Saturn is arguably the most popular planet, certainly with children and the public at large. Its wonderful system of rings, well seen through even a small telescope, makes it unique in the Solar System.
Unlike Mars and Jupiter, both of which are currently rising high in the Taurus/Gemini area, Saturn lies rather low in the sky from UK shores, among the stars of the largely Southern constellation of Aquarius. Despite this, Saturn still achieves a reasonable altitude of between 26° and 31° from UK shores when it culminates at about 1am in early September. Town and city dwellers just need to find a reasonably flat horizon from the south-west around to the south-east to view Saturn clear local buildings and vegetation.
Saturn shines at magnitude +0.6, significantly brighter than any stars in its immediate vicinity and the four stars that lie at the corners of the Great Square of Pegasus, seen immediately north of Saturn and about twice as high in the sky. So there’s no issues with local light pollution spoiling the view; Saturn’s easy to see with the naked eye can be observed through any telescope.
Saturn comes to opposition on 8 September, when it lies 1.295 million kilometres (8.658 AU) from us. It’s found in north-eastern Aquarius, about 4° south of the boundary with Pisces to the north. Saturn rises at 7.30pm GMT from London and can be observed from around 10pm BST until 4am, during which time the planet lies above 20° altitude. Saturn can be observed under similar circumstances for the rest of September, and remains in the evening sky until early February, 2025.
Observers grabbing a telescopic view of Saturn for the first time may be disappointed. The angle at which we see the rings is ever changing and for a period of a few successive years the rings are tilted towards us at a narrow angle, unfortunate for the diminished view we get. This month the rings are tilted by just 3.7°, a far cry from the 27° or so when they’re fully open, which last occurred in 2017.
Saturn’s major rings have a diameter of 270,000 kilometres but are less than 100 metres thick! They are not one solid mass but split into three distinct, major rings seen through a telescope. Outer Ring A is separated from broader Ring B by the famous 3,000km-wide Cassini Division. Inside Ring B is the dark Ring C, or Crêpe Ring, a tough spot even under good observing circumstance, owing to its dimness and the distracting glare from Saturn’s disc.
Saturn has a huge family of moons – 146 with confirmed orbits at the last count. Eight are visible in amateur telescopes. The giant moon Titan (mag. +8.3) is by far Saturn’s dominant satellite and is only two per cent smaller than Jupiter’s giant moon, Ganymede, its 5,150km (3,200-mile) diameter making it larger than the planet Mercury and 50 per cent larger than our Moon. A small telescope easily shows it and you can plot its position on any night along its 15.9-day orbit.
Rhea, Saturn’s second moon, shining at mag. +9.7, and Tethys and Dione, at +10.2 and +10.4, respectively, are all within range of a small- to medium-aperture telescope. Iapetus, Saturn’s third-largest and most outlying major moon, is a bit of an oddball. Owing to its remarkably contrasting hemispheres, one bright and the other dark, it shines brighter by 2 magnitudes when it’s at greatest western elongation from Saturn compared to when it is at eastern elongation (mag. +10.5 vs +12.7). It’s next at its brightest on 13 October.
