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Subject: [M]: 1-star followed by 2-star.
From: James W. Burrows
Reply To: mapug@shore.net
Date: Tue Dec 17 23:57:07 1996

The accuracy of 2-star altaz alignment vs. 1-star followed by 2-star is
not statistically significant.

I tried it last night (Seattle's first clear night in 13 days) using Deneb
(azm=334, alt=8 (low)) and Sirius (171,25), then RMSed the radial error at
3 other stars (ca. 120 degrees azimuth apart). Got 1.82 mrad for 2-star,
1.80 for 1-star + 2-star.

The conclusion is that the refraction correction procedure simply isn't
called in the 2-star alignment algorithm.

-- Jim Burrows: (206)244-2933, fax: -0294
-- E-mail: burrjaw@halcyon.com
-- Seattle: WGS84 lat 0.828547, long -2.135692 (rad)