Jupiter and its moons – an ideal target for beginners
Got a new telescope and not sure what to do with it ? Congratulations! An ideal starter for you is to look at one of my favourite sights in the night sky – Jupiter and its moons. Even with a simple telescope, you should easily be able to see the four main moons. By doing this, you are following in the footsteps of Galileo as it was his observations of these four moons which helped him realise that not everything orbited around the Earth and moved us on from a system with the Earth at its centre to one with the Sun correctly at the centre.
When to look for Jupiter
When Jupiter is in the right part of its orbit to appear in our night sky, it is unmistakeable, not as bright as Venus but still very obvious. I usually like to check, before I go out with my telescope, to find out where I expect to see the 4 moons.
I’m not sure why but I do find it amazingly reassuring to then observe that the moons are in the correct place. It would be a bit of a disaster if they weren’t! (Just remember that the optics of your telescope might give you an upside-down view or a mirror-image view compared with the website graphic).
The real Wow factor
For a real wow factor, make use of the long winter nights and look at Jupiter early on, say 6pm and note where the moons are. Go inside, have a nice evening and then look again at perhaps 11pm. The moons will have moved! Io the closest moon to Jupiter has an orbit time of just 1.7 days so in 5 hours, it completes nearly 1/8th of its orbit while Europa with an orbit time of 3.5 days will also show an appreciable movement in a relatively short time. The first time I did this, a line from the poem Desiderata popped into my mind : “And whether or not it is clear to you, no doubt the heavens are unfolding as they should”. A peaceful thought with which to end a day.
And finally : Don’t be too concerned if one of the moons is missing. This just means it is on the part of its orbit which is directly behind or in front of the planet. Also, it is best to bring your telescope indoors between viewings on a long evening otherwise condensation could form on the optics which a) won’t do it much good and b) will spoil your view anyway.