What size telescope do you need to see the rings of Saturn?

You can see the rings of Saturn in any telescope – even a small telescope for beginners. But the views you get will vastly differ depending on what telescope you have. 

If you want to get the very best views of the sixth planet from the Sun and its incredible ring pattern it pays to know the difference between 'slow' telescopes that are best for planetary astronomy and 'fast' telescopes that are better for observing deep sky objects. Here's everything you need to know about choosing the best telescope to see the rings of Saturn: 

What size telescope do you need to see the rings of Saturn?

If you just want a glimpse of Saturn's rings (and its largest moon Titan) then almost any telescope will give you that – even a 50mm/2-inch refractor and a 25mm eyepiece – though don't expect it to be anything other than tiny in the field of view. For a noticeably better view use a 102mm/4-inch telescope, with real detail in the rings becoming evident when you reach 125mm/5-inch.

According to Celestron, the best telescope designs for seeing Saturn are Maksutov-Cassegrain and Schmidt-Cassegrain telescopes, largely because they gather the most light, have longer focal lengths and can accommodate eyepieces offering 150x magnification or more.

How to get the best views of the rings of Saturn

How far a telescope can see depends on a range of factors. Since Saturn is about 845 million miles from Earth at its closest, the best telescope for seeing the rings of Saturn with extra resolution is naturally going to be the one that can gather the most light. That means choosing a telescope with as much aperture as possible. However, it also means choosing a telescope with a long focal length that can take eyepieces with a higher magnification (higher power). 

• Aperture: the size of the lens or mirror, usually expressed in millimetres and inches (the higher the number, the better)
• Focal length: the distance from the objective lens to the focal point (the longer, the better for planets)
• Focal ratio: this is the focal length divided by the aperture in mm (the higher the number, the ‘slower', which is the best for planets)
• Magnifying power: focal length divided by eyepiece (for example, 1325mm focal length and 10mm eyepiece = a magnification of 132.5x)

The bottom line is this: the longer and heavier your telescope the better it will be for seeing the rings of Saturn.

When is the best time to see the rings of Saturn?

Since Saturn is an outer planet that takes a whopping 29 Earth-years to orbit, each year Earth gets in between it and the Sun. Not only is this when Earth is closest to Saturn – and when Saturn looks as large as it ever does – but it's also when Saturn's disk is fully illuminated by the Sun. Dates coming up at time of writing are 14 August 2022, 27 August 2023 and 7 September 2024. In practice you will get great views of Saturn's rings for about a couple of months either side of these dates. Not the right time? Here are some other things to point your telescope at in the meantime. 

Read more:

• How to choose your first telescope
• How to set up a telescope
• Telescopes vs binoculars for stargazing