ARCTIC is an optical imager built at the University of Washington and APO.
A wide set of filters in available. These include a diffuser, which can be used in a rotating wheel to provide diffused images to allow for high-precision photometry of bright sources, although the diffuser rotation mechanism has been a challenge to get to work reliably.
* When operated in quad-mode, the overscan regions for each quadrant are located in-between the quadrants; the quadrants must be properly stiched together to get a contiguous image, but there are no actual spatial gaps
* the cosmic ray rate is very high, related to the glass used in the instrument
* dark current is non-negligible in ARCTIC, even for relatively short exposures
For reducing quad-mode data, special IRAF CL scripts can be obtained here: quad.tar. See the quad-mode data reduction manual for instructions.
* PDR Mechanical Design: ftp://ftp.apo.nmsu.edu/pub/users/jwhueh/arctic/APOImager_Assem_20131028.zip APOImager_Assem_20131028.zip](77mb) * Final Mechanical Design: ftp://ftp.apo.nmsu.edu/pub/users/jwhueh/arctic/20150501_APOImager_Assem_V3.zip 20150501_APOImager_Assem_V3.zip (102mb) * Mounting plate description: Mounting plate PDF * SW Pack and Go: http://users.apo.nmsu.edu/~jwhueh/APOImager/mounting_plate_fit_assem.zip mounting_plate_fit_assem.zip
[attachment:full_assem.avi Instrument Cart Movie] (40mb)
[wiki:Diffuser Information about ARCTIC diffuser]
Joanne Hughes Clark has provided a series of dome and sky flats that can be used to assess the vignetting across the ARCTIC FOV due to the NA2 baffle. The files (a readme file and a tar file containing all the flats) can be obtained here: https://www.dropbox.com/sh/bp495m0lla236nz/AAA3Tm6LuDS2_gqbz9GvPz2ra?dl=0
With the failure of the thermoelectric cooler on Agile in July 2023, users may wish to consider the use of ARCTIC for high cadence imaging applications. In late July Russet McMillan conducted some tests of various readout modes of ARTIC. Those results can be found here: July 2023 ARCTIC speed tests.