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Optical Engineering

Predictions of the SOFIA telescope seeing in flight
Author(s): George W. Sutton; John E. Pond
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Paper Abstract

The results of detailed predictions are presented for the wavelength dependence of the blur circle of the proposed Stratospheric Observatory for Infrared Astronomy (SOFIA), which will have a 2.5 m diameter telescope in an open cavity aft of the wing on a Boeing 747SP aircraft. The analysis uses wind tunnel measurements of the turbulent shear layer (Rose Engineering and Research, 1996), computer calculations of the telescope cavity shear layer organized air density fluctuations (Atwood, 1993) and extrapolation of the cavity optical effects of the Kuiper Airborne Observatory (KAO) (Sutton, 1992) based on the expected SOFIA cavity noise (Rose Engineering and Research, 1996). The results indicate a visible wavelength blur circle diameter of many arc seconds, which then raised the issue of the use of the visible spectrum for natural guide stars to obtain the long term pointing accuracy of 0.14 arcsec. Detailed calculations of SNR indicate there are a sufficient number of stars having adequate visible brightness to achieve this objective. Optical tests in a quiet transonic wind tunnel and independent calculations of the air density fluctuations in the telescope cavity would confirm this result.

Paper Details

Date Published: 1 November 1998
PDF: 6 pages
Opt. Eng. 37(11) doi: 10.1117/1.601874
Published in: Optical Engineering Volume 37, Issue 11
Show Author Affiliations
George W. Sutton, Aero Thermo Technology Inc (United States)
John E. Pond, Analysis & Applications Associates, Inc. (United States)

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