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.

• 2024 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.
• 2024-12-09: The camera is back out for repair. When it returned the TEC had been repaired but the programmable gain control was no longer available. Sent back to evaluate the problem. Awaiting a report.
• 2024-11-25: The camera is back out for repair. When it returned the TEC had been repaired but the programmable gain control was no longer available. Sent back to evaluate the problem.
• 2024-07-31: The camera is out for repair. Investigation into a failed TEC is being done at a repair facility.
• 2024-03-25: 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.
• 2012-01-24: APO still does not recommend taking dome flats with AGILE. More information can be found here.

• 2022: Most recent interorder ratio plot can be found here.
• 2024-12-16: The instrument IOL is excellent.
• 2024-12-09: The instrument IOL is excellent.
• 2024-12-02: The instrument IOL is excellent.
• 2024-11-25: The instrument IOL is excellent.
• 2024-11-18: The instrument IOL is excellent.
• 2024-11-11: The instrument IOL is excellent.
• 2024-11-04: The instrument IOL is excellent.
• 2024-10-28: The instrument IOL is excellent.
• 2024-10-21: The instrument IOL is excellent.
• 2024-10-14: The instrument IOL is excellent.
• 2024-10-07: The instrument IOL is excellent.
• 2024-09-30: The instrument IOL is excellent.
• 2024-09-23: The instrument IOL is excellent.
• 2024-09-16: The instrument IOL is excellent.
• 2024-09-09: The instrument IOL is excellent.
• 2024-09-03: The instrument IOL is excellent.
• 2024-08-26: The instrument IOL is excellent.
• 2024-08-19: The instrument IOL is excellent.
• 2024-08-12: The instrument IOL is excellent.
• 2024-08-05: The instrument IOL is excellent.
• 2024-07-31: The instrument IOL is excellent. It appears to be increasing slowly.
• 2024-07-30: The instrument had a failure of the CCD Reservoir fill/splash sensor last night. The instrument partially warmed. Critical alerts did not notifiy the telescope operator. We wera ble to recover within 6 hours and IOL measuremnts returned to nominal.
• 2024-07-01: The instrument IOL is excellent. It appears to be leveling off.
• 2024-06-24: The instrument IOL is excellent. It appears to be leveling off.
• 2024-06-17: The instrument IOL is excellent. It appears to be leveling off.
• 2024-06-10: The instrument IOL is excellent. It appears to be leveling off.
• 2024-06-03: The instrument IOL is excellent. It appears to be leveling off.
• 2024-05-28: The instrument IOL is excellent. It appears to be leveling off.
• 2024-05-20: The instrument IOL is excellent but has a linear downward trend.
• 2024-05-13: The instrument IOL is excellent but has a linear downward trend.
• 2024-05-06: The instrument IOL is excellent but has a linear downward trend.
• 2024-04-29: The instrument IOL is excellent but has a linear downward trend.
• 2024-04-22: The instrument IOL is excellent but has a linear downward trend.
• 2024-04-15: The instrument IOL is excellent but has a linear downward trend.
• 2024-04-08: The instrument IOL is excellent.
• 2024-04-01: The instrument IOL is excellent.
• 2024-03-25: The instrument IOL is excellent. It is available for use.

• 2024-12-19: The instrument unexpectedly lost vacuum when inverted last night at 11:15pm. This morning we were able to recover and get the ion pump to release some of the whiskers that were shorting the anode/cathode.
• 2024-12-18: The instrument is cold again.
• 2024-12-17: The instrument vacuum went soft. Warmed and pumped.
• 2024-12-16: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-12-09: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-12-02: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-11-25: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-11-18: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-11-11: Short vacuum pumping cycle over a couple of days. Recent ion pump controller and site generator testing ( cryotiger 'burps'/partial warmups) have caused the camera vacuum to go soft. Hope to pump during engineering and will be available again for science Wednesday night. The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-11-04: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-10-28: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-10-21: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-10-14: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-10-07: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-09-30: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-09-23: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-09-16: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-09-09: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-09-03: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-08-26: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-08-19: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-08-12: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-08-05: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-07-31: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-07-01: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-06-24: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-06-17: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-06-10: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-06-03: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-05-28: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-05-20: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-05-13: The instrument is performing nominally except for the water spots still exist on the fore optics. Diffuser servicing completed.
• 2024-05-06: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-04-29: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-04-22: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-04-15: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-04-14: Dropped quad this weekend due to a wedged ICC. Russet recovered the Quad at 205K.
• 2024-04-08: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-04-01: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024-03-25: The instrument is performing nominally except for the water spots still exist on the fore optics.
• 2024: 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.

