FASTTRAC I: A High Resolution Infrared Tip-Tilt Imager
Session 42 -- High-Spatial Resolution
Display presentation, Tuesday, 10, 1995, 9:20am - 6:30pm

## [42.06] FASTTRAC I: A High Resolution Infrared Tip-Tilt Imager

Laird M. Close, David Wittman, Donald W. McCarthy, \& Marica Rieke (CAAO, Steward Observatory, University of Arizona)

The Center for Astronomical Adaptive Optics (CAAO) at Steward Observatory is implementing instrumentation to enable high resolution imaging in the infrared. The FASTTRAC I instrumentation suite achieves diffraction limited imaging (or spectroscopy) in the near infrared $(1-2.4 \mu m)$ by rapid $(100 Hz)$ tip-tilt correction in typical seeing conditions $(r_{o}=10 cm$ at $0.5 \mu m)$. FASTTRAC I removes image motion by rapidly steering a reactionless tip-tilt secondary mirror cell which economically accommodates existing IR secondaries at both the Observatory's 2.3m and 1.5m Cassegrains. Image motion is reduced to less than $0.05" rms$ during long exposures resulting in final image resolutions of $0.2-0.6"$ FWHM. Science targets can be acquired by utilizing faint visible $(\le 17^{th} V)$ or infrared $(\le 8^{th} K)$ guide stars (a unique dual capability). These guide stars must be within a $3'$ FOV which allows nearly full sky coverage for science target acquisition.

A few examples of science targets already acquired by FASTTRAC I are: the first real time images (J, H, \& K) of the massive black hole candidate Sgr A* FWHM $\le 0.5"$, the first high resolution HeI $(2.06 \mu m)$ image of the Galactic Center, high resolution infrared images of faint $(K \sim 22)$ field galaxies imaged by HST in the visible, Seyfert galaxy morphologies, and high redshift sub-arcsecond gravitational lenses. We will soon obtain tip-tilt corrected near infrared spectra of Sgr A* and other interesting infrared sources.

This research is supported by grants from the NSF (AST 88-22465; AST 92-03336) and NASA (NAGW-2254). L.M. Close is supported by a NSERC Fellowship.