Apache Point Observatory
New Mexico, USA

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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.
• DIS is available. See below for more information.
• AGILE is NOT 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.

• NOTE (2012-01-24): APO still does not recommend taking dome flats with AGILE. More information can be found here.
• 2024/2025 Until further notice: Instrument CCD thermal electric cooler (TEC) has failed. We have been unable to bring it back at this time. The camera is unavailable for use until cooling can be restored. Thermalcontrol and CCD readout is onthe same board so it is not a simple matter to troubleshoot.
• 2025-01-13: The camera is back out for repair. Programmable gain control was no longer available. Sent back to evaluate the problem. RAM was changed but did not correct the problem. Awaiting a further status report.
• 2025-01-06: The camera is back out for repair. Programmable gain control was no longer available. Sent back to evaluate the problem. Awaiting a status report.
• 2025-01-02: The camera is back out for repair. Programmable gain control was no longer available. Sent back to evaluate the problem. Awaiting a status report.

• NOTE (2022): Most recent interorder ratio plot can be found here.
• 2025-01-13: The instrument IOL is excellent.
• 2025-01-06: The instrument IOL is excellent.
• 2025-01-02: The instrument IOL is excellent.

• NOTE: 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.
• 2025-01-13: The instrument is performing nominally except for the known water spots on the fore optics.
• 2025-01-06: The instrument ion pump was replaced, the cryostat evacuated and instrument cooled.
• 2025-01-03: The instrument ion pump failed in the early hours of the morning. Placed instrument of vacuum pump and started warming. Will change out the ion pump when the cryostat is above freezing.
• 2025-01-02: The instrument ion pump is still struggling to maintain vaccum. We are looking for windows to replace it. Instrument rotation range on the NA2 guider has been restricted to +/- 90 degrees.

• 2025-01-13: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2025-01-06: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2025-01-02: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.

• 2025-01-13: Instrument is available for science and performing nominally.
• 2025-01-06: Instrument is available for science and performing nominally.
• 2025-01-02: Instrument is available for science and performing nominally.

• 2025-01-13: The instrument is performing nominally.
• 2025-01-06: The instrument is performing nominally.
• 2025-01-02: The instrument is performing nominally.

• 2025-01-13: The instrument is performing nominally.
• 2025-01-06: The instrument is performing nominally.
• 2025-01-02: The instrument is performing nominally.

• 2025-01-13: The instrument is operating nominally.
• 2025-01-06: The instrument is operating nominally.
• 2025-01-02: The instrument is operating nominally.

The information on this page is up to date as of January 16, 2025. This page is maintained by the 3.5-m Telescope Engineer .