If stargazing is your hobby, and you are planning to get a new telescope for your personal use, you should have a basic idea on telescopes. Telescopes come in various sizes and in different price ranges. However there are 3 basic types of telescope that you should know before taking the plunge. If you are asking what is the best telescope, the answer can greatly vary depending on what you need and what you can afford.
Telescopes can be widely categorized into three categories as the following.
The most common type of telescope with a very basic principle is a refractor. In a refractor, the eyepiece is at the end of the OTA. It uses lenses to gather light. These lenses are made from special glasses to reduce aberrations. The optical system is arranged in a linear manner. This eliminates the need to realign the telescope again and again. Refractors are also low on maintenance. They are great to view Moon’s craters, Saturn’s rings and few major Jupiter’s satellites.
Refractors however, tend to get bulkier and pricier with increase in aperture. In fact, the price hike is rather abrupt with increase in aperture. Their burly structure impairs mobility. This is why they are not very apt for personal use.
Reflectors or reflecting telescopes work by gathering light using a mirror at the back end of the OTA. Newtonians and Dobsonians are the most common types of reflectors available. Dobsonians can be disassembled which makes them portable. Price of a reflector for a certain aperture is generally lesser than a refractor of the same aperture. Their optical tubes too are comparatively smaller. Reflecting telescopes are great to view galaxies and other deep-sky objects.
But reflectors are higher on maintenance than refractors. The optical pieces tend to gather dust and need to be cleaned regularly. Reflectors also lose focus and needs realignment every time.
Compound telescopes are also called catadiotropics. These telescopes use a combination of lenses and mirrors, thus offering the best of two worlds – refractors and reflectors. Their optical tubes are compact yet have long focal lengths. Two popular designs of catadiotropics are Schmidt-Cassegrains and Maksutov-Cassegrains. These are versatile, compact, portable and hence the most popular. You should opt for a catadiotropic for personal use. The best telescopes in this category include Meade Instruments LX90-ACF, Celestron NexStar Evolution 9.25, and Orion 9825 Apex 127mm.
There is an advanced category of telescopes other than the above three, known as go-to telescopes.
What are Go-To Telescopes?
Go-to telescopes are compound telescopes with advanced, motorized mounts. The hand control of the telescope has an inbuilt mini-computer automatically aligns the scope on giving certain inputs like date, time and place. These inputs then help the scope to track various stellar and planetary movements. However go-to telescopes are targeted towards the more professional stargazers. These are complicated for beginners, because the setup takes a lot of time and practice. They also bear hefty price tags, making them not a very popular choice among buyers.