What Can You See with a Telescope?

What can you see with a telescope? This must be one of the most frequently asked questions of all among would-be skywatchers, which is understandable given that even a half-decent lower-end telescope still presents quite an investment. Before I go any further, however, I must dispel one myth that many first-time telescope buyers fall for: magnification is NOT the most important specification to look out for.

Aperture, which refers to the diameter of the main optical component of a telescope, is by far the most important characteristic. As a general rule, the absolute highest useful magnification is around 50 times the aperture size in inches or twice the aperture size in millimetres. In other words, don’t be seduced by the claims of 500 to 1,000 times magnification of those cheap department store telescopes.

#1. Small Telescopes and Binoculars (Price range: $70 to $200)

Even with a small telescope or decent pair of binoculars, the Moon reveals an unprecedented level of detail.

I generally don’t recommend buying any telescope that costs less than about $100. In most cases, you would be better off getting a decent pair of binoculars than buying a budget telescope, particularly one from a second-rate brand. However, binoculars and monoculars can also make a great accompaniment to a good telescope, since you can use them to more easily find specific targets in the sky.

At this price range, you should be able to get a reasonable refractor telescope with an aperture of 50 to 70 mm or a reflector with an aperture of 70 to 114 mm. If you’re specifically looking for something that’s portable enough to travel with, a refractor will usually be the better choice, since they’re usually lighter, and they’re also suitable for viewing terrestrial targets.

With a telescope in this price range, you can expect to see craters and other features of the moon as little as 5 miles (3 km) in diameter. You’ll also be able to see the phases of Venus, the red disc of Mars, the largest cloud bands of Jupiter and the rings of Saturn. If conditions are extremely good, and it’s is near its closest point to Earth, you may even see the polar icecaps of Mars as tiny white patches.

Provided you’re comfortably far away from any major sources of light pollution, a small telescope should reveal countless stars that you can’t see with a naked eye, including the pair that make up the Albireo binary system. You’ll also be able to see various nebulae and galaxies as small white clouds. Andromeda, our closest galactic neighbour, will resolve itself as a white cloud with a distinctly bright core.

#2. Mid-Range Beginner Telescopes (Price range: $250 to $500)

The disc of our nearest galactic neighbour, Andromeda, is easily visible with a mid-range telescope.

Unless portability is a major concern or your budget is very tight, I would generally recommend buying a telescope somewhere within this price range, since you’re likely to get a lot more for the money. At the lower end of this price range, you should be able to find a decent 114 mm reflector telescope or a reasonably high-quality 90 mm refractor. At the higher end, a 130 mm reflector should be within reach.

We’re starting to get into the territory of some serious optical power here, so you’re certainly not likely to be disappointed, particularly if you’re a first-time telescope user. You’ll be able to see features on the lunar surface as little as two miles (3.2 km) long, and the polar ice caps of Mars and the cloud bands of Jupiter and Saturn should reveal themselves clearly in good viewing conditions.

In very clear, dark skies, a 114-130 mm reflector telescope or equivalent will reveal numerous deep-sky objects. The Dumbbell and Orion nebulae should be clearly visible, albeit not with distinguished colours. You’ll also be able to see the distinct shapes of some of the closer galaxies in our galactic neighbourhood, such as the Pinwheel galaxy, and numerous other Messier objects.

*My own telescope is a Celestron NexStar 130 SLT. I highly recommend it for those seeking a mid- to high-end beginner telescope that’s easy to set up and use. When I get the chance, I’ll post a proper review.

#3. High-End Telescopes for Advanced Users ($600 to $1000)

The rings of Saturn are clearly visible with any mid- to high-end telescope in good viewing conditions.

Those willing to spend some serious money will be able to choose from a range of reflector telescopes with aperture sizes of 150 mm or more or refractors with apertures of 100 mm or higher. Although quality optics in this range certainly don’t come cheap, you’ll still find plenty of beginner-friendly products, complete with built-in computers and star finders to help you home in on specific targets.

In this price range, the solar system will reveal itself in an unprecedented level of detail. You’ll be able to see many of the major surface features on Mars, the Great Red Spot on Jupiter and the main cloud bands of Saturn. Observing the Moon, you’ll be able to distinguish surface features as little 1.2 miles (2 km) in diameter. With a 150 mm reflector, even Uranus will should reveal itself as a tiny cyan-coloured disc.

Deep-sky objects start to display a lot more features with apertures of 150 mm and greater. Some of the closer and larger galaxies, such as NGC 4036 and NGC 5198, reveal their distinct shapes and very bright nuclei. Objects such as the Dumbbell and Orion nebulae will start revealing their true colours, particularly when combined with some long-exposure astrophotography.

#4. The Largest Consumer Telescopes for Enthusiasts ($1,200 upwards)

With an aperture of at 250 mm or greater, the Orion Nebula starts to reveal its stunning hues of blue and purple.

Once you start heading into the territory of 200 mm aperture sizes and greater, the universe will reveal itself in an unprecedented level of detail. Unfortunately, you should also expect to spend upwards of £1,000 for the luxury, with the largest consumer telescopes costing in excess of $10,000. However, for this sort of money, you can get an enormous 609 mm Dobsonion reflector.

At the lower end of this category of enthusiast scopes, you’ll be able to easily distinguish between the major rings of Saturn and observe the seasonal variations and larger dust storms on the surface of Mars. The Moon will appear breathtakingly close too, revealing objects as little as half a mile (0.8km) in diameter. Neptune will even appear as a tiny disc, with its largest moon Triton appearing as a point of light.

With apertures of over 250 mm, some deep-sky objects start to reveal their true colours not just to long-exposure photography, but even to the naked eye. The Orion, Dumbbell and Bubble nebulae make for particularly splendid targets for these large telescopes. You’ll also be able to see the details of many faraway galaxies, such as the spiral arms of the Whirlpool Galaxy, and planetary nebulae like M57.

Final Words

The above should only be taken as guidelines, particularly with regards to aperture sizes and price ranges. After all, there are many factors that come into play regarding your skywatching experiences, by far the most influential of them being light pollution. You’ll see a lot more the further away you get from urban regions, with remote, mountainous regions offering by far the best viewing opportunities.

It’s also important to understand the difference between astrophotography and what you’re likely to see with your own eyes. Astrophotography makes extensive use of long exposure times to capture the true colours of nebulae and other deep-sky objects. This is something that the human eye simply can’t do. As such, nebulae and galaxies typically appear monochrome to the eye, except in very large telescopes.

Please don’t let anything I’ve said in this guide put you off. My intention is purely to set realistic expectations. When you combine those with a quality product from a reputable brand, you’ll be in for a truly unforgettable skywatching experience. When you see the rings of Saturn, the ice caps of Mars and galaxies millions of light years away for the first time, you certainly won’t be disappointed!