How To Determine The Tube Length For A Telescop. disk within the focal depth of the telescope (<0.030”) which indicates that the baseplate is within 0.0005” (60:1 lever arm ratio) of the ideal location. 3.5) If the baseplate is not. The resulting focal length can be calculated by multiplying the telescope’s focal length by the focal reducer’s multiplier. For example, a telescope with a focal.

In order to determine the tube length for a telescope, there are several factors to consider. The type of telescope and the intended use are the two most important. Telescopes come in a variety of types, including refractors, reflectors, and catadioptric designs. Each of these types will require different tube lengths for optimal performance. Additionally, the intended use of the telescope will also need to be taken into account.

The most common type of telescope is the refractor. Refractors have a tube length that is determined by the focal ratio. This is calculated by dividing the focal length by the aperture. For example, a telescope with a focal length of 1000mm and an aperture of 200mm would have a focal ratio of f/5. Generally, refractors with a focal ratio of f/6 or longer will require a tube length of at least 1000mm.

Reflectors, such as Newtonian and Dobsonian telescopes, typically require a longer tube length than refractors. The tube length is determined by the desired field of view, or the amount of sky visible when looking through the telescope. A larger field of view requires a longer tube length, and a shorter tube length implies a smaller field of view. For example, a Newtonian telescope with a focal length of 1000mm and a field of view of 1° would require a tube length of at least 1300mm.

Catadioptric telescopes, also known as Schmidt-Cassegrain or Maksutov-Cassegrain telescopes, are usually quite compact and require a much shorter tube length than refractors and reflectors. These telescopes are usually designed with a fixed focal length and have a focal ratio of f/10, which requires a tube length of around 500mm.

The intended use of the telescope should also be taken into account when determining the tube length. For example, a telescope used for astrophotography will require a longer tube length than one used for visual observations. This is because astrophotography requires a longer focal length in order to capture finer details in the image. Generally, a telescope used for astrophotography should have a tube length of at least 1500mm.

Once the type of telescope and intended use have been determined, the tube length can be calculated. If the telescope is a refractor, the focal ratio can be used to calculate the tube length. For reflectors, the field of view and focal length can be used. Catadioptric telescopes usually have a fixed focal ratio of f/10, which requires a tube length of around 500mm. For astrophotography, a tube length of at least 1500mm is recommended.

In conclusion, the tube length for a telescope is determined by the type of telescope and the intended use. Refractors require a tube length that is determined by the focal ratio, while reflectors and catadioptric telescopes require a tube length that is determined by the field of view and focal length. For astrophotography, a tube length of at least 1500mm is recommended.

## Telescope Basics 2 (of 6): Learn to calculate magnification for a telescope/understand focal ratios

Hosted by David Fuller of "Eyes on the Sky," this video discusses the basics of telescope magnification and focal ratio. Each concept is covered, guiding the viewer through how to calculate magnification of a telescope and eyepiece combination, and how to determine the focal ratio of a given telescope. An excellent primer for anyone wanting to understand more about telescopes. #withcaptions

tube the minimum height and adapter is 1.25 µ. In this configuration the distance from secondary mirror to focal plane in a 15 µ O.D. tube would have been 9.0625 µ (with. , How To Determine The Tube Length For A Telescop.