As a beginner how to choose a telescope is difficult tusk. So here is an article can help you choosing a best telescope.
A telescope is not a small investment. It is important to take your time before choosing your first telescope. Certain factors are worth considering before you make a decision. This ensures that the telescope you end up buying will be according to your need and budget.
There are some questions you need to ask yourself before considering a telescope. What night sky objects do you plan to observe? How big is your budget? Is portability an important factor? How familiar are you with the night sky? Answering these questions will help you narrow down your choices and make you choose a telescope that is right for you.
Choosing The Type
You will normally come across three main different types of telescopes.
- Refractors are the most widely known type of telescope. They have an objective lens in the front of the tube and an eyepiece in the back. They are pretty rugged and require minimum maintenance, however, you will have to spend a little for more aperture size.
- Reflectors use a primary mirror at the rear of the tube to gather light and focus it on a small diagonal mirror. This light is then directed into an eyepiece on the side of the tube. The most common type of reflectors is the Newtonian. Dobsonians are also very popular since they offer the most aperture at a low cost. A reflector telescope does require occasional optical alignment of the mirror using a process called collimation.
- Compound telescopes use a combination of both lens and mirrors. This results in an ultra-portable telescope with advantages of both refractors and reflectors. They are also great for astrophotography.
To know more about them, check out our detailed guide on telescope types for beginners.
Aperture Is Important
The most important factor to consider before buying your first telescope is its aperture. This is the diameter of its lens or mirror depending on the type of telescope you choose. You will find the aperture mentioned on the box or the tube of the telescope. At its smallest, your telescope should have a 70mm or 2.8-inch aperture and more if possible.
A large aperture will allow you to view more faint night sky objects and observe much finer detail compared to a small one. However, this greatly depends on the area you live in. A dark location will allow you to view dozens of deep-sky objects even with a small telescope whereas you would need a telescope with a 6 or 8-inch aperture to see the same objects in a light polluted area.
Considering Focal Length
The distance between the objective lens or primary mirror and the point where an object is brought into focus is known as Focal Length. It is an important factor since it determines how well a telescope can magnify an object. To determine the magnification of the eyepiece, you will divide the focal length of the telescope with the focal length of the eyepiece. The top useful magnification for a telescope is 50 times its aperture in inches or twice the aperture in millimeters.
A Stable Mount
A stable and sturdy mount for your telescope is more important than a lot of people realize. Many telescopes come with tripods or mounts already included in the package. An altitude-azimuth mount allows the telescope to move left-right, up-down like a photo tripod.. A Dobsonian is basically a Newtonian reflector which is placed on a variation of the alt-az mount. An equatorial mount allows movement on a single axis and needs to be aligned with the North Star, Polaris.
A keypad controls the motorized mounts on some telescopes. Other models of these known as GoTo telescopes usually have a small computer that can automatically point the telescope and track night-sky objects. The Orion Starseeker IV 130mm is a great GoTo telescope for beginners.
Final Thoughts On Deciding Your First Telescope
While it can be very tempting to pick up a cheap telescope packaged in a colorful box, most of the times it will be of low quality and probably end up disappointing you. You can always consider a good pair of binoculars if you have a budget of less than $200. Even if you have a lot of money to spend, it is not a wise choice to buy the most expensive telescope out there. It is always better to start with a beginner telescope and learn your way to more powerful telescopes.
It is always a good choice to take your time and consider all of the above-mentioned factors before making a decision about your first telescope. With the right telescope, you will be ready to experience a lifetime of cosmic wonders and exploration.