Some of the prime targets for small telescopes that I wrote about in my previous article in January 2008 are no longer well positioned for viewing. So here are some more that you can seek out in autumn (fall) 2008. Don’t forget that you can still check out the Moon too!
The largest planet in the solar system is low in the evening sky for observers in the northern hemisphere but one of the brightest objects in the heavens. Even a small telescope will show Jupiter as a disk, but one that is decidedly squashed, due to its rapid spin – it rotates in a day that lasts less than 10 hours. (Conversely, Jupiter is high up for southern hemisphere observers).
Turbulence in our atmosphere will make it difficult to see much detail in Jupiter’s cloud cover, but be patient and you may make out some of the planet’s bands and belts. If viewing conditions are good, more powerful instruments should show the famous Great Red Spot when it is turned towards us. (The image here is deliberately “non-Hubble” and closer to what you will really see in a small scope).
It can also be fascinating to watch the movements of Jupiter’s four biggest moons, Io, Europa, Callisto and Ganymede, as they circle the planet like a mini solar system. Known as the Galilean satellites after they were spotted by Galileo in 1610, they resemble a string of beads and may be seen in steadily-held binoculars.
M31 – The Great Andromeda Galaxy: We live in a collection of billions of stars that is known as the Milky Way due to its appearance, viewed from within, as a shimmering band across a dark sky. Our galaxy is just one of billions of other “star cities” and the largest that is close to us is M31 in the constellation of Andromeda – the M stands for Messier, the French comet hunter who added it to his famous catalogue.
This galaxy – a spiral like our own – is bright enough to be visible with the unaided eye alone in a moonless sky. Binoculars show it well, or turn the smallest of telescopes on it and it will resemble a bright, elongated blur. Don’t expect to see individual stars or any of the detail in professional photos, but marvel at the fact that the light you are viewing left the galaxy 2.5 million years ago, before Man appeared on Earth. See, too, if you can pick out its two satellite galaxies M32 and M110.
M13 – a bright globular cluster: On the opposite side of the heavens to the famous Orion stands another celestial strongman, Hercules. Spot him high above the western horizon when it gets dark in early autumn. Four moderately bright stars mark out the mythological hero’s torso, and the next gem on our list may be found a third of the way down between the two stars on the right side.
M13 is a ball of more than 300,000 stars tightly packed together. Just visible to the unaided eye in ideal conditions, it resembles a fuzzy glow in binoculars but its true nature is revealed in telescopes which begin to resolve, or pick out, the individual stars as pinpricks of light.
Globular clusters form like halos around galaxies and more than 150 are know to surround our own Milky Way’s core. M13 is the best know in the northern sky but southern astronomers enjoy a more spectacular treat in the shape of Omega Centauri, which was bright enough to be mislabelled like a star in Centaurus.
Albireo: Still flying high in the sky in the evening at this time of the year is Cygnus, the swan, despite the fact that its brightest star, Deneb, forms part of what has become known as the Summer Triangle. Cygnus’s cross-shape is meant to resemble a swan in flight with outstretched wings. At the opposite end to bright Deneb in the longer bar of this cross is Beta (β) Cygni, or Albireo. To the unaided eye it appears simply as a moderately bright star, but turn your new telescope on it and discover a real gem. You will find that Albireo is actually a double star and the brighter 3rd magnitude yellow star is accompanied by a 5th magnitude blue companion. The contrast of colours makes Albireo one of the mosy beautiful double stars in the heavens.
Double cluster: Yet another hero of the heavens is the Greek character of legend Perseus. This constellation is rich in delights for binocular and telescope users because it lies closse to the star-rich Milky Way. But its most famous inhabitants, close to the border with Cassiopeia, are the two collections of stars known as the Double Cluster.
Binoculars will show them as rich concentrations of stars but through a telescope they sparkle like gems in a jewel box. They are termed open clusters because they don’t have the structured, spherical form of the globular clusters, and individually they are labelled NGC 884 and NGC 869.