Special Plates

Extra Deep Plates

A few BOSS plates have been observed multiple times with different pluggings, or observed with the same plugging to greater depth (summed signal-to-noise squared) than typical:

Observed to ~3x median depth:
- Plate 3683 MJD 55178, 55245
- Plate 3879 MJD 55244
- Plate 4083 MJD 55441, 55443
- Plate 4202 MJD 55445
- Plate 5141 MJD 55746
- Plate 5399 MJD 55956
Observed to ~7x median depth split over 3 pluggings:
- Plate 6037 MJD 56074, 56104, 56106
Multi-epoch Stripe 82 commissioning plates for LOWZ, CMASS, and QSO samples, also going to greater depth than typical. These two plates cover the exact same targets on the same sky location:
- Plate 3615 MJDs 55856, 55445, 55208, 55179
- Plate 3647 MJDs 55945, 55827, 55476, 55241, 55181

Ancillary Program Plates

There are also several plates which were dedicated mostly to particular ancillary programs. These are:

Emission Line Galaxies / Luminous Blue Galaxies: plates 5017, 5018
QSO variability selection in Stripe 82: plates 5141 - 5147
Mostly sky fibers for sky subtraction tests: plate 5745

Notes

In all cases, the plates are processed identially to standard survey plates and all targets treated the same.
See the BOSS_TARGET1, ANCILLARY_TARGET1, and ANCILLARY_TARGET2 bits for details of which targets come from which programs and details about those programs.
Also note that there are many other ancillary program targets interleaved with the rest of the survey on standard BOSS plates as identified by their ANCILLARY_TARGET1 and ANCILLARY_TARGET2 bits. The above plates simply point out a few cases where most of a plate is dedicated to ancillary programs.