Keck Differential Trackng Rates and Limiting Magnitudes
ARC
Last updated 24mar2008

L G S

Method
Limiting Magnitude
Limiting Rate
Comment
On-axis; with open-loop-tracking = sidereal Science Target must be brighter than 18Vmag. Approx. 20 arcsec/hour Common
On-axis; with open-loop-tracking = 'correct' Science Target must be brighter than 18Vmag. Approx. 4 arcsec/second. Theoretical; never tested.
Offset (e.g., appulse) Science Target can be very faint; appulse must be brighter than 18Vmag. Approx. 20 arsec/hour Tested very recently; available as shared risk only.


N G S

Method
Limiting Magnitude
Limiting Rate
Comment
On-axis; with open-loop-tracking = sidereal Science Target must be brighter than 15Vmag. Approx. 20 arcsec/hour Common
On-axis; with open-loop-tracking = 'correct' Science Target must be brighter than 15Vmag. Approx. 4 arcsec/second. Proven (e.g., XP14 [Busch, et al]), but not commonly used.
Offset (e.g., appulse)
Not Possible!