NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2012 May 4, 11:38 -0700
To continue daytime Venus dip short trials I have dusted off my Cassens and Plath whole horizon with a 4 x 40 mm scope. First index error was checked using the Sun. Because the Cassens and Plath has an index adjuster on the micrometer drum it is a simple process to get zero index error. First the Sun's diameter is measured on the arc then the micrometer drum is adjusted to the almanac diameter. I adjusted to 31.6' then measured off the arc and got 31.6' to confirm zero error. Pre-calculated altitude and azimuth had me looking in about the same spot as yesterdays trials. Picking up Venus using the 4 x 40 mm was more difficult than with the 7 x 35 mm scope. Also the whole horizon made things tougher as well but with patience five observations were made yielding a spread of 0.7' and an average intercept of 0.3' A. This was a litte better than the Tamaya performance yesterday. Another little thing that was noticed using the 4 x 40 mm scope is that Venus appeared as a dot and not as an oval as seen in the 7 x 35 mm scope. Results aside I was very pleased just to be able to see Venus with 4 power optics and a whole horizon :)
Greg Rudzinski
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