• 2024-12-16: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-12-09: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-12-02: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-11-25: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-11-18: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-11-11: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-11-04: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-10-28: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-10-21: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-10-14: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-10-07: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-09-30: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-09-23: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-09-16: Marked degradation for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-09-09: Marked degradation for ccd contamination on both cameras as measured last night. The instrument is performing nominally otherwise.
• 2024-09-03: Marked degradation for ccd contamination on both cameras as measured last night. The instrument is performing nominally otherwise.
• 2024-08-26: Marked degradation for ccd contamination on both cameras as measured last night. The instrument is performing nominally otherwise.
• 2024-08-19: Marked degradation for ccd contamination on both cameras as measured last night. The instrument is performing nominally otherwise.
• 2024-08-12: Marked degradation for ccd contamination on both cameras as measured last night. The instrument is performing nominally otherwise.
• 2024-08-05: Marked degradation for ccd contamination on both cameras as measured last night. The instrument is performing nominally otherwise.
• 2024-07-31: Slight improvement for ccd contamination on both cameras. The blue camera is running warm which is not unusual for this time of year. The instrument is performing nominally otherwise.
• 2024-07-01: Slightimprovement for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-06-26: Slightimprovement for ccd contamination on both cameras. The instrument is performing nominally otherwise.
• 2024-06-24: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-06-17: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-06-10: Not much new to report on ccd contamination. REd contamination broad wings are starting to blend into the core of point sources. The instrument is performing nominally otherwise.
• 2024-06-03: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-05-28: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-05-20: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-05-13: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-05-06: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-04-29: Not much new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-04-22: Not much new to report on ccd contamination. Russet says she will evaluate duringthis weeks engineering time Tuesday or Wednesday. The instrument is performing nominally otherwise.
• 2024-04-15: Notmuch new to report on ccd contamination. The instrument is performing nominally otherwise.
• 2024-04-09: Gordon was able to bring the ICC back up and usable for now. We willneed to order rplacement drives and rebuild the RAID. The instrument is available for use in the mean time.
• 2024-04-08: There is a failure of the primary hard drive on the ICC. We are investigating repair. Until it is fixed the instrument is not available for use.
• 2024-04-01: Report from Russet: Contamination check last week. Blue is the same or slightly improved. Red is resuming progress in a direction that I think should resolve contamination, hopefully sometime in April or May.
• 2024-03-25: Report from Russet: Contamination check last week. Blue is the same as 3 weeks ago. Red is resuming progress in a direction that I think should resolve contamination, hopefully sometime in April or May.

