Instrument Status

Current Announcements

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: Starting in November of 2024, additional non-gaussian noise has been present on the detectors. As of late-October 2025 the read noise on the Green side remains elevated (~10 electrons), while the red side is at our target level (~4.3 electrons).
  • LFC: Initial evaluations of the reliability of the LFC after the recent service look promising, though the bluest flux (below ~490 nm) is not consistent.
  • Detector Cooling Systems: The green side CCR has very little overhead on maintaining temperature and has quasi-periodic deviations which affect the detector. Red side is performing well, but has shown evidence of a slow degradation of performance.
  • Etalon: Operational.
  • Detector Errors: The red and green detectors suffer from occasional “start state errors” in which the affected detector does not produce a useful exposure. The observing scripts detect this, abort the exposure (with read out) and start a fresh exposure on both cameras. No action is necessary on the part of the observer. The occurrence rate is such that around one in every 180 exposures is affected by one of the two detectors experiencing this error.
  • Ca H&K Detector: The CA H&K detector is operational.
  • Exposure Meter Terminated Exposures: Operational.
  • Tip Tilt Corrections: The tip tilt axis are currently correcting as expected.
  • Double Star Observations: Operational.
  • Simultaneous Calibration (SimulCal): Simultaneous calibrations are supported.
  • Off Target Guiding: Not yet commissioned. Currently, the tip tilt system must be able to detect the science target in order to position it on the fiber.

Last Updated: 2026-02-01

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 Date & Time (HST) Delta T
G 2025-11-09 21:22:50 7 mK
G 2025-11-10 05:48:42 109 mK
G 2025-11-10 13:15:18 2,825 mK
G 2025-11-15 11:50:50 250 mK
G 2025-11-16 16:04:50 5,779 mK
G 2025-11-17 09:17:54 5,564 mK
G 2025-11-17 10:34:40 6,147 mK
G 2025-11-17 11:52:54 87 mK
G 2025-11-18 05:06:38 4,200 mK
G 2025-11-19 01:01:22 5,862 mK
G 2025-11-19 02:15:06 90 mK
G 2026-01-23 21:28:10 95 mK
G 2026-01-25 16:15:50 712 mK
G 2026-01-30 19:52:12 129 mK

Past Announcements