Astra IIIB Deluxe Sextant with Traditional Mirror 0502D
The Astra IIIB Sextant has revolutionized celestial navigation. Never before has such a high quality, accurate metal sextant been available at such a price.
Over 26,000 of the IIIB model have been sold in the US since being introduced in 1986; far more than any other serious sextant. Its popularity has spread through the rest of the world, making it the most recognized (and supported) Sextant worldwide.
Its low price, excellent optics, makes it the perfect selection for beginners. Yet, Celestaire know of several professional navigators who prefer the Astra IIIB merely because they can leave their expensive models at home without sacrificing any noticeable accuracy.
The frame is made from a lightweight aluminum alloy which resists corrosion. Aluminum alloy is not new to sextant construction. It has long been used by many manufacturers for lightweight versions of their heavier brass or bronze sextants in order to reduce arm fatigue and unsteadiness among infrequent users. 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 lightweight 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 on more expensive Sextants. This shape allows more aspect of the mirror to be available for high angle sights. This means the Sextant does not have to be held as steady for them.
We are impressed with the degree to which each component of the sextant is tested. Each mirror and shade glass is tested for perfect flatness by the Fresnel diffraction pattern method. The Sextants are assembled and tested in a clean, professional, environment. Random units have been tested by Celestaire and several professional navigators, with results that rival the most expensive German and Japanese models.
The ability to quickly and economically change the type of horizon mirror is an attraction of this sextant to many navigators. This is because whole horizon mirrors are generally preferred by beginners who later may wish to change to a traditional mirror as proficiency is attained.
Maintainability is appreciated by schools and other groups who because of heavy usage need inexpensive replacement parts due to the threat of student mishandling.
The Sextant has LED lighting of the Arc and Drum powered by two standard size AA batteries (not included) which install in the handle.
It comes in a varnished wooden case, with an instruction book, certificate of accuracy, and adjusting wrench.
Case external dimensions are 6.5"x 13" x 11". It includes a 3.5 x 40 Monocular telescope as standard equipment.
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