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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Astra IIIB sextant
ioib 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. Slip-on Rubber Eyecup for Scope. It is also been reviewed as the best source available for how to use metal sextants.
Its light weight and excellent balance makes it a pleasure to hold and makes sights easier to take under dynamic weather and sea conditions. The sextant comes with the traditional, manal “4×40” telescope. We are impressed with the degree to which each component of the sextant is tested. 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 the body in view.
Never before has such a high quality, accurate metal sextant been available at such a low price. Please do not be misled by the title. WinAstro Astro navigation on your PC. Since then its specification has steadily been improved, and it continues to offer good value for money. On the other hand, essentially any metal sextant will do the job if it has not been damaged.
They offer good value for money metal sextants – not as good as Freiberger and other high end sextants, but considerably more accurate than plastic ones.
Astra IIIB Sextant
The sextant is electrically lighted by an LED on the arc and drum. We recommend this instrument because it has more than adequate quality for the job and is at a reasonable price. It can take the optional rubber eye cap. 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. Sight accuracy is claimed to be about 2′. The Astra is dependable and more than accurate enough for the job.
For example, each mirror and shade glass is tested for perfect flatness by the Fresnel diffraction pattern method. One can always use the price of this new one as a reference for evaluating the price of such an opportunity. This means the sextant does not have to be held as steady for them.
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 manuaal is an advantage. It is also of benefit when taking horizontal sextant angles, as you can identify the landmarks and the magnification is not needed. Even in nautical matters, some things change. Random units have been tested by us and several professional navigators, with results that rival the most expensive German and Japanese models.
Instruction manual for Astra III-B Marine – Search Yale Digital Content
When you install the artificial horizon, you calibrate it, and include this offset in your sight corrections. It has long been used by many manufacturers for lightweight mznual of their heavier brass or bronze sextants in order to reduce arm fatigue and unsteadiness among infrequent users.
The iilb scope is 3. This bubble horizon replaces the normal scope on the sextant, and allows you to take a sight without being able to view the horizon. 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.
There are 4 shades for the index mirror, and 3 for the horizon mirror. Practice Artificial Horizon This bubble horizon majual the normal scope on the sextant, and allows you to take a sight asttra being able to view the horizon. Bargains on used instruments still exist. Astra sextants are manufactured in China as a brand name for Celestaire.
An index mirror upgrade kit is available for older models having smaller, round, index mirrors.
Kiib optional additional 7×35 scope is available to enhance sun and moon sights and improve index correction measurements. A serial number is provided at the time of sextant purchase. Its low price, excellent optics, and choice of horizon mirrors and other accessories makes it the perfect selection for beginners.
You then change the sextant angle to bring the body down to the hairline. It is made of blackplastic, and has a matt black interior to minimise refletions. Upgrades included new box, improved lighting, and larger index mirror. It comes mounted in a rectangular frame and has instructions for easy installation.
Other differences are that it has an improved handle design, and the light can be dimmed for when viewing faint stars.