A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2015 Nov 26, 13:37 -0800
My dock neighbor let me have a few days with his Freiberger Sirius sextant to test and calibrate. This sextant has front silvered mirrors, 4x40mm scope, and an arc error that is rated at better than 0.2' from 0° to 120°. I found that the micrometer drum had excessive drag. This was remedied with WD 40 followed by light machine oil. Smooth as silk now. Index error was out of the box at zero. After two days of observations the index error was still zero (nice!). I like the mirror adjustment screws which have an extra collar that snugs things up after adjustment. Filters, scope, and mirrors are excellent. The aluminum construction is solid and about a pound lighter than a Plath. All LOP observations of Sun, Moon, Venus, and Sirius came in better than 1' using an artificial horizon. I give the sextant an A- overall and is one of the better value buys on the used market.
See attached pic of micrometer drum showing open slot where to spray WD 40.