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Overview of Capabilities

'Alopeke (Hawaiian for "fox") is a fast low-noise dual-channel and dual-plate-scale imager based on the Differential Speckle Survey Instrument (DSSI, Horch et al.2009, 2012) permanently mounted on the calibration port at Gemini North. In speckle mode 'Alopeke provides simultaneous two-color diffraction-limited optical imaging (FWHM~0.02" at 650nm) of targets as faint as V~17 over a 6.7" field of view. Wide-field mode provides simultaneous two-color imaging in standard SDSS filters over a 60" field of view.

'Alopeke was built in 2017 and uses two identical Andor iXon Ultra 888 EMCCD cameras. These 1024x1024 detectors have 13 μm pixels and are capable of 26 fps readout of the full chip, and faster readouts are possible for subarrays. They have an EX coating with > 80% quantum efficiency from 420 to 780 nm and > 90% QE between 550 and 720 nm.

A fixed dichroic splits the input telescope beam at 674 nm, with blue light reflected to the blue filter wheel and red transmitted to the red filter wheel. The plate scale is 0.0096"/pix in speckle mode and 0.0725"/pix in wide-field mode. The cameras underfill the detectors yielding circular fields of view of 6.7" in speckle mode and 60" in wide-field mode.

The standard procedure for speckle imaging at Gemini is to operate the EMCCDs using 60 msec exposures, and gather images in sets of 1000 frames.

The visiting instrument team will take all observations and will provide their standard pipeline-reduced data products to PIs. There is no requirement to collaborate with the instrument PI for this level of service. If you need more than this, then the PI would appreciate an offer to collaborate. All raw and reduced data will be made available via the Gemini Observatory Archive.

The PI for the Gemini Speckle program is Steve Howell (NASA Ames Research Center).


'Alopeke will be available in 2018A. Please see the Status and Availability pages for more information.

How to Use These Pages

The 'Alopeke pages are organized as follows:

Gemini Observatory Participants