Friday 29 January 2010

Mars reaches opposition

Today, the 29th of January 2010, Mars reached opposition - this means that Mars is on the opposite side of the sky to the Sun (see the diagram of our solar system at the very bottom). So as the Sun sets in the West tonight, Mars is rising in the East. This also allows us to get great views of Mars, and amateur astronomers around the world have been taken some breath-taking images of the planet - such as the one below, taken by Pete Lawrence here in Sussex.

Do make sure you go outside and take a look at Mars! As soon as it is dark, go outside and look East for a bright red object in the sky - that's Mars!

Tuesday 26 January 2010

Sunspots!

There are currently spots on the Sun!

If you want to see the sunspots for yourself, make sure you do it safety! There are plenty of safe ways to look the Sun which will not blind you, such as using a solar telescope, or by projecting an image of the Sun onto paper.

Saturday 23 January 2010

One less comet in our solar system...

These images taken by the NASA/ESA SOHO solar observatory on 20-21 January 2010 show a comet falling towards the Sun (from the bottom left).

As you can see, the comet does not come out the other side, so... bye bye comet! It must have been vaporised by the Sun!

Comets fall towards the Sun frequently (in fact, SOHO has seen over 1600!), but it's always fun to guess if the comet will survive and come out the other side, or just be so close that they are vaporised by the Sun!

The Lasco C3 instrument on board SOHO works by hiding the incredibly bright Sun with a disk (the silhouette of the disk is at the centre, and the arm that holds it in place goes off towards the top right). This allows the camera to see the fainter gas being ejected by the Sun, without the bright Sun damaging the camera.

However, even the planet Venus (bottom left of centre) is too bright for the camera! Venus is so bright, that it fills that part of the digital camera chip with electronic charge, and that charge spills over to the neighbouring pixels forming the long horizontal line. (in fact, my pocket digital camera does axactly the same if I point it at the sun)

Note also that there is a lot of noise on the movie. That is due to cosmic rays hitting the Lasco C3 camera - it's a harsh place is space, and there is no atmosphere to protect SOHO from the cosmic rays.

Oh, and why blue? Well, why not! Each camera on-board SOHO is colour-coded with a different colour, so astronomers immediately know what camera took the image.

Tuesday 12 January 2010

Annular eclipse of the Sun: January 15th 2010

On Friday, there is a Annular Eclipse of the Sun, from 04:05 GMT, with mid eclipse at 07:07 GMT, and ending at 08:59 GMT... yes, that's in the middle of the night for us here in the UK, so unfortunately, we will not be able to see it at all! (and even when the Sun is visible at the end of the eclipse, the Moon is slightly off to one side as seen from the UK)

The eclipse will be visible from Africa and across India, as show in the map below.

Below is an animation I made from a series of photographs taken during the annular eclipse of 2005. The reason it is an annular, and not total, is that the Moon orbits the Earth not in a circle, but in an ellipse. During this eclipse, the Moon is slightly further away than on average, making it appear slightly smaller, and so too small to cover the Sun completely.

More details can be found on the Wikipedia.

If you do happen to be in the path of the eclipse, do not look at it with your eyes, since you will probably be blinded for life. Instead, use solar glasses, a simple and cheap solar telescope, or just use your hands as a pinhole projector!

Monday 11 January 2010

The Night Sky for January 2010

mars0004_7stb We have two evening sky planets that we can see throughout January - Jupiter in the early evening, and Mars (right, as seen through a good telescope) in the late evening. You can see Jupiter setting in the South-West if you look before 7pm, and you can see Mars rising in the North-East if you look after 7pm. So, for a few minutes at around 7pm, you can see two very bright planets at opposite sides of the sky!

On the 17th, the Moon is just to the right of Jupiter, and on the 18th the Moon has moved just above Jupiter. By the 29th of January, the Moon will have travelled to the other side of the sky and will be next to Mars for the night. Saturn is also visible over night, now rising just before midnight in the south and visible until dawn. Unfortunately, we cannot see either Mercury or Venus this month, as they are both too close to the Sun.

The starry highlight of January is still the constellation of Orion, which I discussed in last months's blog.