DIY Telescope Making Series

DIY Telescope making is a fascinating and rewarding hobby that allows you to explore the universe and observe celestial objects. With the help of modern technology and the internet, it is now easier than ever to learn how to make your own telescope. In this article, we will provide a detailed guide to making a homemade astronomical telescope from scratch with a video tutorial covering all the steps and parts needed to create a focuser, tripod stand, equatorial mount, AZ mount, reflector telescope, and refractor telescope.

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The Science of Astronomical Telescopes: A Practical Overview

1. Magnification

Magnification is the ability of a telescope to enlarge the image of an object. It is determined by the ratio of the focal length of the objective lens (or mirror) to the focal length of the eyepiece.

M=F,eyepiece/​Fobjective​​

• M: Magnification
• F objective: Focal length of the objective lens/mirror
• 𝐹 eyepiece: Focal length of the eyepiece

Example: If the objective lens has a focal length of 900 mm and the eyepiece has a focal length of 10 mm, the magnification will be: M =900/10=90

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2. Aperture

The aperture is the diameter of the objective lens or mirror. It determines the amount of light the telescope can gather. A larger aperture allows more light to enter, enabling the telescope to observe fainter objects and achieve better resolution. Aperture=Diameter of the Objective

• Typical apertures range from a few centimeters for amateur telescopes to several meters for professional ones.

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3. Focal Length

The focal length is the distance between the objective lens (or mirror) and the point where the light rays converge to form a sharp image. F=Distance from Objective to Focal Plane

F=Distance from Objective to Focal Plane

A longer focal length generally results in higher magnification for a given eyepiece but narrows the field of view.

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4. Focal Ratio (f/Ratio)

The focal ratio, also known as the 𝑓 / f/ number, is the ratio of the telescope's focal length to its aperture.

• f/Ratio=DF​

• F: Focal length of the objective
• D: Diameter of the aperture

A smaller 𝑓 / f/ ratio ( 𝑓 / 4 f/4 to 𝑓 / 6 f/6) provides a wider field of view and is suitable for deep-sky observations. Larger 𝑓 / f/ ratios ( 𝑓 / 10 f/10 to 𝑓 / 15 f/15) are better for observing planets and the Moon.

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5. Field of View (FoV)

The field of view is the area of the sky visible through the telescope. It depends on the magnification and the eyepiece used.

V (degrees)= M Apparent FoV of Eyepiece ​

• A lower magnification gives a wider field of view.

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6. Resolving Power

Resolving power determines the telescope's ability to distinguish two close objects. It depends on the aperture and is calculated using the Dawes’ Limit

Resolution (arcseconds)= D 116 ​

• D: Aperture in millimeters
• Smaller values indicate better resolution.

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7. Types of Telescopes

There are three main types of astronomical telescopes:

• Refracting Telescopes: Use lenses to gather and focus light.
• Reflecting Telescopes: Use mirrors to gather and focus light.
• Catadioptric Telescopes: Combine lenses and mirrors.

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Materials and components for DIY Telescope.

The materials required for making a telescope will depend on the type of telescope you wish to create. However, here are some general materials that are used in most telescope designs:

• A primary mirror or lens
• Secondary mirror
• Focuser
• Eyepiece
• Tripod Stand
• Equatorial or AZ mount
• Telescope tube
• Finder scope
• Various hardware such as screws, bolts, and washers
• Rack and pinion gear

In this article, we will cover all parts of making telescopes

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Part 1: Making a Focuser for DIY Telescope

The first step in making a telescope is to create a focuser. A focuser is a device that allows you to adjust the focus of your telescope. In this tutorial, we will use a basic rack-and-pinion focuser.

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Video Tutorial of DIY Focuser

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Part 2: Making an AZ Mount

The next part is to create a tripod stand for your telescope. The tripod stand provides stability and support for the telescope. You can use wood or metal for this part, depending on your preference.

An AZ mount, also known as an Alt-Azimuth mount, is another type of mount that is easier to construct than an equatorial mount. This mount allows you to move your telescope up and down and left to right. This type of mount is perfect for observing objects in the sky.

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Part 3: Making a Telescope D50mm F600mm

A refractor telescope uses lenses to bend and focus light. This type of telescope is more difficult to construct than a reflector telescope, but it offers superior image quality.

Downloads:

Baffle Template:

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Part 4: Homemade D90F900mm Astronomical Telescope | DIY Refractor Telescope | Step-by-Step video tutorial.

Homemade D90 F900mm Astronomical Telescope template downloads

Baffle for 50mm 600mm

Why baffle is so important in telescopes?

A baffle is an important component in a telescope design, and it serves several essential purposes:

1. Minimizing Stray Light: One of the primary functions of a baffle in a telescope is to reduce or eliminate stray light from entering the optical system. Stray light can degrade the quality of the image by creating unwanted reflections and reducing contrast. By using baffles strategically placed within the telescope tube, you can prevent light from unwanted sources (like nearby streetlights or the moon) from entering the telescope's optics.
2. Improving Contrast: Stray light can scatter within the optical system, leading to reduced contrast in the observed image. Baffles help maintain high contrast by blocking off-axis light that would otherwise interfere with the desired image.
3. Enhancing Image Quality: Baffles also play a role in improving the overall image quality. By minimizing the effects of stray light and preventing it from reaching the telescope's focal plane, baffles help ensure that the image seen through the eyepiece or captured by imaging sensors is as clear and sharp as possible.
4. Reducing Glare: In certain observing conditions, such as when viewing a bright object like the Moon or a planet, glare can be a problem. Baffles help reduce glare by preventing excessive light from entering the telescope's optical path and overwhelming the observer.
5. Suppressing Ghosting and Flare: Baffles can also help suppress optical artifacts like ghosting and flare that can occur when internal reflections within the telescope tube bounce off optical surfaces. By controlling the path of light within the telescope, baffles can minimize these unwanted optical effects.

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DIY Telescope Diagonal, How To make Diagonal.

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Downloads:

• Baffle
• Focuser
• D50mm F600mm telescope template
• Focuser SVG/DXF files (ScienceStore.pk)
• Baffle for D90mm F900 mm telescope

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Making of 6-inch Reflector Telescope (Video Tutorial)

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What can you see with this telescope? see this video.

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Our previous blog posts and articles about DIY Telescope

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