SPECTRE is a proposed 0.4-4.2 µm low-resolution spectrograph being developed for the NASA Infrared Telescope Facility. Dispersion is accomplished using prisms to optimize throughput, resulting in a mean resolving power of R=160. SPECTRE has an image-slicer integral field unit with a 7.2′′ field of view to remove slit losses, reduce mechanical complexity, and enable precision spectrophotometry. Dichroics are used to divide the light into three spectroscopic channels, each with optimized optics and its own detector. We will use a 2K frame transfer CCD for the optical channel, and an H2RG in each of the two infrared channels. SPECTRE is a single mode instrument: there are no moving optics and the spectral format is fixed, making for a simple and rigid instrument. Guiding will be done by a co-mounted visible light camera with a 3′ field of view.
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