Known Issues

For issues relevant to DECaLS imaging, consult the DR5 issues page.

Repeat Sources Due to Check-pointing

The legacypipe code applied a series of check-points in case of failures during processing. Unfortunately, when the code resumed after a check-point failure, it sometimes produced a duplicate of the same source. These duplicates can be identified because they have identical coordinates and fluxes but a different OBJID. An example repeated source is here:

https://www.legacysurvey.org/viewer-dev?ra=215.8471&dec=0.0805&zoom=16&layer=decals-dr5&sources-dr5&bricks

This source has the following attributes in catalog-level DR5 data:

Attribute	Source 1	Source 2
`RA`	215.84766	215.84766
`DEC`	0.080533681	0.080533681
`BRICKID`	331231	331231
`OBJID`	4938	4941
`TYPE`	DEV	DEV
`FLUX_G`	5.86150	5.86150
`FLUX_R`	22.1008	22.1008
`FLUX_Z`	47.8499	47.8499
`FLUX_W1`	28.0480	28.0480

(i.e. fluxes and coordinates are identical but OBJID is different).

In DR6, we estimate that there are many thousands of duplicates spread across 264 bricks. The full list of DR6 bricks that contain duplicates, and the number of duplicates in each brick, is available here.

One brick was processed with a different pipeline version

Brick 1228p810 was processed with a different stack of codes, as detailed at the bottom of the description page.