Description
The Celestaire 7×35 Prism Telescope is a high-precision telescope designed specifically for use with a sextant for astronomical navigation. With higher magnification than standard sextant telescopes, this telescope provides a clearer view of both celestial bodies and the horizon, which can contribute to more precise observations during sextant navigation.
A higher magnification telescope makes the diameter of the sun appear larger in the field of view. This makes it easier for the navigator to determine the exact point at which the edge of the sun touches the horizon – an important aspect of accurate sextant observations. The increased magnification also makes the horizon clearer when it is far away, as it often is when observations are taken from ships at sea.
A more powerful telescope can also be useful for more advanced astro-navigation techniques, such as measuring lunar distances (lunars). This method uses the position of the moon in relation to stars, planets or the sun to determine time. Such observations require very high precision, and a telescope with a higher magnification can make it easier to achieve accurate measurements.
An important feature of a good sextant telescope is that the mounting fork – often called a “fork” or “rising piece” – is completely perpendicular to the optical axis of the telescope. Even small deviations can cause measurement errors when observing at high angles. On the Celestaire 7×35 Prism Telescope, the mounting fork is cast as an integral part of the aluminum body. This ensures correct geometry and high precision, and eliminates errors that can occur on telescopes where the mount is screwed on afterwards.
The telescope has high-quality optics and is specially designed for use with a sextant. It provides a clear and stable image, while the construction is robust enough for use at sea.
The Celestaire 7×35 Prism Telescope fits several modern metal sextants, including Celestaire Astra IIIB, Astra III Professional, as well as sextants from Cassens & Plath, C. Plath and Tamaya.
This is a useful accessory for navigators who want better optics and higher precision for sextant sailing and advanced astronomical navigation.
