GeminiFocus July 2017 | Page 19

Lastly, Gemini Senior Mechanical Group Leader Gabriel Pérez com- pleted the design of the interface between the Toptica Laser Head and the Beam Transfer Optics (BTO), and it is now ready for fabrication. — Manuel Lazo ‘Alopeke Settles in at Gemini North In October, Steve Howell and his team will plan to commission a new speckle instrument named ‘Alopeke. The instrument is to be mounted on the Gemini North telescope as a Gemini Visiting In- strument. Speckle imaging is an interferometric technique by which telescopes can achieve diffraction- limited imaging performance using Fourier image reconstruction techniques with cam- eras that are capable of reading out frames at a very fast rate. The images, reduced us- ing specialized software, allow scientists to effectively “freeze out” the effects of atmo- spheric seeing and perform the equivalent of space-based imaging with ground-based telescopes. The design of ‘Alopeke is based on the Differ- ential Speckle Survey Instrument (DSSI). The original DSSI has been a popular Visiting In- strument at Gemini since 2012. Making ob- servations at both Gemini North and South, DSSI has provided simultaneous diffraction- limited optical imaging — Full-Width at Half- Maximum (FWHM) ~0.02” at 650 nanome- ters (nm) — of targets as faint as V ~16–17, in two channels over a ~2.8” field-of-view. The diffraction-limited resolution possible at Gemini (0.016” FWHM at 500 nm or 0.025” at 800 nm), with no need for an adaptive optics guide star or laser, offers unique scientific ca- pabilities. July 2017 Figure 5. The most recent DSSI visit to Gemini South was marred slightly by unstable weather, but in the end, the team obtained data on a large range of projects from follow-up vali- dation of exoplanet candidates to a search for close binary companions of exoplanet host stars, as well as a study of the rate of bi- narity in low mass star forming regions. ‘Alopeke is the contemporary Hawaiian word for fox, and this name was chosen for the newest member of the DSSI family be- cause it is very agile and quick. The new dual-channel instrument will have a larger format than the previous version, modern GeminiFocus The Toptica Laser Interlock System Data Manager screen. Angelic Ebbers developed it as part of the Experimental Physics and Industrial Control System (EPICS) code to interact with existing parts of Gemini South telescope’s safety subsystems. It also interacts with the safety aspects and feedbacks of the Toptica Systems; Paul Collins developed the latter in a Programmable Logic Controller environment. Figure 6. The design of the Toptica Laser Beam Injector Interface to the telescope Beam Transfer Optics by Gabriel Pérez. 17