• 2024-12-16: Instrument is available for science and performing nominally.
• 2024-12-09: Instrument is available for science and performing nominally.
• 2024-12-02: Instrument is available for science and performing nominally.
• 2024-11-25: Instrument is available for science and performing nominally.
• 2024-11-18: Instrument is available for science and performing nominally.
• 2024-11-11: Instrument is available for science and performing nominally.
• 2024-11-04: Instrument is available for science and performing nominally.
• 2024-10-28: Instrument is available for science and performing nominally.
• 2024-10-21: Instrument is available for science and performing nominally.
• 2024-10-14: Instrument is available for science and performing nominally.
• 2024-10-07: Instrument is available for science and performing nominally.
• 2024-09-30: Instrument is available for science and performing nominally.
• 2024-09-23: Instrument is available for science and performing nominally.
• 2024-09-16: Instrument is available for science and performing nominally.
• 2024-09-09: Instrument is available for science and performing nominally.
• 2024-09-03: Instrument is available for science and performing nominally.
• 2024-08-26: Instrument is available for science and performing nominally.
• 2024-08-19: Instrument is available for science and performing nominally.
• 2024-08-12: Instrument is available for science and performing nominally.
• 2024-08-05: Instrument is available for science and performing nominally.
• 2024-07-31: Instrument is available for science and performing nominally.
• 2024-07-01: Instrument is available for science and performing nominally.
• 2024-06-26: Instrument is available for science and performing nominally.
• 2024-06-24: Instrument is NOT available for science, performing vacuum servicing.
• 2024-06-17: Instrument is available for science and performing nominally.
• 2024-06-10: Instrument is available for science and performing nominally.
• 2024-06-03: Instrument is available for science and performing nominally. New 1.25" slits were tested on sky during engineering last Thursday evening. Performance appears to be acceptable with the exception of the screw heads now in the field of view of the center slit.
• 2024-05-28: Instrument is available for science and performing nominally. New 1.25" slits were tested on sky during engineering last Thursday evening. Performance appears to be acceptable with the exception of the screw heads now in the field of view of the center slit.
• 2024-05-20: Instrument is available for science and performing nominally. New 1.25" slits scheduled to be tested on sky during engineering Wednesday or Thursday evening.
• 2024-05-13: Instrument is available for science and performing nominally. Slits are on site but will need testing on sky.
• 2024-05-06: Instrument is available for science and performing nominally. Slits should arrive later today.
• 2024-04-29: Instrument is available for science and performing nominally. No update on new slits.
• 2024-04-22: Instrument is available for science and performing nominally. No update on new slits.
• 2024-04-15: Instrument is available for science and performing nominally. UWTEG report the next attempt at 1.25" slits will be delayed further due to a problem in Quality Control.
• 2024-04-08: Instrument is available for science and performing nominally. UWTEG report the next attempt at 1.25" slits will be complete later in April.
• 2024-04-01: Instrument is available for science and performing nominally. UWTEG report the next attempt at 1.25" slits will be complete later in April.
• 2024-03-25: Instrument is available for science and performing nominally. There was a need to restart software last week when an exposure froze for a science observation but the recovery was quick. UWTEG report the next attempt at 1.25" slits will be complete in abut 3 weeks.

• 2024-12-16: The instrument is performing nominally.
• 2024-12-09: The instrument is performing nominally.
• 2024-12-02: The instrument is performing nominally.
• 2024-11-25: The instrument is performing nominally.
• 2024-11-18: The instrument is performing nominally.
• 2024-11-11: The instrument is performing nominally.
• 2024-11-04: The instrument is performing nominally.
• 2024-10-28: The instrument is performing nominally.
• 2024-10-21: The instrument is performing nominally.
• 2024-10-14: The instrument is performing nominally.
• 2024-10-07: The instrument is performing nominally.
• 2024-09-30: The instrument is performing nominally.
• 2024-09-23: The instrument is performing nominally.
• 2024-09-16: The instrument is performing nominally.
• 2024-09-09: The instrument is performing nominally.
• 2024-09-03: The instrument is performing nominally.
• 2024-08-26: The instrument is performing nominally.
• 2024-08-19: The instrument is warm for servicing.
• 2024-08-12: The instrument is warm for servicing.
• 2024-08-05: The instrument is warm for servicing.
• 2024-07-31: The instrument had a vacuum failure a week ago (21st). It has been warmed for servicing.
• 2024-07-01: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-06-24: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-06-17: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-06-10: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-06-03: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-05-28: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-05-20: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-05-13: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-05-06: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-04-29: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-04-22: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-04-15: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-04-08: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-04-01: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.
• 2024-03-25: The instrument rotation has been restricted to less than its full range (rotator angle = -90 to +90) to reduce the number of resets required. The instrument is performing nominally with the occasional need to reset the array controller due to corrupted images.

