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Celestial navigation uses “sights”, or timed angular measurements, taken typically between a celestial body (e.g. the Sun, the Moon, a planet, or a star) and the visible horizon.
What are the best sextants?
In this monetary respect only, we would rate the ASTRA IIIB sextant highest, and the Tamaya sextants lowest in value for the metal sextants. The Davis Mark 15 is the best in value for the plastic models.
How are constellations used in modern astronomy?
Modern astronomers still use constellations to divide the sky into different regions (Fig. 2). It may surprise you to learn that professionals don’t use constellations to locate targets; instead, they use celestial coordinates (which resemble longitude and latitude used on Earth).
Can I buy a sextant?
Purchase only from someone you know and trust, or a reputable dealer. You will find that today’s low cost metal sextants are very competitive with expensive used ones. To avoid worries about bent arcs, serious navigators traditionally buy their sextants new. Common wisdom is that a used sextant is probably bent.
How much does a good sextant cost?
Prices vary significantly but you can find a good aluminum sextant like Astra IIIb for anywhere between $250 to $300. The question for a used sextant is not how old it is, how well it has been taken care of and whether it actually works.
compass, in navigation or surveying, the primary device for direction-finding on the surface of the Earth. Compasses may operate on magnetic or gyroscopic principles or by determining the direction of the Sun or a star.
An experienced celestial navigator, on the other hand, can adjust technique to accommodate the shifting errors. Generally, metal sextants at all price points also have better-quality optics (mirrors, telescopes, and shades), again making sight taking easier and more consistent.
What is the best sextant for beginners?
Primarily for this reason, Gebhart of Celestaire usually recommends that the novice celestial navigator opt for a metal sextant (this is actually contrary to the way many approach buying a sextant, thinking that a plastic sextant is a good “beginner” sextant).
What are the disadvantages of using a sextant?
Plastic sextants commonly exhibit errors in excess of 5 minutes, even when great care is exercised. Although this is sufficient to make landfalls; precision navigation is difficult, and student progress may be retarded. The size of the mirrors on sextants generally vary directly with the quality of the instrument.
Should I buy a sextant or a horizon mirror?
In general, people on stable platforms such as large ships tend to favor the traditional horizon mirror while those on yachts tend to favor the whole horizon mirror. Sextant lighting is the least needed feature on a sextant, since a flashlight should normally be available in any event for recording observations.