Keo Sentry


The 3- and 4-inch Keo Sentry, our flagship product, is the classic workhorse of allsky and narrow-field auroral imaging. Through careful optical design, all-sky (fisheye) imaging at speeds as fast as f/0.95 can be performed even through interference filters with bandwidths as narrow as 18Å FWHM. Constant, incremental improvements, based in large part on valuable customer feedback, have resulted in an imager that is more sensitive and robust than ever before. The included field-proven KeoSynopticx automatic ephemerides-driven instrument control & data acquisition software ensures a truly turn-key solution.


Custom Imagers


We are always excited to work with clients in designing novel, new imaging instrumentation uniquely addressing their research needs. Please contact us with your specific requirements (and/or with your concept ideas).

▶ Recent projects include the Keo Quad (photo), which places 4 x circular F0.95 all-sky (fish-eye) images neatly into the four quadrants of one large 27.6 x 27.6 mm CCD. Each image is 13.3 mm in diameter and all 4 images are acquired simultaneously through 4 separate narrowband filters (e.g., 427.8 nm, 486.1 nm, H-Beta background and 630 nm). Simultaneous imaging (as opposed to sequential imaging through a filter wheel) has several advantages when it comes to background subtraction and calculating emission-line intensity ratios. ▶ Another recent innovation includes f/0.95 fish-eye optics for a commercial full-frame format DSLR camera, for a client who needs images of the auroras that are scientifically useful as well as suited for Public Outreach purposes.

Keo Sentinel


The Keo Sentinel is a single-filter 3-inch wide-angle 'budget' imager for use in auroral (red-line, typically) and airglow remote sensing research. High sensitivity is achieved through F0.95 imaging onto the CCD. Our new quick-change filter drawer (held in place by two embedded rare-earth magnets) makes filter changes in the field a snap (for example, during campaigns). Our sliding focussing portclosed | open ] makes refocussing for the new filter easy. Absolute calibration service is available, enabling you to convert from raw pixel values to units of rayleighs. Sensor head is the Atik 4000. Due to the nominal cooling performance of this CCD, this imager does not deliver data anywhere near comparable to that of the Keo Sentry imagers. However, these low-cost imagers have proven to deliver eminently useful scientific data, given sufficient integration times. ▶ See brochure here.

Keo Horizon


The Keo Horizon comes in two sizes: 1" optics and 2" optics. Their low cost and relatively high sensitivity makes the Keo Horizon line of imagers an affordable building block for ground-based auroral imaging arrays. Keo delivered twenty of the 1" variant to U. C. Berkeley for the ground-based observatories (GBO) component of the NASA THEMIS mission. The University of Calgary THEMIS Team has deployed and are currently operating 16 of these imagers on Canadian soil. Four additional imagers are deployed in Alaska. Data are available online in realtime, after local sunset. Keo Scientific delivered a color version of this imager to the Canadian Space Agency for their AuroraMAX initiative.

THE LOW-COST 1-INCH OPTICS VERSION comes with a compact all-sky (fisheye) lens and includes fast panchromatic F0.95 imaging onto the CCD through a "hot mirror". Image capture takes place at high speed through a USB2 port. Sensor head options include monochrome and color sensor heads from Atik and StarlightXpress. Bistable inline shutter and shutter controller unit with USB interface is also available.

THE HIGHER-PERFORMING 2-INCH VERSION of this all-sky imager includes fast F0.95 imaging onto a larger CCD through narrow- or wide-band 2-inch diameter interference filter(s). Sensor head options include the low-cost Atik 314L+, the StarlightXpress SXVR-H9 (monochrome) or SXVR-H9C (color), or for superior performance the P.I. Acton ProEM:512B EMCCD camera. Custom narrow FoVs, filter-wheel and bistable shutter are available.



In November of 2009, Keo Scientific Ltd. teamed up with Dr. Fred Sigernes of the UNIS Kjell Henriksen Observatory, Svalbard, Norway, Dr. Yuri Fedorenko and his team at the Russian Polar Geophysical Institute, as well as Dr. Yuriy Ivanov (Zemax guru extraordinaire, of Ukraine) on a research project called The Norwegian and Russian Upper Atmosphere Co-Operation on Svalbard Part 2 (NORUSCA II). This Norwegian-Russian collaboration is funded by the Norwegian Research Council.

An important component of NORUSCA-II involved designing a compact but sensitive allsky imager suitable for auroral studies, a component Keo Scientific provided significant input to. More information on the resulting NORUSCA-II Imager is found here.

Keo Scientific Ltd. is pleased to offer for sale to the community a limited number of these imagers.

The imager accepts a 35 mm diameter interference filter (or a Liquid Crystal Tunable Filter) and is eminently suitable for panchromatic or filtered observations of aurora, twilight/dawn phenomena, stratospheric clouds, and meteor observations.

The imager comes complete with a P.I. Acton ProEM 512B EMCCD camera (8.2 mm x 8.2 mm CCD), filter(s) of your choice, and data acquisition software.

Here is the published instrument paper, and a paper on the calibration of the imager. Finally, a letter describing some of the extensive news coverage the instrument received.


  • Paraxial focal length: 3.5 mm
  • FOV: 180 degrees
  • Linear FOV on CCD: 8.0 mm diameter circle
  • F-number: f/1.1
  • Spectral range: 430–750 nm
  • Resolution: 100 lp/mm center, 80 lp/mm (edge)
  • Lens mount: C-mount
  • Optics Dimensions: 320 mm length, 110 mm max diameter
  • MTF performance
  • Vignetting performance
TO FURTHER UNDERSCORE the close relationship between Keo Scientific and The Kjell Henriksen Observatory, Svalbard, we are proud to mention that in 2010, Keo Scientific delivered a 4-inch imager to UNIS (instrument page at UNIS), now being operated by Dr. Sigernes and generating good data. The Keo Sentry imager can be seen inspected by Her Majesty Queen Sonja of Norway in this video clip. 2010 also saw the delivery of a 3-inch imager to the Polar Research Institute of China, who are now operating it at the KHO (along with 4 identical imagers at their Zhongshan Station in Antarctica), as well as a 4-inch imager to the University of Oslo (operating out of Ny Ålesund, Svalbard). Several other deliveries — imagers as well as FPIs — to Svalbard are scheduled for the 2015–2016 time frame.