractor catalogs and image stacks.
As an example of the difference, for saturated sources one would expect
ngood_xand the "nexp" pixel maps to be zero, but
nobs_xto correspond to the total number of exposures that contributed to the source.
The addition of
ngood_xfixes a known issue from DR9.