A telescope can make a great gift to your loved ones. If used carefully, it could last them a lifetime. It can open a portal to the universe and provide a lifetime of enjoyment. However, just as there is no perfect car, there is no ‘perfect telescope’. Instead, you should choose based on your interests. So here’s a complete guide into the uncharted world of Telescopes.
Types of Telescopes
There exist mainly three types of telescopes for hobbyists. They are the Refractors, Reflectors and Compound.
Refractors
These are what most of us stereotype as a telescope– a long skinny tube with a lens at one end and an eyepiece at the other (just like the one Gallelio used). They are lovely telescopes and are superior performers in inferior conditions. However, they are expensive and not recommended for beginners. They also encounter something called chromatic aberration meaning that you will see coloured rings around stars.
Reflectors
These telescopes are great for beginners and they use mirrors to collect and reflect the light. They are great for beginners in the sense that they have larger mirrors which enables them to have better light collecting capacity. These telescopes do not have chromatic aberration and are relatively low cost. However, these telescopes have open mirrors which will expose them to dust and humidity. Despite the cons, I would recommend these to any beginner for their ease of use and because they are practically unbreakable.
Compound
These telescopes use a combination of mirrors and lenses to collect the light and tend to be more expensive and are not recommended for beginners.
Here is a quick tips that you should consider when buying his/her first telescope. Firstly, you have to choose a telescope depending on your tastes. If you are planning to pursue the hobby seriously, I would suggest that you get a good quality and expensive telescope with which you can observe other galaxies. But, if you’re thinking of just looking at NEOs (Near Earth Objects) or the moon with it, I would suggest that you go for the low-end ones.
Aperture
Whenever people are looking to buy their first telescope, I have often heard them say, “Give me the one with the highest magnification”. But in contrast, they should be looking for the one with a larger tube-diameter (aperture). Generally, a telescope’s aperture is measured in inches or millimetres. As a practice, try to choose a telescope that has an aperture greater than 2.8 inches(70mm). A larger aperture can collect more light. This is a boon for people living in cities as it lets them see more detail in faint objects. For example, an 80mm aperture would suffice to observe the Milky way from dark places. Yet, you would require an aperture of 6-8 inches to see the same things from a sub-urban area. Regardless of your skies, a larger aperture lets you see more clearly than a smaller scope.
Focal Length
A telescope’s magnification power partly depends on the Focal length of the telescope. The larger the focal length – the larger the magnification and the smaller the field of view. I do not recommend large focal lengthed telescopes to beginners as it makes it harder to locate the target they’re looking for with a small field of view. A telescope’s focal length is written on its frame and for an eyepiece, it’s labelled on its side. To calculate the magnification of a telescope, you have to divide the focal length of the Telescope by the focal length of the eyepiece.
Some Caution
Be wary of telescopes that are advised by their magnification rather than their aperture. Typically, a telescope’s maximum useful magnification is 50 times its aperture in inches (or twice its aperture in millimetres). So you’d need a 6-inch-wide scope to get a decent image at 300×
Mounts
A telescope’s mount is one of the most important pieces of gear in your arsenal. Without a stable mount, it doesn’t matter how good your telescope is since all the images will appear wobbly.
Manual Mounts
These mounts require you to manually adjust levers and turn spindles to move the telescope. They would help a beginner but remember to get a good and stable one. They require no prerequisites and can be practically set up anywhere.
Equatorial mounts
These mounts are bulky, weird-looking, require to be pointed towards the North star and take a long time to set up. However, they allow smooth moving to track the night sky. It is difficult to operate and not at all recommended for a first timer especially if he/she has kids.
Computerised mounts (Go To mounts)
These mounts have a remote which can be used to control and move the telescope. They have their GPS module and do not require any alignment. These mounts got their name from a button on the remote which says ‘GO TO’. Selecting a target and pressing this button would point the telescope towards the desired target. As all good things do, they come with a couple of drawbacks. Firstly, they are expensive and a few models are bulky. Secondly, these mounts require a power source which might be a problem if you are in the middle of a desert (You can hook it up to your car battery though) They make a perfect choice for people living in cities because manually pointing the telescope at an object in the sky is difficult in intense light pollution.
Optics
Eyepieces
All telescopes come with eyepieces. However, for telescopes, it is the eyepieces that magnify an object. Just when you think you’ve used your telescope to its fullest potential, think again. Upgrade the eyepiece and you’ll be blown by the change. An eyepiece increases the focal ratio of your scope thereby affecting the magnification. Generally, eyepieces are bought in sets– The Meade’s Super Plössl is a perfect collection for a beginner. The good thing about them is that they are interchangeable between telescopes. So buying an exceptionally good eyepiece enables you to use it with multiple telescopes. Eyepieces are counter-intuitive. The lower the number on their label, the higher they magnify. Having an excellent eyepiece is more important than having an excellent telescope.
Barlow Lens
The Barlow lens comes in between the eyepiece and the telescope. It increases the focal length. Essentially doubling the magnification of any lens. Barlow lens comes in 2x, 3x, 5x etc.
You get what you pay for
A standard way to tell which telescope is of good quality is by the price. Good telescopes cost around $200-$400. If you have bought a telescope at some random thrift shop for around $50-$100, return it immediately! It can’t be of good quality and a telescope with which you are frustrated won’t do you much good.
Choose wisely
I have seen a lot of people who end up buying very expensive telescopes and honestly don’t know anything much about them. If you are buying something which you and your family will use, choose wisely. A good quality telescope if maintained well can last you a lifetime. Once you have bought your first telescope, your tastes improve and after a few years, you can upgrade to bigger and better ones.