The bright planets
Distant worlds make captivating viewing
Your first sighting of a bright planet – Mars, Jupiter, Saturn, even Venus when it’s in a dark, night-time sky – in a telescope eyepiece can be a very special thing. But, as with observing the Moon, prepare for a dynamic visual experience that will require patience and careful observation to make the most of the moments of good seeing. Though all four of the above mentioned worlds are captivating through a telescope of around, say, 150mm in aperture, their angular diameters – that is the size they appear to be through the telescope’s optics – will be fairly small.
And, again, just like when observing the Moon, using a very high-power eyepiece won’t necessarily give you a better view of the details on the planets – a medium level magnification is usually a better bet in most cases, rather than the shortest focal length eyepiece you have in your kit box.
Trained on Jupiter, a telescope with a 150mm aperture will show the main equatorial bands and indications of some of the subtler atmospheric details, as well as the Great Red Spot. ▲ Jupiter, as imaged through a 14-inch Cassegrain telescope, reveals the fine detail of the gas giant’s cloud systems...
A similar setup will show the rings of Saturn and potentially hints of the soft banding on the planet – good seeing will also reveal the larger structures in the rings, namely the Cassini Division, the dark band located between the A and B rings.
Meanwhile, Mars at opposition will be a small ochre disc, but careful observation will show the more prominent, dark, so-called ‘albedo’ features, such as the famous Syrtis Major – which appears as a vaguely triangular dark-brown patch near the middle of the Red Planet’s disc – and, possibly, one of the polar caps.