The Astra IIIB is an all-aluminium sextant, and when introduced quickly became popular wooden box, with an adjustment key, test certificate, and user manual. Download Astra iiib sextant manual: ?file=astra+ iiib+sextant+manual Astra III Professional Sextant. This sextant. The Astra IIIB is made by the Changzhou Celestaire Instrument Co. in China, with whom and has instructions for easy installation. We are impressed with the.

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It is also of benefit when taking horizontal sextant angles, as you can identify the landmarks and the magnification is not needed.

We recommend this instrument because it has more than adequate quality for the job and is at a reasonable price. Random units have been tested iijb us and several professional navigators, with results that rival the most expensive German and Japanese models. Since then its specification has steadily been improved, and it continues to offer good value for money.

Astra IIIB sextant

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.

Other differences are that it has an improved handle design, and the light can be dimmed for astrra viewing faint stars.

Astra sextants are manufactured in China as a brand name for Celestaire. The sight scope is 3. The sextant is fairly light with its aluminium frame and plastic handle. On the other hand, essentially any metal sextant will do the job if it has not been damaged. We are impressed with the degree to which each component of the sextant is tested. Practice Artificial Horizon This bubble horizon replaces the normal scope on the sextant, and allows you to take a sight without being able to view the horizon.


Bargains on used instruments still exist. Sight accuracy is claimed to be about 2′. We recommend the traditional mirror as opposed to so-called “full view” models, and the deluxe version, which has the larger mirrors.

This sextant is to the same design as the popular IIIB, but the primary change is that it has a bronze arc fused to an aluminium frame, similar to the Tamaya sextants.

Astra IIIB Sextant

The index mirror is rectangular in shape and is the same size as used more expensive sextants. Aluminum alloy is not new to sextant construction.

Xstra included new box, improved lighting, and larger index mirror. Rubber Eyecap This rubber eyecap can be used with the scope, sight tube or artificial horizon. The sextant comes in a varnished wooden box, with an adjustment key, test certificate, and user manual. It can take the optional rubber eye cap.

See discussion of sextant mirror types in the FAQs on our celestial nav home study course. The sextant comes with the traditional, all-purpose “4×40” telescope. Even in nautical matters, some things change.

This bubble horizon replaces the normal scope on the sextant, and allows you to take a sight without being able to view the horizon. An optional additional 7×35 scope is available to enhance sun and moon sights and improve index correction measurements.

It is made of blackplastic, and has a matt black interior to minimise refletions.

These days, it is difficult to justify paying more when you can buy this sextant plus two GPS units for the price of most other sextants alone. This shape allows more aspect of the mirror to be available for high angle sights.


It comes mounted in a rectangular frame and has instructions for easy installation. Yet, we know several professional navigators who prefer the ASTRA IIIB merely because they can leave their expensive models at home without sacrificing noticeable accuracy.

Also, and probably more importantly, many people find that the extra weight makes the sextant iiib when taking a sight. This means the sextant does not have to be held as steady for them.

awtra In use, you hold the sextant so that the horizon hairline on the right side of the scope lines up with the bubble on the left. There are 4 shades for the index mirror, and 3 for the horizon mirror. An index mirror upgrade kit is available for older models having smaller, round, index mirrors. If you are a beginner, the much larger field of view makes it easier to identify the stars through the sextant; and asta the boat is moving a lot a sight tube makes it easier to keep the body in view.

It has long been used by many manufacturers for lightweight versions of their heavier brass astga bronze sextants in order to reduce arm fatigue and unsteadiness among infrequent users. Its popularity has spread throughout the rest of the world as well, making it the iiin most recognized and supported sextant worldwide.

Never before has such a high quality, accurate metal sextant been available at such a low price. The sextant is electrically lighted by an LED on the arc and drum.