We would like to introduce to our readers the document “Beginner’s Guide to Choosing Binoculars and Telescopes” published by One-Minute Astronomer and Mintaka Publishing Inc. This document will review the basic concepts. A review of binoculars and telescopes, and finally a recommendation for several types of telescopes and accessories based on individual needs and abilities. I hope you choose a suitable device soon and that your skies are always clear!
You can see a lot of cool things in the night sky just with the naked eye. In the darkness, far from city lights, you can see about 2,000 stars, several star clusters, the hazy trails of nebulae where new stars are forming, and even one or two galaxies containing about 10 billion stars. Stars are located outside the Milky Way.
But most new astronomers want to see more. This means they will want to own a pair of binoculars or a telescope, or both. A pair of binoculars will allow you to observe around ten thousand stars and dozens of bright, “deep” objects such as star clusters, nebulae and galaxies. And even a simple telescope in your backyard can observe thousands of other fascinating objects…enough for a lifetime of fascinating observations and satisfying contemplation.
However, choosing a pair of binoculars or a telescope poses a significant challenge for beginning astronomers. There are hundreds of models available with all sorts of bewildering specifications and features. Many beginners end up choosing telescopes that are too big, too complicated, or too poor quality… to use. And many people eventually become frustrated with stargazing and give up.
This won’t happen to you. Because this guide will show you the basics of choosing a beginner telescope and a good pair of binoculars for observing the night sky. With this guide, you’ll be able to choose the right stargazing tools for your budget and personal situation, tools that will help you see thousands of beautiful and memorable celestial objects in just a few minutes. A small number of people have visible tags.
Before we dive into choosing good optics for stargazing, let’s review what you need to know about telescopes to help you understand the contents of this document. It may be a little difficult to start here, but once you understand these things, the rest of the material will become easier. In fact, most beginners think that the purpose of a telescope is to magnify objects, to make them appear larger. This is not true. So what is a telescope for?
The purpose of a telescope is to collect light.
A telescope uses spherical lenses or mirrors (called objectives) to collect light from distant objects and focus that light into an image. A larger lens will collect more light and produce a sharper, brighter image. The converging image formed by the objective of a telescope is magnified by a second, smaller lens called an eyepiece. As observers, we look through the eyepiece to see the magnified image of the lens. But an eyepiece uses a small lens or mirror that simply enlarges a blurry image.
Figure 1: Diagram of a simple telescope.
Therefore, while magnification is useful, it does not help you see more details in a telescope. Image detail and brightness all come from the amount of light collected by the lens. And it depends on the diameter of the lens, also called aperture. Just like a large jar collects more raindrops than a small jar, a large lens will collect more light than a small one.
Let’s take an example. Observe Jupiter with two telescopes, one with an objective diameter of 2 inches and the other of 4 inches, and choose the eyepiece of each telescope to give 100x (or 100x) magnification. So each image will appear with the same size.
With a telescope with a 2-inch aperture, Jupiter’s largest cloud bands will be visible but slightly blurred. And with the 4-inch telescope you see more structure and color, and smaller cloud bands are present that are not visible with the 2-inch telescope. The advantage of a larger telescope is that it collects more light, allowing us to see more detail than a smaller telescope with the same magnification.
Figure 2: Jupiter at 100x magnification in a 2-inch (left) and 4-inch (right) aperture telescope.
So a telescope that collects more light will provide better observations. Does this mean that choosing a telescope will be easy? Just choose the telescope with the largest objective lens possible?
Yes, but compromises will have to be made. Telescopes with larger apertures are more expensive, heavier, and in some cases more difficult to use than smaller telescopes. They produce a narrower view of the night sky than small telescopes. So you have to consider all these things.
But we are on the right track. We will return briefly to all these points. From there, just remember that the purpose of a telescope is to collect light, and the more light there is, the better the photos will be and the more enjoyable the observing experience will be. Before we delve deeper into telescopes, let’s talk about binoculars, the most complete and useful optical instrument for observing the night sky.
To be continued…
According to Hien Phan – VLTV
Nguồn: Beginner’s Guide to Choosing Binoculars and Telescopes for Stargazing