Humans’ fascination with the stars is as old as our ability to think and ask questions. For millennia we, as a species, were limited to observing the heavens with just our eyes. Of course, back then we were able to see more because light pollution didn’t exist, but making detailed observations was impossible. The invention of the microscope led to the development of the telescope, which allowed people to finally start exploring the larger universe. As technological advances were made and telescopes got bigger and better, their reach and the details they could resolve became broader and more intricate. Astronomy led the way to the acceptance of science, the rise of the Enlightenment, and incalculable advances not only to our understanding of our world and universe, but also the philosophical questions about our place in that world. As said by Carl Sagan in his famous quote “It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known”
Before we move forward which telescope you should buy? How much should you spend on your first telescope? What are the differences between Dobsonians, reflectors and refractors? Let’s take a peek on the history of telescope.
A fun fact, we all have an image of Galileo Galilei as an inventor of telescope. He did made remarkable contributions to telescope which enhanced its magnification but telescope was actually invented by Hans Lippershey in 1608. In 1609, famous Italian mathematician and scientist Galileo Galilei learned of the work being done with lenses and began refining the system, eventually adding a focusing mechanism. He apparently developed the telescope on his own, and is the first known person to point a telescope skyward.
Galileo was able to make out mountains and craters on the moon, as well as a ribbon of diffuse light arching across the sky—the Milky Way galaxy, the sun’s sunspots, and Jupiter’s own set of moons.
He used refractor telescope to view the night sky but nowadays we have three main categories of telescope.
- Refractor Telescope
- Reflector Telescope
- Dobsonian Telescope
Refractor telescope uses lenses to focus light near eyepiece. They tend to be lightweight, easy to set up and intuitive to use, give sharp views and require practically no maintenance. The quality of the optics in the telescope, determined predominantly by their cost, will have a significant bearing on the quality of the views, and the cheap refractors that tend to be popular at electrical goods and camera shops are often disappointing. Generally speaking, smaller refractors less than 90mm diameter are best suited for wider views of the night sky, which might include star clusters like the famous Pleiades, M45
- Interchangeable eyepiecesoffer varying magnifications and increase the range of viewable objects
- Good portability allows for trips to enjoy darker skiesaway from light polluted areas
- excellent for observing objects within our solar system—planets and the Moon and, with the right accessories, they can be used for terrestrial viewing
- Since the optical system is basically a straight line, there are no obstructions from secondary mirrors as there are in Newtonians
- Easy to use and consistent due to the simplicity of design
- needs little or no maintenance and its sealed tube protects optics from image degrading
- Tend to be more expensive per inch of aperture than the other two designs
- Not suited to view distant objects such galaxies and nebulas due to smaller aperture size
- Chromatic aberration due to refraction of light
Generally speaking, smaller refractors less than 90mm diameter are best suited for wider views of the night sky, which might include star clusters like the famous Pleiades, M45
Reflector telescopes use a mirror, instead of a lens, and the eyepiece is located at the side of the main tube. You look through an eyepiece on the side of the tube up near the top. Utilizing a large primary mirror, the Newtonian gives you greater value per inch of aperture, since making a mirror is less labor-intensive than making lenses. Because you can get large apertures out of the mirrors and the lengthened focal length due to the light being reflected from the primary to secondary mirrors and then to the eyepiece, reflectors are ideal for seeing the deep-sky objects that refractors often miss, such as galaxies and nebulae.
- Usually have larger apertures which mean excellent viewing of faint deep sky objects (remote galaxies, nebulae and star clusters)
- Low in optical irregularities and deliver very bright images
- A reflector costs the least per inch of aperture compared to refractors
- No Chromatic aberration as the light is being reflected and not refracted
- Support for the objective mirror is all along the back side so they can be made very BIG!
- Telescope tube of a reflector is shorter than that of a refractor of the same diameter which reduces the cost of the tube
- Generally, not suited for terrestrial applications
- The tube is open to the air, which means dust on the optics even if the tube is kept under wraps
- Reflectors need their mirrors adjusting from time to time
In fact the views offered by a relatively modest reflector can compare favorably with those offered by expensive refractors. I personally own Meade Polaris 114 mm Reflector telescope. If you want to buy one, then click here
Dobsonian telescope use a combination of mirrors and lenses. These telescopes usually have a nice modern design and have 3″ and larger apertures They may be elegantly simple affairs – no wires, no batteries, you just point it at what you want to see – or they may include a full ‘Go-To’ control, which can automatically point the telescope at hundreds of sky objects. they tend to be shorter lengthwise, and this compactness makes them ideal where storage space is limited.
When sky conditions allow, details can be seen within the coloured bands of Jupiter and various colour bands on Saturn, along with the Cassini and other divisions of Saturn’s glorious ring system, not to mention polar caps and features on Mars.
- Most versatile type of telescope with excellent lunar, planetary and deep space observing plus terrestrial viewing and photography
- Best near focus capability of any type telescope
- Closed tube design reduces image degrading air currents
- Compact and durable
- a popular choice as a happy compromise between large enough aperture and manageable size
- Because of the higher magnifications provided by these telescopes, the object being observed will more quickly move out of view, and so they are often purchased with electronic tracking mounts to follow the targets as they move
- More expensive than reflectors of equal aperture
So now as you have a basic idea on types of telescopes, now let’s check out what you need to consider while choosing your first telescope.
- The first and foremost thing you need to look for the aperture size. Aperture refers to the diameter of the telescope’s main optical component (consisting of either a lens or mirror). The size of your telescope’s aperture determines how much light it can capture. The more light that is captured the more objects you can see in the night sky. More light also means greater clarity in the images you see. Because astronomy is carried out in poor light conditions, having a large aperture means the maximum amount of light is captured for a bright and sharp image.
- Magnification is great but not too important. The magnification of your telescope is determined by the eyepiece you use. Changing magnification just involves swapping your existing eyepiece with one that has a higher magnification. Essentially any telescope can have an infinite range of magnification. So don’t get too excited by telescopes that promote a large magnification.
- The next thing you need look for is the type of mount. Mounts can be grouped into two categories: Alt-Azimuth (AZ) and Equatorial (EQ). Each of these allows you to move the telescope to track objects in the sky. Basic earth science teaches us that the Earth rotates, so as you observe an object, it will appear to move across your field of view, causing you have to move the telescope accordingly. All calculations and coordinates for celestial navigation in the Northern hemisphere are taken from their position relative to the Pole Star.
In short, an AZ mount is easy to use than an Equatorial mount. So if you are choosing an equatorial mount there’s a pretty steep learning curve to figuring out how to use an EQ mount properly, so you need to be prepared for a lot of research and reading in the weeks and days leading up to your first observation session with one.
One more important thing before you start using your first telescope is how to use finderscope. Even with a low-power eyepiece, scanning the sky looking for the one star out of thousands—even the brightest ones—will be virtually impossible. For this reason, you’ll want a finderscope. Dot pointers are very popular and easy to use. They are generally unmagnified and are simply a small window, a couple of inches across at most, with a red dot projected into the center. With both eyes open look through the pointer and align the dot on your subject. You will need a lot of practice on working out on this and figuring out how to adjust accordingly.
Astronomy is a niche but emerging hobby that gets more popular as technology makes it easier to get out and get observing. The best way to gauge your interest level, what you’re most eager to see and join the platform are the best for you is to start with the Internet. Join forums and ask questions. You can join my #letstalk session on my Instagram page @unlocking_spacetime and discuss on cosmos and outer space. You’ll be surprised how many are around and right in your neighborhood. Drop your queries if you have any
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