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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The ebook must be read from a Windows PC. 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. Its low price, excellent optics, and choice of horizon mirrors and other accessories makes it the perfect selection for manuzl. It has a good sized index mirror, and this index mirror is now silvered on the front face for maximum accuracy.
It comes mounted in a rectangular frame and has instructions for easy installation. This sextant is to the same design astrq the popular IIIB, but the primary change mankal that it has a bronze arc fused to an aluminium frame, similar to the Tamaya sextants. You then change the sextant angle to bring the body down to the hairline. 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.
Sextant Astra IIIB
Other differences are that it has an improved handle design, and the light can be dimmed for when viewing faint stars. It mmanual also been reviewed as the best source available for how to use metal sextants.
This aluminum-alloy instrument at some 2. Even in nautical matters, some things change. The sextants are assembled and tested in a clean, professional, environment.
Its popularity has spread throughout the rest of the astrra as well, making it the the most recognized and supported sextant worldwide. One can always use the price of this new one as a reference for evaluating the price of such an opportunity. If you are a beginner, the much larger field of view makes it easier to identify the stars through the sextant; and if the boat is moving a lot a sight tube makes it easier to keep maual body in view.
Note that aluminum alloy sextants are not unique to this Chinese manufacturer, even the makers of the expensive brass versions offer aluminum alloy models, sometimes even more expensive than their brass models. Its light weight and excellent balance makes it a pleasure to hold and makes sights easier to take under dynamic weather and sea conditions. This means the sextant does not have to be held as steady for them. This shape allows more aspect of the mirror to be available for high angle sights.
WinAstro Astro navigation on your PC. On the other hand, essentially any metal sextant will do the job if it has not been damaged.
Bargains on used instruments still exist. Astra sextants are manufactured in China as a brand name for Celestaire. Whilst the magnification obtained through having a scope instead of a plain sight tube can make your sights more accurate, there are times when a plain sight tube is an advantage.
The index mirror is rectangular in shape and is the same size as used more expensive sextants.
It is also of benefit when taking horizontal sextant angles, as you can identify the landmarks and the magnification is not needed. It astrz 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.
Sextant : Astra IIIB sextant
The Astra optics are excellent and the instrument has a good feel to it. The sextant is electrically lighted by an LED on the arc and drum. It can take the optional rubber eye cap.
We also carry a full line of Davis plastic sextants.
We recommend the traditional mirror as opposed to so-called “full ashra models, and the deluxe version, which has the larger mirrors. The sextant comes with the traditional, all-purpose “4×40” telescope. This bubble horizon replaces the normal scope on the sextant, and allows you to take a sight without being able to view the horizon.
The sight scope is 3. An index mirror upgrade kit is available for older models having smaller, round, index mirrors.
Slip-on Rubber Eyecup for Scope. Also, and probably more importantly, many people find that the extra weight makes the sextant steadier when taking a sight.
Please do not be misled by the title. The Astra is dependable and more than accurate enough for the job. The sextant is fairly light with its aluminium frame and plastic handle.
Rubber Eyecap This rubber eyecap can be used with the scope, sight tube or artificial horizon. Beschrijving Metalen halfzicht Sextant in traditionele houten kist.
When you install the artificial horizon, you calibrate it, and include this offset in your sight corrections.
Since then its specification has steadily been improved, and it continues to offer good value for money. Never before has such a high quality, accurate metal sextant been available at such a low price.
Astra IIIB sextant
Aluminum alloy is not new to sextant construction. They offer good value for money metal sextants – not as good as Freiberger and other high end sextants, but considerably more iib than plastic ones. There are 4 shades for the index mirror, and 3 for the horizon mirror.
Upgrades included new box, improved lighting, and larger index mirror.
Construction Details The frame is made from lightweight aluminum alloy which resists corrosion. For example, each mirror and shade glass is tested for perfect flatness by the Fresnel diffraction pattern method. An optional additional 7×35 scope is available to enhance sun and moon sights and improve index correction measurements.