Million object spectrograph

Thomas D. Ditto; Joseph M. Ritter

doi:10.1117/12.790244

23 July 2008 Million object spectrograph

Thomas D. Ditto, Joseph M. Ritter

Proceedings Volume 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation; 70182R (2008) https://doi.org/10.1117/12.790244
Event: SPIE Astronomical Telescopes + Instrumentation, 2008, Marseille, France

Abstract

A new class of astronomical telescope with a primary objective grating (POG) has been studied as an alternative to mirrors. Nineteenth century POG telescopes suffered from low resolution and ambiguity of overlapping spectra as well as background noise. The present design uses a conventional secondary spectrograph to disambiguate all objects while enjoying a very wide instantaneous field-of-view, up to 40°. The POG competes with mirrors, in part, because diffraction gratings provide the very chromatic dispersion that mirrors defeat. The resulting telescope deals effectively with long-standing restrictions on multiple object spectrographs (MOS). The combination of a POG operating in the first-order, coupled to a spectrographic astronomical telescope, isolates spectra from all objects in the free spectral range of the primary. First disclosed as a concept in year 2002, a physical proof-of-principle is now reported. The miniature laboratory model used a 50 mm plane grating primary and was able to disambiguate between objects appearing at angular resolutions of 55 arcseconds and spectral spacings of 0.15 nm. Astronomical performance is a matter of increasing instrument size. A POG configured according to our specifications has no moving parts during observations and is extensible to any length that can be held flat to tolerances approaching float glass. The resulting telescope could record over one million spectra per night of objects in a line of right ascension. The novel MOS does not require pre-imaging to start acquisition of uncharted star fields. Problems are anticipated in calibration and integration time. We propose means to ameliorate them.

Citation Download Citation

Thomas D. Ditto and Joseph M. Ritter "Million object spectrograph", Proc. SPIE 7018, Advanced Optical and Mechanical Technologies in Telescopes and Instrumentation, 70182R (23 July 2008); https://doi.org/10.1117/12.790244

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available