A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Hewitt Schlereth
Date: 2014 Aug 8, 21:46 -0700
On Aug 8, 2014, at 8:11 PM, "Greg Rudzinski" <NoReply_Rudzinski@fer3.com> wrote:
This evening from Yonkers N.Y. I have taken 6 observations of the Moon in an artificial horizon using an Ebbco plastic sextant. Adjusting the index and horizon mirrors was on the difficult side using a small hex wrench. Determining index error was also difficult because of an unexpected large spread in index error values (5'). I went with the average which was 3' on the arc. The scope which has plastic lenses worked better than expected showing detailed features on the Moon. The most serious issue were 2 ghost images showing along with the bright reflected image. This didn't seem to affect function though. The spread of 6 intercepts was 5' with an average of 1.3' toward. Performance is well behind my Tamaya and Plath metal sextants which regularly have spreads of no more than 1' for a set of observations when using an artificial horizon. Never the less the plastic Ebbco finds a place in my sextant inventory as a good enough , compact, light, and inexpensive sextant. $35 should bag a good one on Ebay.