Disassembling a home-made Refractor Telescope

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1. Optical Tube

A 680-690 mm PVC pipe, 48mm wide completely painted black was used as the optical tube.

Fig. 1 The Tube
2. The Clamp

The clamp was custom made with threads at bottom to screw it on to the tripod.

Fig. 2 The Clamp

3. Objective Lens

It is an achromatic convex lens (uses clever methods to avoid chromatic aberration) with aperture 50 mm and focal length 700mm. It uses combination of crown glass and flint glass to get rid of chromatic aberration.


Fig. 3 a) The Lens b) Visible Boundary of crown and flint glass

4. Lens Housing

The objective lens is placed in a bucket like holder which holds it in front of the optical tube.
Fig. 4 The Housing a) Side View
 b) Top View

5.  Diagonal

It is a mirror at an angle of 45 degrees that reflects light from the objective by 90 degrees.
By redirecting optical path to the side of the telescope, the diagonal mirror allows for more comfortable viewing. Without it, the observer would need to position themselves awkwardly, often at the end of the telescope tube, to see the resultant focused image.


Fig. 5 The diagonal mirror is housed within this; the screw is used to fix it on the telescope

6. Focuser

The focuser allows you to adjust the position of eyepiece or camera along the optical axis of telescope. This adjustment is essential since it ensures that the image formed by  telescope's optics comes into precise focus onto eyepiece or camera sensor. Without a focuser, it would be challenging to achieve this precision, resulting in blurry images.


Fig. 7 The dial is moved to adjust the focus

7. Eyepiece

The eyepiece comes in different focal lengths and coatings, it'll be discussed in detail in  another post. It is placed one top of the diagonal and increases magnification of targeted body. Eyepieces come in different configurations- Huygens, Ramsden, Kellner, Plossl etc. 
Eyepiece used here has Ramsden configuration.



             Fig. 8 a) The coating and lens housing  b) Inside view of Ramsden eyepiece 

8. Tripod

The Tripod has a screw on top where the clamp gets mounted along with the optical tube, keeping the scope balanced and stable.

Fig. 9   The Tripod with the screw 

9. Solar Filter

The sun must not be directly seen with your eyes (retina will be damaged) hence a solar filter is used.
There are 2 types of filters- Aperture solar filters and eyepiece solar filters
Aperture solar filters are highly recommended for viewing sun, they block most of Sun's rays and prevent heating of optical tube.
Some telescopes come with eyepiece solar filters, though they do not block radiation entering scope's body,  resulting in heating of scope and cracking of filter (highly dangerous). AVOID PURCHASING THIS TYPE OF FILTER.

Fig. 10 Solar Filter 

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