How to Choose Your First Telescope?
5 Mistakes We May Make
Abstract
If you're new to telescopes, we strongly recommend you read the guide below before you buy any scope!
This guide concentrates on visual observing, as opposed to astrophotography. If you’re new to astronomy, it’s smart to gain a thorough grounding in visual astronomy before you go to astrophotography.
There's no one "perfect" telescope — just as there's no such thing as a perfect car. The telescope you want has two essentials: high-quality optics and a steady, smoothly working mount. But don't overlook portability and convenience —the best scope for you is the one you'll actually use.
NO.1- Aperture: A Telescope's Most Crucial Specification
For new player, the most popular apertures in the market are: 70mm, 80mm. If your budget allows, go with 80 mm. From my personal experience, 70mm is for child use only, it's too tiny for adults.
Does that mean you should rush out and buy the biggest telescope that you can afford? Not necessarily.
A telescope that lets you see the faintest of objects isn’t any good if you don’t want to use it. Telescopes with big lenses or mirrors tend to be heavy and bulky. That will be harder to use for new astronomers. In this case, you’re much better off with a smaller telescope that’s easily portable.
Besides, the cost of building a good lens rises very steeply as the aperture increases. So, check your budget. Bigger and more expensive telescopes will allow you to see fainter objects but remember that the smaller the telescope, the easier it will be to transport, use and store when it's not in use. Smaller telescopes are usually cheaper too,so you don't have to break the bank to get a good view of the cosmos!
For new player, the most popular apertures in the market are: 70mm, 80mm. If your budget allows, go with 80 mm. From my personal experience, 70mm is for child use only, it's too tiny for adults.
NO.2- Magnification: Just Walk Away!
When seeing a telescope for the first time,a novice often asks,"How much does it magnify?" The answer is, "Any amount you want."
Department store telescopes will often advertise magnifying power - something like "200x" or "400x". If you see a telescope advertising this, walk away. Magnifying power is a marketing gimmick for low-quality instruments.
Magnification (power):The amount that a telescope enlarges its subject. It’s equal to the telescope’s focal length divided by the eyepiece’s focal length. Any telescope can provide an almost infinite range of magnifications, depending on the eyepiece that you use with it.
So if you have different eyepieces, you can change the magnification of your telescope. But don't get the idea that super-high powers will do you much good.
Two main factors limit how much power you can use productively with a given instrument: aperture(again) andatmospheric conditions. The aperture determines how much detail you will be able to see even if you have a large magnification. Having a small telescope with a large magnification will only zoom in on a blurry image because your telescope can't collect enough light to allow you to see any more detail. Atmospheric conditions can also limit the detail you see. Even with the clearest skies, our atmosphere causes detail to be lost, so magnification only goes so far.
As a good rule of thumb, a telescope's maximum useful magnification is twice its aperture in millimeters. And that's if the scope has perfect optics and the night air happens to be unusually steady. In other words, a high-quality 80-mm scope should not be pushed much beyond 160× (that's under ideal atmospheric conditions). So if you see a 80-mm department-store telescope labeled as delivering "more than 160 power!!!", just walk away. Again, Avoid telescopes that are advertised by their magnification .
NO.3- Focal Length: A Common Misunderstanding
I saw many 80mm and 70mm telescopes with 400mm, 500mm, 600mm or even 900mm focal length. Will that be the longer the better? NO, that's another trick in marketing. It's another use of magnification, it seems, the longer the higher magnification.
Let me explain what will happen if you increase a 80mm aperture, with 400mm focal length refractory telescope to 600mm focal length:
600mm tube is 1.5 times longer than normal 400mm tube, that will make it even harder for travel and camping.
Again, the longer the focal length, the harder to find the star, reference the finder scope part.
For new astronomers, going with 300~400mm focal length will be best. You will find it easy to use. Again, The scope that gets used regularly is always a better scope than the one that rarely or never gets used.
NO.4- The Mount: A Telescope's Most Under-appreciated Asset
Another aspect of a telescope you need to consider is its mount. This is what keeps the telescope steady and allows you to smoothly turn it to view different parts of the sky.
Weak mount (single screwed, photo below) will be too frustrating to use and not give you much viewing satisfaction. Trust me, a sturdy mount will save your life.
Why is a sturdy mount so important? As you can imagine, during our observation, our eyes keep touching the eyepiece . If your mount is weak(single screwed), the telescope will keep vibrating without stopping. I've thrown away a lot of such garbage. It's a total waste of money.
That's why we've invented a new double hinged mount (photo below) to give our user a sturdy experience.
NO.5- Finders: Which is Better for New Astronomer? Red Dot Finder VS Finder Scope
Aiming a telescope is tricky: Telescope sees only a tiny portion of the sky, it might not be in focus for what you are looking at, and slight bumps can throw off your aim. That is why most telescopes come equipped with some kind of aiming device to help you find objects in the night sky.
In the past this was almost exclusively with a Finder Scope – a little, low powered telescope on top of the main telescope’s optical tube with a cross-hair that was used to aim.
But it's harder to use for new astronomers.
Even if you have seen the star with your naked eye, but it's difficult to find it in your finder scope due to the narrow view filed it provided. Trickier to align properly with the optical tube, especially for new astronomers. Cheap ones extremely hard to aim.
Red dot finders involve no magnifying optics. Instead the red dot finder has a window that you look through and a red dot is projected to show where the telescope is aimed.
They are simple to use, because you can see the entire sky when using them, they offer a very wide field of view.
This makes it easy to use, especially for new astronomers. It's as simple as aiming a flash light at the moon.
The scope that gets used regularly is always a better scope than the one that rarely or never gets used.