All-Sky Airglow Imager


University Centre in Svalbard (UNIS)

Scientific objectives
The instrument is designed to image near-infrared emissions from the OH(6-2) band of airglow. The main objective is to study the morphology of the airglow layer at 90 km of altitude in the mesosphere. We expect to see how gravity waves and meteors interact with the layer in order to get a better understanding of the weather up there. Filter-ratio temperatures will be retrieved and compared to what we measure with the 1m Ebert-Fastie spectrometer (Silver Bullet).

Photo of the UNIS all-sky airglow camera
KeoSentry4ix airglow imager. (1) Mamiya RB67 Fish-eye lens, (2) collimator lens, (3) filterwheel, (4) Smart motor system, (5) relay optics, and (6) CCD detector

PIs: Fred Sigernes and Dag Lorentzen
Address: UNIS, P.O. Box 156, N-9171 Longyearbyen, Svalbard, Norway
E-mail: and
Phones/Fax: +47 79023335(6)/01

Instrument specifications
Manufacturer: Keo Scientific Ltd.
Name: KeoSentry4ix
Front Lens: Mamiya RB67
Spatial coverage: All sky view - FOV 180 deg.
Detector: Back Illuminated eXcellon PI PIXIS CCD 1024x1024 pixels;
Time resolution: 1s - and up!; Cooling: -70 deg.; 16 bits resolution
Filter wheel (6 x 4 inch diameter apertures - temperature stabilized):
[CH1] Blocked (dark images)
[CH2] Notch filter @ 844.6nm; BP 18.5 nm
[CH3] Bandpass filter @ 844.6nm; BP 1.8 nm
[CH4] Open (VIS & NIR)
[CH5] Bandpass filter @ 846.5nm; BP 1.8 nm
[CH6] Bandpass filter @ 840.0nm; BP 1.8 nm