amateur astronomy

Nature Guide: Stars and Planets – out now!

I’m very pleased to announce that a new astronomy handbook that I helped to write, Nature Guide: Stars and Planets, has just been published by Dorling Kindersley.

The book is a 352-page, lavishly illustrated, introduction to astronomy complete with equipment advice, star charts and in-depth guides to all of the constellations. You can see some sample pages from the book on DK’s website.

If you’d like to pick up a copy, the book is available from all good high-street bookshops as well as online via The Book Depository, Amazon etc.

Watching a wandering star

Over the past few weeks it’s been hard to miss Venus shining away high in the west after sunset. At the end of March it was less than 3 degrees from the crescent Moon, while the first week of April saw Venus drifting past the Pleiades star cluster. Below I’ve collected together some pictures of the planet that I’ve taken recently; clicking on each one will take you to a larger version.

The wide-field pictures were all taken with a Canon 550D DSLR and a zoom lens, while the close-up (showing Venus’s phase) was captured with a Philips SPC900NC webcam and an 8-inch Schmidt-Cassegrain telescope.

A celestial spectacle from the space station

A crop of the NASA image. Click the image for the full resolution NASA version. Credit: NASA

I’m busy working on a new astronomy book at the moment, so don’t have much time to blog, but I really couldn’t let this amazing new image slip by without posting it here.

It was taken by astronauts on the International Space Station and has to be one of the best images from orbit I’ve ever seen. Aside from the impressive space hardware on show (that’s STS-135, Space Shuttle Atlantis, docked on the left hand side) the image shows numerous other celestial sights.

Beyond the solar panels and Space Shuttle we can see the green glow of the aurora dancing over the limb of the Earth, while in the background there are lots of objects familiar to amateur astronomers in the southern hemisphere. A quick glance shows the Coalsack Nebula, the rich star fields of the Milky Way, the Southern Cross, a hint of the Carina Nebula, and even the globular cluster Omega Centauri. Simply stunning!

Observing the 2010 Geminid meteor shower

Over the coming week the 2010 Geminid meteor shower gets underway, building up to a peak which is expected on the morning of 14 December. I thought now would be an ideal time to repost a few excerpts from the blog post I wrote about the shower last year.

The position of the Geminid meteor shower radiant (see text below), in relation to the surrounding constellations. Click the image for a larger version. Credit: StarDate magazine. Used with permission from The University of Texas McDonald Observatory

The best time to look for the meteors will be on the night of the 13/14 December. How many you’ll see depends on several factors, such as your local light pollution levels and the cloud cover. Steve Owens has a great post about this here, where he explains how to calculate the number of Geminids you can expect to spot from your viewing location. Meanwhile, here’s what I had to say about the Geminids this time last year:

“Meteors are produced when tiny pieces of space dust enter our atmosphere at enormous speeds. As they do the air ahead of them is compressed violently causing it to heat up. This tremendous heat in turn makes the meteor glow as it streaks across the sky. It’s amazing to think that the average meteor is created by a piece of celestial detritus no bigger than a grain of sand.

Ordinarily on a clear dark night you might see a handful of meteors every hour. These are known as ‘sporadic’ meteors as they don’t belong to a particular shower. However when a meteor shower is underway there’s a good chance you’ll see many more, as the shower is supplementing the handful of sporadic ‘shooting stars’.

A meteor from the 2009 Geminid meteor shower darts through the constellation of Hydra, close to the star Alphard, as captured by Pete Lawrence. Credit: Pete Lawrence

Meteor showers occur when the Earth passes through a trail of debris left by a comet as it passes through the Solar System. The particular object that creates the Geminid meteors measures around 5km in diameter and is known as 3200 Phaethon. It was found in the early 1980s and is in fact designated as an asteroid, though it certainly has some cometary traits. Perhaps, some have argued, it is a ‘dormant’ comet.

If you go out over the next few nights and see any meteors you’ll know you’ve spotted a Geminid if it appears to come from a point in the constellation of Gemini. This point is known as the ‘radiant’. The constellation that the radiant is located in gives the meteor shower its name; so the Geminids come from Gemini, the Orionids come from Orion etc.

In terms of where to look, my advice would simply be to look up. Gemini is high in the sky over the next few nights at around 1:30am, and with the Moon out of the way later on in the evening, we’ve got some good observing conditions for this year’s shower. Wrap up warm and sit back in a sun-lounger if you can, as this should stop your neck from getting tired and give you a better, more comfortable, view of the sky.

Meteor showers like the Geminids are a great chance to get together with friends to observe too, as the more eyes the better. You can join in with the special Geminid ‘Meteorwatch’ event on Twitter by tagging any Geminid meteor observations you tweet with the hashtag #meteorwatch.”

Clear skies and good luck meteor watching!

A video guide to buying your first telescope

If you’re thinking about buying your first telescope – or are perhaps thinking of getting one for a friend or relative – you might be interested in the latest episode of the Sky at Night Magazine vodcast. It addresses a few of the basic questions you may have about telescopes, their various designs and how to use them.

I’ve embedded the video below, but if you have any more questions (after all, there’s only so much we could fit in one vodcast) leave a comment below, and I’ll do my best to get back to you.

For best quality playback select the 720p HD button.

Video credit: Sky at Night Magazine Top telescope image credit: