The Night Sky of October, 2010.

Jupiter is the most prominent object to see in the night sky during October, rising just before sunset it is visible throughout the entire night! Jupiter can be found to the East just after sunset, and due to the rotation of the Earth, it appears dues South at midnight. If you go somewhere really dark, you will be able to see your own shadow cast by Jupiter! I've seen that on a few occasions.

Take a look through binoculars or a small telescope, and see if you can spot the four bright Galilean moons that orbit around Jupiter. Our Moon is conveniently close to Jupiter in the night sky on the 19th & 20th of October, acting as a useful guide. The photo' below shows how close they were together last month.

The Moon begins its appear in the evening sky as a thin crescent on the 8th – a beautiful sight in the evening sky. The Moon reaches full Moon, when it is on the opposite side of the sky to the Sun, on the 23rd.

The summer triangle is still visible in October, despite its name, high in the South at 7pm. The three stars that make up the triangle are Vega, Altair & Deneb. Vega is the brightest of the three stars, and there maybe a planet like Jupiter in orbit around Vega (see the wikipeida entry). Altair is interesting because it rotates in just 7 hours! And Deneb is actually one of the brightest stars we know of – some 250,000 times bright than the Sun! The reason it looks fainter than Vega is only because it is much further away – Deneb is some 100 times further away than Vega. If Deneb was as close as Vega, it would be as bright as the Moon!

Mars & Regulus - a beautiful sight in the evening sky!

Mars and Regulus are just a degree apart in tonight's night sky. Their contrasting colours are a beautiful sight - so do take a look! But be quick, as Mars is orbiting the Sun, it is moving around the sky, and so it will only be close to Regulus for the next few nights. Here are a couple of photographs that I took last night with a zoom lens. In the night sky, the two are separated by the width of a few of your figures at arms length!

The Night Sky for June, 2010

Summer begins this month, and so the Sun is not setting until after 9pm, and darkness does not begin until 10pm. But there is plenty to see this month if you are willing to stay up a bit later.

As soon as it begins to get a bit dark, look towards the sunset, and by 10pm you will be able to see the planet Venus, very low in the sky. It looks a bit like an aircraft coming in to land… but if it is still there 10 minutes later, and hasn’t landed, then you have found Venus!

Look to the left of Venus, and slightly above it, and you will notice a red object – the planet Mars. During the month, Mars is close to the star Regulus, at equal brightness but not as red. On the 6th of June, Mars passes only 1 degree away from Regulus as it moves around the Sun and so moves around the sky.

Then look to the top left of Mars, and you have Saturn, which appears to be quite bright and slightly yellow in colour.

Venus is setting at about 11.30pm, with Mars following it an hour later, and then Saturn is setting an hour after that.

The positions of the planets can be seen in this movie below.

If you now look in the other direction towards the stars rising in the South-East (see graphic below, set at 22:30BST), you will see three bright stars – Deneb, Vega and Altair. Those three stars are known as the summer triangle of stars, and are fascinating in their own right. Vega has a dusty disk around it and maybe a planet; Altair rotates in just 7 hours, making it bulge around its equator; and Deneb is one of the brightest stars we know of. Deneb is over a 100 times further away than both Vega and Altair, but it looks equally bright because it is so big – at least 200 times the diameter of the Sun! If Deneb was as close as Altair, it would be almost as bright as the full Moon!

I will be writing more about what can be seen in this patch of sky over the coming months, as the Earth moves around the Sun to get a better look at this patch of the night sky.