Before you buy a telescope understand that size matters! A larger size mirror or lense on a telescope produces a higher quality image and is the single most important part of a telescope.
But if you’re new to astronomy and want to start viewing the stars through a scope, what objects in outer space can you hope to see? What size telescopes let you see them? And how much is it going to cost you?
That’s what we’ll answer here today.
Astronomics has some good detail but I will expand on it here to include costs. Note I cover the three types of optical telescopes here (refractors, reflectors and catadioptrics).
Comparison of size, $$ price range and what you can see
- Size: 60mm to 70mm refractor, at powers of 25x to 125x (solar system objects generally need 60x and up)
- Price range: $90 – $200
- Solar System visibility: Lunar craters 4-5 miles wide, Saturns rings, some cloud detail on Jupiter, faintly Uranis and Neptune
- Stars visibility: Double stars separated by as little as 2 arc seconds; faint stars down to magnitude 11.5
- Deep Sky Object visibility: Bright nebulae, Large star clusters and most of the Messier objects (on a dark night) but with little detail
- Size: 80mm to 90mm refractor, or 4″ to 4.5″ reflector, or 3.5″ to 5″ catadioptric, at powers of 16x to 250x
- Price range: $180 – $300
- Solar System visibility: Sunspot details (with an appropriate solar filter), the phases of Mercury; lunar detail less than three miles in diameter, Mars’ polar caps and major dark surface features; additional cloud belts on Jupiter, the shadows of Jupiter’s moons, Saturns moons, more detail on Uranis and Neptune
- Stars visibility: Double stars separated by 1.5 arc seconds or less, faint stars to better than magnitude 12
- Deep Sky Object visibility: many globular clusters, colorful nebulae, planetary nebulas, and galaxies; many of the brighter NGC objects (with little detail) and all of the Messier objects
- Size: 4″ to 5″ refractor, or 6″ reflector, at powers of 30x to 300x
- Price range: $400 and up
- Solar System visibility: Faint comets and brighter asteroids, lunar features less than two miles wide; more detail in Jupiter’s cloud belts, subtle cloud belts on Saturn’s disk
- Stars visibility: Double stars separated by about 1 arc second, faint stars down to magnitude 13 or better
- Deep Sky Object visibility: Better detail on NGC objects, Hundreds of star clusters, nebulae, and galaxies (spiral features)
- Size: 6″ to 7″ refractor, or 8″ reflector, or 7″ to 9.25″ catadioptric, at powers of 50x to 400x
- Price range: $800 and up
- Solar System visibility: Dimmer asteroids are now visible as faint star-like points, lunar features under one mile across, large clouds and dust storms on Mars, as many as six or seven of Saturn’s moons, More detail on Jupiter’s Moons
- Stars visibility: double stars separated by less than 1 arc second in very good seeing; faint stars down to magnitude 14
- Deep Sky Object visibility: Globular clusters visible almost to the core, much internal detail in nebulae and some visible structure in many galaxies from a dark night
- Size: 10″ or larger reflector or catadioptric, at powers of 60x to 500x
- Price range: $2000 and up
- Solar System visibility: Lunar features to much less than one mile across; small clouds and significant surface detail on Mars, moons of Mars, a lot of detail in Jupiter’s clouds and belts, Neptune’s moon Triton visible; Pluto visible as faint star-like point
- Stars visibility: Double stars separated by as little as 0.5 arc seconds in excellent (and accordingly very rare) seeing conditions; faint stars down to magnitude 14.5 and below
- Deep Sky Object visibility: Many hundreds if not thousands of globular clusters, nebulae, and galaxies, virtually all NGC and IC catalog objects, faint color visible in some of the brighter nebulas from a dark sky site
Keep in mind that most deep sky objects won’t product much color if any (save for the very large scopes) because the human eye can’t absorb enough light from those objects. You’d need to use a camera to capture color for things like Galaxies and Nebulae.