• 2024-12-16: The instrument is performing nominally.
• 2024-12-09: The instrument is performing nominally.
• 2024-12-02: The instrument is performing nominally.
• 2024-11-25: The instrument is performing nominally.
• 2024-11-18: The instrument is performing nominally.
• 2024-11-11: The instrument is performing nominally.
• 2024-11-04: The instrument is performing nominally.
• 2024-10-28: The instrument is performing nominally.
• 2024-10-21: The instrument is performing nominally.
• 2024-10-14: The instrument is performing nominally.
• 2024-10-07: The instrument is performing nominally.
• 2024-09-30: The instrument is performing nominally.
• 2024-09-23: The instrument is performing nominally.
• 2024-09-16: The instrument is performing nominally.
• 2024-09-09: The instrument is performing nominally.
• 2024-09-03: The instrument is performing nominally.
• 2024-08-26: The instrument is performing nominally.
• 2024-08-19: The instrument is performing nominally.
• 2024-08-12: The instrument is performing nominally.
• 2024-08-05: The instrument is performing nominally.
• 2024-07-01: The instrument is performing nominally.
• 2024-07-01: The instrument is performing nominally.
• 2024-06-24: The instrument is performing nominally.
• 2024-06-17: The instrument is performing nominally.
• 2024-06-13: The instrument is performing nominally. TSPEC-ICC and TCAMERA-ICC iRAID repairs will continue during summer shutdown.
• 2024-06-12: Took tspec-icc and tcamera-icc computers down for maintenance (repair of RAID drives). Tspec-icc RAID rebuild went smoothly. Tcamera-icc did not come back cleanly. Shane and Tracey were able to get it come back up but it may take some time to rebuild its RAID. The instrument is not available until work is complete. Expect to have back Thursday (tomorrow).
• 2024-06-10: The instrument is performing nominally.
• 2024-06-03: The instrument is performing nominally.
• 2024-05-28: The instrument is performing nominally.
• 2024-05-20: The instrument is performing nominally.
• 2024-05-13: The instrument is performing nominally. Waiting for quotes on replacement hardware for TSpec-icc and Tcamera-icc computers.
• 2024-05-06: The instrument is performing nominally. Waiting for quotes on replacement hardware for TSpec-icc and Tcamera-icc computers.
• 2024-04-29: The instrument is performing nominally. Waiting for quotes on replacement hardware for TSpec-icc and Tcamera-icc computers.
• 2024-04-22: The instrument is performing nominally. Waiting for quotes on replacement hardware for TSpec-icc and Tcamera-icc computers.
• 2024-04-15: The instrument is performing nominally. Researching replacementhardware for TSpec-icc and Tcamera-icc computers.
• 2024-04-08: The instrument is performing nominally.
• 2024-04-01: The instrument is performing nominally.
• 2024-03-25: The instrument is performing nominally.

• 2024-12-16: The instrument is operating nominally.
• 2024-12-09: The instrument is operating nominally.
• 2024-12-02: The instrument is operating nominally.
• 2024-11-25: The instrument is operating nominally.
• 2024-11-18: The instrument is operating nominally.
• 2024-11-11: The instrument is operating nominally.
• 2024-11-04: The instrument is operating nominally.
• 2024-10-28: The instrument is operating nominally.
• 2024-10-21: The instrument is operating nominally.
• 2024-10-14: The instrument is operating nominally.
• 2024-10-07: The instrument is operating nominally.
• 2024-09-30: The instrument is operating nominally.
• 2024-09-23: The instrument is operating nominally.
• 2024-09-16: The instrument is operating nominally.
• 2024-09-09: The instrument is operating nominally.
• 2024-09-03: The instrument is operating nominally.
• 2024-08-26: The instrument is operating nominally.
• 2024-08-19: The instrument is operating nominally.
• 2024-08-12: The instrument is operating nominally.
• 2024-08-05: The instrument is operating nominally.
• 2024-07-31: The instrument is operating nominally.
• 2024-07-01: The instrument is operating nominally.
• 2024-06-24: The instrument is operating nominally.
• 2024-06-17: The instrument is operating nominally.
• 2024-06-10: The instrument is operating nominally.
• 2024-06-03: The instrument is operating nominally.
• 2024-05-28: The instrument is operating nominally.
• 2024-05-20: The instrument is operating nominally.
• 2024-05-13: The instrument is operating nominally.
• 2024-05-06: The instrument is operating nominally.
• 2024-04-29: The instrument is operating nominally.
• 2024-04-22: The instrument is operating nominally.
• 2024-04-15: The instrument is operating nominally.
• 2024-04-08: The instrument is operating nominally.
• 2024-04-01: The instrument is operating nominally.
• 2024-03-25: The instrument is operating nominally.

The information on this page is up to date as of December 16, 2024. This page is maintained by the 3.5-m Telescope Engineer .