KPF Eras
Significant changes to the Keck Planet Finder instrument are designated by increments of the KPFERA keyword. Each value of KPFERA spans a date range. Half integer values (e.g., 1.5) are meant to be periods of engineering work while integer values (e.g., 1.0) are meant to be “science eras” during which the instrument is stable. Smaller instrument changes are indicated by 0.1 increments indicate smaller instrument changes (e.g., 2.6 vs. 2.5).
The table below displays the contents of the file static/kpfera_definitions.csv in this repository, which defines the time period of KPF eras and has notes about the instrument changes betweent them.
Users should expect offsets between the RV times series of a given source between half-integer and larger increments of KPFERA (e.g., 1.0 -> 1.5). The offset will not be the same for every star due to differences in spectral content as a function of wavelength. Thus, it is unlikely that a prescription for offests can be determined at high RV precision. A future version of this page will quantify differences between RVs in KPF eras.
KPFERA |
UT_start_date |
UT_end_date |
comment |
|---|---|---|---|
0.5 |
2000-01-01 00:00:00 |
2022-11-09 00:00:00 |
Before First Light (engineering) |
1.0 |
2022-11-09 00:00:01 |
2024-02-03 00:00:00 |
First science era: First Light to Service Mission #1 |
1.5 |
2024-02-03 00:00:01 |
2024-02-11 00:00:00 |
Service Mission #1 (SM1 - engineering). SM1 tasks included: focus adjustment of Green camera; Reformatter adjustment to equalize SCI1 and SCI3 slices; Wide Flat fiber alignment. |
2.0 |
2024-02-23 12:00:01 |
2024-11-01 00:00:00 |
Second science era: after Service Mission #1 |
2.5 |
2024-11-01 12:00:01 |
2025-01-01 00:00:00 |
Service Mission #2 (SM2 - engineering) which extended into on-sky science observations because of quasi-fixed pattern noise. SM2 tasks included: installation of closed-cycle refridgerator (CCR) on Green cryostat (replacing LN2-based cooling); installation of thermal enclosure. |
2.6 |
2025-01-01 12:00:01 |
2025-03-28 23:00:00 |
After a full Green-side warmup after a closed-cycle cooler pressure issue |
2.7 |
2025-03-28 23:00:01 |
2025-04-23 00:22:00 |
Service Mission #3 (SM3 - engineering). SM3 tasks included: installation of closed-cycle refridgerator on Red cryostat (replacing LN2-based cooling); extensive testing of the electical environment to assess and mitigate quasi-fixed pattern noise. The Green CCR continued to show signs of intermittent and reduced cooling capacity. |
3.0 |
2025-04-23 00:22:01 |
2025-08-29 20:30:00 |
Third science era: after Service Mission #3 with quasi-fixed pattern noise reduced but still elevated at ~12 electons per CCD pixel. |
3.5 |
2025-08-29 20:30:01 |
2025-10-30 00:00:00 |
Service Mission #4 (SM4 - engineering). SM4 tasks included: leak found and fixed in the Green CCR plumbing; extensive measurements and cable rerouting to eliminate apparent read noise (partially successful); installed final heaters/sensors in enclosure; installed precision wedged filters in cal system. |
4.0 |
2025-10-30 00:00:01 |
2040-01-01 00:00:00 |
After SM4 and a full Green-side warmup to recharge the Green CCR with refrigerant (a week post-SM4) |