Instrument Status

Current Announcements

KPF is OFFLINE until further notice due to the vacuum pump failure described in the 2026 April announcement above. A Failure Review Board is investigating the root cause of the pump failure and will advise the Observatory on a path forward. Until that report comes out, the schedule for KPF's return to service is uncertain.

Status Summary by Subsystem

This is an attempt to summarize the status of various sub-systems of the instrument. Each sub-system name is color coded to indicate the status at a glance: green means functioning normally, orange means mostly normal, but with some caveats or minor issues, and red means the sub-system is compromised in some way.

  • Detector Noise:
  • LFC:
  • Detector Cooling Systems:
  • Etalon:
  • Detector Errors:
  • Ca H&K Detector:
  • Exposure Meter Terminated Exposures:
  • Tip Tilt Corrections:
  • Double Star Observations:
  • Simultaneous Calibration (SimulCal):
  • Off Target Guiding:

Last Updated: 2026-04-10

KPF Era 4.0 Temperature Stability Summary

KPF Era 4.0 began in late-October 2025 after Servicing Mission 4. We continue to have issues with the cooling systems for the detectors, especially the Green side. We list below all temperature excursions in which one of the detectors deviated temperature by more than 5 mK from the set point. Excursions of order 1 K (1000 mK) or more are expected to induce a radial velocity offset which is not calibratable. We are providing this data as a guide, but users should not assume that past performance is a good indicator of future performance -- we have seen indications that the cooling systems are slowly degrading, so an increasing rate of these temperature excursions is a distinct possibility.

Side Duration Delta T Start (HST) End (HST)
Green 0.05 hours 7 mK 2025-11-09 21:22:14 2025-11-09 21:25:06
Green 0.36 hours 109 mK 2025-11-10 05:37:12 2025-11-10 05:58:50
Green 2.78 hours 2,825 mK 2025-11-10 11:09:06 2025-11-10 13:55:54
Green 0.63 hours 250 mK 2025-11-15 11:28:36 2025-11-15 12:06:32
Green 2.54 hours 5,779 mK 2025-11-16 14:27:20 2025-11-16 16:59:54
Green 4.04 hours 6,147 mK 2025-11-17 07:52:06 2025-11-17 11:54:40
Green 2.31 hours 4,200 mK 2025-11-18 03:40:28 2025-11-18 05:59:16
Green 3.14 hours 5,862 mK 2025-11-18 23:08:20 2025-11-19 02:16:52
Green 0.56 hours 95 mK 2026-01-23 21:12:46 2026-01-23 21:46:16
Green 1.20 hours 712 mK 2026-01-25 15:25:34 2026-01-25 16:37:48
Green 0.46 hours 129 mK 2026-01-30 19:36:24 2026-01-30 20:03:54
Green 13.82 hours 53,527 mK 2026-02-17 21:17:12 2026-02-18 11:06:40
Green 4.48 hours 11,585 mK 2026-02-19 02:40:56 2026-02-19 07:09:32

Past Announcements