What can you see with a telescope?
Telescopes gather far more light than the human eye, allowing you to see celestial objects that are otherwise invisible to the naked eye. From intricate details on the Moon and the distant planets Uranus and Neptune to glowing gas nebulae thousands of light-years away, a telescope opens up a world of stunning sights.
The Moon and planets – exploring our solar system
Our natural satellite, the Moon, is always worth a look, even without telescopes. However, with the right magnification, you can embark on a fascinating tour of its cratered surface, uncovering details that will leave you in awe. Tip: Avoid observing during a full moon, as the absence of the terminator (the line between day and night) means you’ll miss out on the dramatic shadows.
The seven planets that orbit the Sun alongside Earth also offer spectacular views. With your telescope, you can marvel at Saturn’s famous rings or take a closer look at the gas giant Jupiter. You can even observe sunspots, eclipses, and planetary transits – but remember, when observing the Sun, always use a safe solar filter!
Galaxies, star clusters, nebulae – deep-sky objects
If you're eager to explore beyond our solar system, deep-sky objects are your next destination. Witness the brilliance of globular or open star clusters like the famous Pleiades. Bright planetary nebulae such as the Ring Nebula (M57) in Lyra, or emission nebulae like the Orion Nebula (M42), provide stunning views, even through beginner telescopes. With a larger telescope of at least 150 mm aperture, galaxies like our neighbour Andromeda appear much clearer. Moreover, a journey through the Milky Way with the right astronomical telescope will be an experience you won’t forget.
TIP
Not sure where to start? Our monthly Sky Guide highlights the best celestial sights for you to enjoy.
How are telescopes constructed?
Telescopes are composed of three main parts: the optical tube, the mount, and the tripod.
Optical tube
The optics are the heart of the telescope. They collect light and create a magnified image of the celestial body you’re observing. Different designs are used, each with its pros and cons:
Refracting telescopes (refractors)
When most people think of telescopes, they probably picture refractors. These use lenses to focus light at a point, creating an image that’s then magnified by an eyepiece.
There are two main types: achromatic and apochromatic refractors. Due to the different wavelengths of light, refractors can sometimes produce coloured fringes around bright objects. However, these chromatic aberrations are significantly reduced in the more expensive apochromats. Refractor telescopes are known for their sharp, high-contrast images and don’t require regular alignment.
Reflecting telescopes (reflectors)
Reflectors use mirrors to gather light. The light collected from celestial bodies is reflected off a primary mirror at the end of the telescope tube. It then strikes a smaller secondary mirror, which redirects the light to the eyepiece, where the image is magnified. The classic Newtonian reflector remains popular among hobby astronomers.
Reflectors are prized for their colour accuracy since, unlike refractors, they don’t suffer from chromatic aberration. They are also more cost-effective to produce. The viewing position is comfortable, even when observing objects near the zenith.
Catadioptric telescopes
Catadioptric telescopes combine lenses and mirrors. Popular models include Maksutov-Cassegrain and Schmidt-Cassegrain systems. Their compact design and long focal length make them highly portable and easy to transport. They also require less frequent alignment. With a small focal ratio of f/10 or less, catadioptric telescopes are particularly suited for observing planets.
A Note for Nature Lovers:
If you opt for a classic Newtonian reflector telescope, you’ll have a specialist for astronomical observations. However, the image will be inverted and reversed, which isn’t an issue for stargazing but makes this design less suitable for daytime nature and landscape observations. For those purposes, a refractor telescope is a better choice.