From Event: SPIE Optical Engineering + Applications, 2019
THE MOST, The High Étendue Multiple Object Spectrographic Telescope, is a Primary Objective Grating (POG) telescope based on a Newtonian double dispersion architecture. Because it is inexpensive to scale up to large collecting area, this telescope could make an extraordinary spectroscopic survey instrument for astronomy. We describe here the laboratory tests on a scale model. We used two light sources to simulate starlight: The first was a blackbody incandescent filament in a flashlight. The other was a research-grade collimated laser. Both sources focused to 5 cm diameter circles with controlled angles of incidence. We tested two flat surface-relief reflection plane gratings as the POG in the scale model. The first POG was a conventionally ruled 4 cm2, 1180 line/mm grating mounted on a glass plate. The other POG was a 750×300 mm holographically mastered 1600 line/mm embossed decorative crating on polyester film, sold commercially as Holosheen. We report on experiments that compared resolution in the first-order diffracted image with the zero-order reflection image. Our report provides empirical evidence that along the diffraction axis THE MOST figure tolerances are vastly relaxed compared to mirror and lens telescopes. We measure the throughput of the Holosheen decorative grating to be 14% in the first order. We estimate the rate of SDSS-like spectrum acquisition from THE MOST in comparison to that of the Sloan Digital Sky Survey (SDSS) as an example, though this survey is not optimized to take advantage of the unique capabilities of THE MOST.
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Thomas D. Ditto, Heidi Jo Newberg, J. Hiroshi Burnette, Hunter Rouillard, and Makayla Wahaus, "Scale model of a dual dispersion primary objective grating telescope," Proc. SPIE 11116, Astronomical Optics: Design, Manufacture, and Test of Space and Ground Systems II, 111160A (Presented at SPIE Optical Engineering + Applications: August 13, 2019; Published: 9 September 2019); https://doi.org/10.1117/12.2528951.
