While the naked eye and binoculars can reveal much of the night sky, a telescope reveals even more. When you see Saturn’s rings or the moon’s craters with your own eyes, you may have a “wow” moment.
However, choosing the right telescope can be difficult. There are telescopes with lenses and telescopes with mirrors. Hand-operated telescopes and electronically controlled telescopes. Telescopes also come in a variety of sizes, making trade-offs between light-gathering power, portability, and price.
There’s a lot to consider, but changes in price and technology have made spectacular views of space more accessible than they were just a decade ago.
Read more: Want to start stargazing? A professional astronomer explains where to start
How large should the aperture be?
Aperture is fundamental to a telescope. The larger the condensing lens or mirror, the dimmer the objects you can see. The diameter is doubled from 50mm to 100mm, and the light collection area is quadrupled.
The aperture also limits the level of detail you can see due to light diffraction (interference).
Again, bigger is better. Telescopes with larger apertures produce sharper images than telescopes with smaller apertures of comparable design. Earth’s turbulent atmosphere can also blur the image, limiting the detail visible at apertures above 150mm.
Cheaper telescopes are sometimes advertised by their magnification, but small telescopes with extreme magnification will only make the image blurry and reveal less detail.
Refractor or reflector?
Should you buy a telescope with a refractor or a reflector? It depends on what you want to see and your budget.
refractor telescope
refractor telescope Suitable for observing objects on the earth or in the sky. Short focal length refracting telescopes (where the light focuses close to the lens) are very compact and suitable for viewing at low magnifications, making them ideal for viewing large areas of dark rural skies.
However, there are pitfalls. While 70 mm aperture refracting telescopes are very affordable, larger refracting telescopes are often more expensive than comparable reflecting telescopes.
Refracting telescopes also suffer from chromatic aberration, where different colors are not brought into a common focus. This is especially noticeable when stars develop halos of color at high magnification. This can be alleviated using complex lens designs, but this increases cost.
reflecting telescope
reflecting telescope Use mirrors to focus the light. These tend to be large and don’t suffer from chromatic aberration.
dobsonian telescope Featuring a simple Newtonian optical design and wooden mount, it is a very cost-effective (if sometimes bulky) option for larger apertures. Schmidt Cassegrain Maksutov telescopes, which use a combination of lenses and mirrors, are more compact (a big advantage), but also more complex and expensive.
How do I find what’s in the sky? Depends on the mount
Want to see celestial bodies? The telescope must be pointed in the right direction, stabilized, and track objects moving through the sky (due to the Earth’s rotation).
To do this, use a telescope requires mount, are often sold together with a telescope, but can also be purchased separately. Mounts fall into two broad categories.
equatorial mount The axis of is aligned with the Earth’s axis, so a single motor can compensate for Earth’s rotation. These mounts were essential for taking long exposure images with telescopes before the advent of computers, and they tended to be relatively heavy.
ortho azimuth mount They have vertical and horizontal axes (such as how a camera is mounted on a tripod) and tend to be cheaper and lighter than equatorial mounts. With the advent of cheap computing, they can now be used to automatically point and track celestial objects.
To point the telescope at a celestial object, you can move it manually or use electronic equipment, such as a motorized “goto” mount that moves the telescope automatically.
Fully manual telescopes are cheaper than automated ones, but they require you to navigate the sky yourself.
Electronic aids for traveling in the air are rapidly evolving and becoming cheaper. Many telescopes on the market today use GPS and smartphone apps, which simplifies the process and makes everything more portable.
Do I need a finder scope?
Regardless of the telescope orientation, having an auxiliary “finder” scope with a 30-50 mm aperture is useful for smaller telescopes, but essential for larger telescopes.
Large telescopes typically only see a small portion of the sky, making it difficult to find your way forward. A finder scope with a wide field of view and crosshairs simplifies your work. Even telescopes with goto electronics often need to be calibrated using bright stars, and a finder scope makes it easier to locate them.
What about the eyepiece?
The important parts of most telescopes are eyepiece lens you see through it. Sometimes decent telescopes are sold with very cheap eyepieces, but upgrading to something better is relatively inexpensive.
To begin with, use a low-power eyepiece to view a wide area of the landscape, and a high-power eyepiece to view the planets.
pull sle eyepiece It’s reasonably priced and has a nice view. More complex eyepieces that provide better vision are also available and are much cheaper than before.
If you want to see the sun, Must Get something specially designed solar filter. Never point a telescope (including a finder scope) at the Sun without a filter. This can cause permanent damage to the eye and cause the lens to shatter.
What should I do if I want to take astrophotography?
Taking basic astrophotography has become even easier with your smartphone. You can also hold your phone up to the telescope’s eyepiece to take pictures of the moon or planets, but you’ll get better results with an adapter that holds your phone firmly in place.
Of course, you can get better images with a dedicated astronomy camera that can take very short exposures (for planets) or very long exposures (for fainter nebulae and galaxies). For long exposures, automatic tracking of celestial objects is essential, which increases the price of the telescope.
smart telescope It is a relatively recent addition to the market. These goto telescopes do not have eyepieces and only capture images electronically. Modern detectors are more sensitive than our eyes, so even in the presence of light pollution, relatively small handheld telescopes can capture some very spectacular images.
However, the experience of seeing the universe directly with your own eyes through the eyepiece is lost.
Try before you buy!
If you have a local amateur astronomical society, you can sign up or attend a star party. There should be a lot of telescopes, and the owners will be happy to wax lyrical about them.
You can also experience the size and mechanism of a telescope firsthand at a specialty store (during the day only). For example, a telescope may be too large or too technical for your needs.
Shopping online can save you money, but customer support may be less than at a local store. You can get a good deal on a used item, or the seller may let you test the telescope on the moon or planet before you buy.
There are many things you need to prepare before purchasing a telescope. Caliber, size, cost, and other factors must be considered. But there are a lot of good choices out there, and if you make good choices, you can see great things. And maybe there will be a “wow” moment.