Eileen V. Ryan

Simultaneous infrared-visible imager/spectrograph: a multi-purpose instrument for the Magdalena Ridge Observatory 2.4-m telescope

The Simultaneous Infrared-Visible Imager/Spectrograph (SIRVIS) is a planned multi-purpose instrument for the Magdalena Ridge Observatory 2.4 m telescope located west of Socorro, NM. The primary science drivers are asteroid studies, the rapid response to astrophysical transient phenomena and observations of artificial targets such as satellites. For asteroid science, the wavelength range 0.39-2.5 μm gives the most mineralogically diagnostic information on surface compositions using standard filters and low-resolution, R ~ 200, spectroscopy. For transients, the telescopes rapid 10°/second slew rate will facilitate acquisition of data on any target within one minute of receipt of notice. For artificial targets, simultaneous two-color imaging will assist in unique determinations and overall condition monitoring. SIRVIS has two channels, a cryogenic NIR channel covering 0.85-2.5 μm at 0.27 arcsec/pixel, and an ambient temperature-pressure visible channel covering 0.39-1.0 μm at 0.15 arcsec/pixel. The beam is split by a cryogenic, red-pass dichroic mirror located between the telescope focal plane and the respective collimators. Both channels use refractive optics. The instrument is being designed to initially phase in the visible channel, then the NIR channel, and readily accommodate upgrades. For sky subtraction, the telescope is nodded between 30-60 second NIR integrations. Long visible integrations are made possible by shifting the CCD charge in sync with the nod.

The Magdalena Ridge Observatory 2.4 m Telescope

EOS Technologies has been commissioned to design and build a unique 2.4m astronomical telescope for the Magdalena Ridge Observatory. This telescope utilizes a high quality primary mirror and cell from a now decommissioned military application. This paper describes the project and gives an overview of the telescope design. The Magdalena Ridge Observatory (MRO) 2.4 meter telescope will be primarily utilized to observe, track, and characterize solar system astronomical targets, Earth satellites, space vehicles, and terrestrial military targets. The telescopes rapid tracking (slew rates are 10o/sec) will allow it to move to any target and acquire data within one minute of receipt of notice. In this way, the telescope will be used to capitalize on targets of opportunity that occur in asteroid studies (e.g., Near Earth Objects) and in astrophysics, such as gamma ray bursts and other transient phenomena. Planned instrumentation includes a CCD imager, and a low-resolution, wide-band Visible/IR spectrograph (Ryan et al. 2002). Both of these instruments will facilitate characterization studies of asteroids and space objects.