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GEONIS Feasibility Study


The Gemini Efficient Optical and Near-infrared Imager and Spectrograph (GEONIS) study was led by Nick Konidaris and managed by Dan Reiley at the California Institute of Technology. Main collaborators included astronomers at the University of Colorado Boulder, Penn State University, University of Toronto, the Jet Propulsion Laboratory and the US National Optical Astronomy Observatory.  The study began in April 2015 and concluded in October 2015.

Executive Summary [Extracted from the GEONIS final report]

The astronomical landscape in the coming decade will be dominated by next generation wide-field synoptic surveys at every wavelength: optical (TESS, ZTF, LSST), infrared (JWST, NeoWISE, NEOCAM, WFIRST), ultraviolet (ULTRASAT), radio (LOFAR, LWA, SKA, ALMA). Experience with current surveys (e.g. SDSS, PTF) has shown that spectroscopic follow-up holds the key to unraveling the astrophysics and hence, realizing the science from discoveries by synoptic surveys.

A comparative analysis of various instruments on large aperture telescopes has shown that the primary workhorse (in units of papers, citations, and time usage) is the spectrograph. Thus, the success of an observatory is closely tied to the quality and efficiency of its instrumentation with the highest bar being set for its spectrographs.

To determine the science requirements of a next generation spectrograph, we studied three ongoing large and long term programs at Gemini: near earth asteroids (PI Masiero), extrasolar planets (PI Desert) and transients (PI Kasliwal).

Driven by the science requirements, we propose GEONIS - a spectrograph designed with the goal of maximizing every iota of efficiency while enabling a breadth of new science. GEONIS will deliver wavelength coverage spanning 400 nm to 1,600 nm with a tunable resolution leveraging high-speed low-read-noise detectors. To boost instrument efficiency, GEONIS will have a slit-viewing camera, atmospheric dispersion compensation system, and flexure compensation system that will maximize the fraction of time Gemini is collecting science photons and minimize overhead.

GEONIS capitalizes on Gemini's unique strengths. In particular, Gemini's successful queue observing mode is well-suited to rapid response classification of events discovered by synoptic surveys. We propose to operate GEONIS in classification driven observing mode such that on-the-fly reduced spectra directly determine the next steps in the panchromatic follow-up sequence. This opens up a new paradigm of minute-timescale response to the fastest relativistic explosions, the youngest supernovae and the rarest neutron-star mergers.

Our vision is that GEONIS leads the way in leveraging the science potential of discoveries from the James Webb Space Telescope (JWST), Large Synoptic Survey Telescope (LSST), advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO), Transiting Exoplanet Survey Satellite (TESS), and the Wide-Field infrared Survey Telescope (WFIRST).

The GEONIS concept meets the aforementioned science requirements and fits within the cost cap of $12M (projected at $10.4M, with a variance up to $12.4M), mass limit of 2 ton (projected at 1.6 ton, without contingency), and volume limits of Gemini instrumentation. From start to first light GEONIS is projected to take almost six years.


The GEONIS Deliverable are available to download: 

Contact Information

For more information of the GEONIS study, please contact the Project Manager:
Dan Reiley:               

For more information about GIFS or Gen4#3, please contact the Gemini Instrumentation Program Manager:

Stephen Goodsell:   

Please visit the Gen 4#3 home page for the latest information.