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Subject: Two Meade Alignments.
From: James W. Burrows
Reply To: mapug@shore.net
Date: Tue Feb 27 00:24:35 1996

PURPOSE: evaluate the "whole sky" accuracy of Meade's 2-star ALTAZ
alignment.

SETUP: Meade 8" f/6.3 LX200, Orion 12.5 mm reticle eyepiece (1.2'
guidance box), rough tripod leveling (ca. 1 deg), 0-star alignment
(cycle power with OTA level and pointing approx. S) before each test.
The following azimuths assume N=0, the errors are radial, and reported
in arc-minutes.

TEST 1: 2-star align using ALKAID and REGULUS (70 deg azimuth
separation), sync on BETELGEUSE (90 deg further azimuth separation),
then find pointing error on the "other side" of the sky.

AZM ALT ERR'
45 27 - Meade align, star 1, ALKAID
114 36 - 2, REGULUS
202 48 12.6 = error before SYNC at BETELGEUSE
293 28 4.8 = error observation at MIRACH (bet And, SAO 54471)

TEST 2: Align using ALKAID and BETELGEUSE (160 deg azimuth separation),
sync on REGULUS (between), then find pointing error at the same star as
TEST 1.

AZM ALT ERR'
46 28 - Meade align, star 1, ALKAID
205 47 - 2, BETELGEUSE
117 38 4.9 = error before SYNC at REGULUS
295 26 11.7 = error observation at MIRACH (bet And, SAO 54471)

DISCUSSION: I'm surprised that the final error in TEST 2 is more than
twice that of TEST 1. The alignment stars in TEST 2 were much more
widely separated, so the alignment "should" have been better. It may be
that the smaller azimuth difference between sync star and test star in
TEST 1 is more important than expected quality of the alignment.

Jim Burrows