Jupiter and Saturn
It will be very tempting to swing your new telescope straight towards the Moon as soon as it’s set up. After all, it will be the brightest and most obvious thing in the sky, and you’ll have looked forward to seeing it through your own telescope for years. But the Moon will have to wait a little longer, as it’s too close to being full. Instead, look to the west where you’ll see two stars shining close together, low in the sky.
Those ‘stars’ are actually the two largest planets in our Solar System, Jupiter and Saturn, and they will be so close in the sky on Christmas night – just a Moon-width apart – that they will both be visible in your telescope at the same time. You’ll have to start looking for them around 16.30 UT, not long after sunset, and you won’t have long before they set.
Through your telescope you’ll see both planets as tiny yellow-white discs, Jupiter’s crossed by several darker cloud bands and Saturn’s surrounded by those famous rings. Don’t expect to see the rings as clearly as the Voyager or Cassini probes saw them; they will look very small through your telescope, but no less beautiful for that. If you zoom in on each planet individually with a high magnification eyepiece
25 December, 16:30 UT
– one with a smaller number in mm (millimetres) on it, which indicates its focal length – you’ll see two of Jupiter’s huge family of moons shining close to it, one on either side of its disc, looking like tiny stars. Titan, Saturn’s largest moon, will also be visible close to it.
As you look at this pair of planets it’ll be fascinating to think that although they look close together in the sky they are actually almost five times further apart than the distance between the Sun and the Earth, and that Jupiter is so huge it could contain a thousand Earths with room to spare.