Aqsaniq \'aks-a-'nEk\ n., from Inuit aqsarniit, northern lights. Aqsaniq is the nickname of one of two highly sensitive H-Beta all-sky imagers currently employed by the Institute for Space Research at the University of Calgary. These two imagers form the backbone of the NORSTAR chain of imagers, a project headed by Dr. Eric Donovan. Aqsaniq was tested during an initial field trip to Gillam, MB, Canada, March/April 2000 and was deployed at Rankin Inlet, Nunavut, in September of 2000.
The imager consists of an all-sky (fish-eye) lens that is imaged telecentrically onto a five-position, three-inch filterwheel containing narrow-band interference filters, typically about 20 Angstroms wide. Because the interference filters are temperature dependent (on the order of one Angstrom per five degrees C), an Athena XT16 stand-alone temperature controller is used to keep the temperature of the filters at approximately room temperature, or about 25 C. The temperature can be read/controlled remotely via a standard RS-232 serial interface. The filter is then re-imaged onto the front of a Gen-II type image intensifier which amplifies the image by a factor of 10,000. The intensifier photocathode is thermoelectrically cooled. Gain control of the image intensifier allows controlling the gain over 8:1. The image on the back of the image intensifier is then re-imaged onto the 512 x 512 pixels SITe CCD of a Photometrics Series 300 camera. The camera is thermoelectrically cooled to provide a decreased dark-noise accumulation and allow longer integration times. A shutter in front of the instrument is used to protect the filters from prolonged exposure to sunlight, and a light-detector at the front of the instrument is used as an automatic over-ride to avoid overexposure and possible damage to the intensifier. A standard RS-232 interface is used to control filterwheel, intensifier, and shutter operations. The optical system was designed and custom built for the University of Calgary by KEO Consultants, Brookline, MA, USA. System integration was performed by TS Trondsen at the U of C.
TST (trondsen@phys.ucalgary.ca) - Wed Jun 14 17:33:03 MDT 2000