The Astra Sextant Allview & Light frame is made from lightweight aluminium alloy which resists corrosion and comes complete with “whole horizon mirror”. The sextant is electrically lighted by an LED on the arc and drum.
The Astra IIIB is considered by many to be the easiest sextant to use. Its light weight and excellent balance makes it a pleasure to hold and makes sights easier to take under dynamic weather and sea conditions.
Even reading the sextant is easier under low light conditions by having white degree marks against a black background as opposed to scribe marks on a brass arc.
The index mirror is rectangular in shape and is the same size as used in more expensive sextants. This shape allows more of the mirror to be available for high angle sights, meaning the sextant does not have to be held completely steady.