Apache Point Observatory
New Mexico, USA
ARC 3.5-m Instrument News
Note: Comments in bold are to catch the readers attention as the most relevant for their upcoming science observations
News Worthy Items
- ARCES is available. See below for more information.
- ARCTIC is available. See below for more information.
- KOSMOS is available. See below for more information.
- NICFPS is available. See below for more information.
- Triplespec is available. See below for more information.
Current Status
Instrument issues which our users should be aware of before taking data. For historical information go here. For future instrumentation or planned upgrades go here.
ARCES
- NOTE (2022): Most recent interorder ratio plot can be found here.
- NOTE (2025): The DATE-OBS timestamp in the headers have been incorrect since sometime on or after 2024-08-27. The time was off by approximately +45 minutes from the start of the exposure. The timestamps are now correct as of last week 2025-09-22. ThAr lamp has some weak but not missing lines. At this time we suspect it is a manufacturing problem with the pressure of the argon gas in the HCL but we are investigating further.
- 2026-01-26: The instrument IOL is excellent.
- 2026-01-19: The instrument IOL is excellent.
- 2026-01-12: The instrument IOL is excellent.
- 2026-01-05: The instrument IOL is excellent.
- 2026-01-12: The instrument IOL is excellent.
ARCTIC
- NOTE (2025): Please consult with the Observing Specialist if you wish to take dome/cover flats with ARCTIC. With the supplemental baffle there is a flat field that is dependant on telescope position (altitude) and rotator angle that should be taken into account when taking flats.
- NOTE (2025): Bias levels are showing a slow creep, please take biases close in time to science data and compare overscans to be sure.
- 2026-01-26: The instrument is performing nominally, Minus Diffuser Rotator. Instrument serviced over past two weeks Cryotiger two year service complete. Optics cleaned. Optics have defects that may apear in images but should flat field out.
- 2026-01-19: The instrument is performing nominally, Minus Diffuser Rotator. Down for service.
- 2026-01-12: The instrument is performing nominally, Minus Diffuser Rotator. Cryotiger serviced and ion pump replaced on 2026-01-02
- 2026-01-05: The instrument is performing nominally, Minus Diffuser Rotator. Cryotiger serviced and ion pump replaced on 2026-01-02
- 2026-01-12: The instrument is performing nominally, Minus Diffuser Rotator.
KOSMOS
- 2026-01-26: Instrument is available for science.
- 2026-01-19: Instrument is available for science.
- 2026-01-12: Instrument is available for science.
- 2026-01-05: Instrument is available for science.
- 2026-01-12: Instrument is available for science.
NICFPS
- 2026-01-26: The instrument is performing nominally.
- 2026-01-19: The instrument is performing nominally.
- 2026-01-12: The instrument is performing nominally.
- 2026-01-05: The instrument is performing nominally.
- 2026-01-12: The instrument is performing nominally.
TRIPLESPEC
- 2026-01-26: The instrument is performing nominally.
- 2026-01-19: The instrument is performing nominally.
- 2026-01-12: The instrument is performing nominally.
- 2026-01-05: The instrument is performing nominally.
- 2026-01-12: The instrument is performing nominally.
MISC
NA2 GUIDER
- 2026-01-26: The instrument is operating nominally.
- 2026-01-19: The instrument is operating nominally.
- 2026-01-12: The instrument is operating nominally.
- 2026-01-05: The instrument is operating nominally.
- 2026-01-12: The instrument is operating nominally.
The information on this page is up to date as of January 26, 2026. This page is maintained by the 3.5-m Instrument Specialist .