Calculate Tube Length Of Telescope. Figure 1. The minimum tube diameter is determined b y MTD = 2 * D2E * Tan (TF / 2) + D + 0.5 where the d istance (D2E) is from the primary mirror face to the end of the telescope. There is no formula to calculate the focal length of your telescope. It is a fixed measure that is unique to your telescope and can be found on a label usually.

Calculating the tube length of a telescope is an important part of its design. Knowing the tube length of a telescope helps to determine its strength and the type of images it can produce. Here’s how to calculate the tube length of a telescope.

- Determine the focal length of the telescope. This is the distance from the primary objective, or the lens at the front of the telescope, to the point where the image appears to be the same size as the object being viewed.
- Find the focal ratio of the telescope. This is calculated by dividing the focal length by the diameter of the primary objective. For example, a telescope with a 500 mm focal length and a 100 mm objective has a focal ratio of 5.
- Calculate the tube length by multiplying the focal length by the focal ratio. In the example, the tube length would be 500 x 5 = 2,500 mm.

The tube length of a telescope is important to consider when making a purchase. A longer tube can house a larger primary objective, which will produce brighter and sharper images. However, a longer tube also makes the telescope heavier and more difficult to transport and set up. With the information above, you should be able to calculate the tube length of a telescope and make an informed purchasing decision.

It is important to remember that the tube length of a telescope does not determine the magnification of the telescope. The magnification is determined by the eyepiece and the focal length of the telescope. If you need help understanding the relationship between focal length and magnification, you can consult a telescope expert or read up on the subject.

By taking the time to calculate the tube length of a telescope, you can be sure that you are making a wise purchase. Knowing the tube length can help you choose the right telescope for your needs and ensure that you get the best performance possible.

## Optics Optical instruments Astronomical telescope Calculations

This video contains three examples about calculations involved in astronomical telescopes, and two exercises. The last one requires you to make some research about eye ring in telescopes. Feel free to leave a comment, even when you need me to make a solution for the exercise, or any other videos you want me to make.

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. 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. Formula Used. Length of Telescope = Focal Length of Objective+ (Least Distance of Distinct Vision*Focal Length of Eyepiece)/ (Least Distance of Distinct Vision+Focal., Calculate Tube Length Of Telescope.