30 Dec 2010

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Satellite Rocket EXPLODES!

It is a disaster when a space shuttle/rocket crashes or dose not even make it into space. Millions of pounds are wasted. And many people have died in such crashes. The most recent was on Saturday, it was a Indian space rocket, the Geostationary Satellite launch vehicle(GSLV), carrying the GSAT-5P communications satellite. It exploded in the first stages of its flight. Luckily nobody was inside the rocket at the time. It is unknown what caused the explosion but investigations are underway.

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Ever wanted to be part of a scientific team? Ever wanted to do something amazing, like discover a planet orbiting a distant sun? Ever wanted to take part in a real science project and maybe make a difference?

Like any real scientist, you will need a lot of patience, as you looking at much data that is unexciting (but is still interesting in its variety), but it is sooooo worth it for the finds you make (see some examples - the ones I have come across and marked -;"> of my transiting planets and eclipsing binaries at the end)!

One way you can do this is to sign up to Zooniverse and take part in one of the space projects that interest you (please read their 'about' page here):

Planet Hunters: Study data from NASA's Kepler mission for thousands and thousands of stars, try to spot where planets cross a star (a transit) and cause the star to dim for a short while.

The Milky Way Project: Aims to sort and measure our galaxy, the Milky Way by finding and drawing bubbles in beautiful infrared data from the Spitzer Space Telescope.
Moon Zoo: Explore the Moon in unprecedented detail using images from NASA's Lunar Reconnaissance Orbiter.
Galaxy Zoo: Hubble: The latest version of the original Zooniverse project, where you can help astronomers figure out how galaxies form and evolve by classifying their shape.

Solar Stormwatch: Help spot explosions on the Sun and track them across space to Earth. Your work will give astronauts an early warning if dangerous solar radiation is headed their way. And you could make a new scientific discovery.

Galaxy Zoo: Mergers: Understanding what happens when galaxies merge is one of the most important questions in astronomy. Help astronomers by trying to match a merger from SDSS with a simulation.

Galaxy Zoo Supernovae: Help to catch an exploding star. Astronomers are following up on your best candidates at telescopes around the world.

Old Weather: Help scientists recover worldwide weather observations made by Royal Navy ships around the time of World War I.

Here are a few examples of interesting stars I've personally come across and marked in my favourite project, Planet Hunters

First a couple of the single transits I've marked (with only one 'dimming' in the data given) - if you click on them you can see the raw data I found them in:

Then there's data with more than one reading:

or an eclipsing binary (with two stars of different brightness orbiting each other):

This one isn't so clear, but if you click on it and enlarge it using the magnifier at the bottom of the image on that page (two circles, one at each side, you can drag in to expand a particular area. Then you can move the highlighted area across to see other features):

But, if you join up, you will see that you have to look at many different possibilites before you come across any of these (if you're lucky you might see one in your first hundred or so, but you may have to wait longer). More likely you will see images like these, where you will have to use your own judgement whether or not there's anything there:

You will come across many different star types - ones that vary over several hours or days, or ones that seem to only increase or decrease over the readings, ones that give off white noise, or ones that have such intricate patterns you will be amazed!

Here's just a very small selection:

I can't even begin to show all the types you will come across, but, for me, it has been an exciting adventure into astronomy, and research....I hope you find it so too...

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18 Dec 2010

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Brian Cox gives 'crash course on skies marvels'

Stargazing LIVE:
3, 4 and 5 January 2011, 8pm, BBC2

Three nights of exraordinary astronomical events
on 3- 5 January 2011 on BBC2, with Brian showing
Dara the astronomical basics. Liz Bonnin
will tell us how stars affect us (live from Hawaii)
- watch it if you can!

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12 Dec 2010

(Please click images to enlarge)

Constellation of the Month: Cassiopeia

(vote in the sidebar which will be the next Constellation of the Month!)

Last month we looked at the constellation of the Plough. I hope everyone managed to get a glimpse through the snow clouds and find it. Maybe you even had the chance to name the stars (and show off a little to your friends you know something about it! :-) )

This month, I was going to do Ursa Major's smaller bear friend, Ursa Minor (which means 'Small Bear'). However, it was pointed out to me that a constellation that is very clear in the sky just now is Cassiopeia, and this would be better to learn next, because it will help guide you through the sky easier...you'll soon see why!

What does it look like?

Let's start off by finding out what this asterism (remember, asterism means pattern of stars?) looks like. Easy! It's shaped like a huge W

(although, because it swings around the North star as the Earth turns (i.e. it is circumpolar), sometimes it will look like it's fallen on its side, and sometimes it will look like an M

Trying to understand where the W shape comes from, I have looked at a lot of images on the Internet. I haven't found most of them very helpful (I can see the stars, but can't make them into the W shape). These are a few of the images of Cassiopeia I found [click on image to see better]:

After some searching, I found an old one I liked, that I could understand where in Casseopia's body the (five) main stars are, which I've marked with yellow dots. The W is on it's side (looking more like a 3):

This one is also clear (and appears to be as described by the ancient greeks):

The Main Stars

So, now it's time to name the main stars (there are more, but we'll leave that for a bit): Caph, Shedar (also called α Cas, α Cassiopeiae, Shedar, Shadar, Schedir, or Shedir), Tsi (Gamma Cassiopeia), Ruchbah (Delta Cas) and Segin (Epsilon Cas):

And see what it looks like with a few other stars surrounding it. (Try squinting...that sometimes helps):

Can't see the stars? (Truth be told, neither can I in photos, though I can see them clearly outside :-) ) Take a look at the left image below. It's exactly the same as the one above, but with the stars of the constellation highlighted with yellow dots; and in the right image the constellation lines are back, so you can compare with the image above (Really, it's easier to see them in the sky!)

Ok, so now we know what Cassiopeia looks like, we need to know where to find it. If we can find the Plough, we can find Cassiopeia:

Where is it?
Cassiopeia and the Plough are on opposite sides of the North star (Polaris) to each other, both rotating around it.

This means that, if the Plough is low on the horizon below the North Star, then Cassiopeia will be high in the sky above the North Star and more easily visible, and vice versa. When The Plough is high, Cassiopeia is low on the horizon. As they rotate around there will be times when both will be about level with each other and the North Star, and all three will be clear.

So, when you can't see the Plough, Cassiopeia can be used to locate the North Star (Polaris):

This is the reason I decided to do Cassiopeia before Ursa Minor - because, if you can find both the Plough and Cassiopeia, it will make finding Ursa Minor much easier, since it's tucked nicely between the two!

It's all Greek to me!

Before I go into what objects and interesting things can be found in Cassiopeia, I'm just going to flash this table at you.
Lots of star names are made from combining a greek letter and the constellation name. The nearer to the beginning of the alphabet the letter, the more likely it is that it's a brighter star eg Alpha = brightest, Beta = next brightest and so on....
So, a very quick look at the alphabet, will give you a clue to how 'important'/ prominent is a star within the constellation.
(I'll put this up in the sidebar for future reference.)

Interesting Objects in Cassiopeia

An object map (from Derekscope) shows where some of the following objects are located [as usual, click to see clearer]:

Heart and Soul Nebulae

Cassiopeia seems to be a very active constellation... To start with, there's the wonderfully named Heart and Soul Nebulas (guess which one's the heart!):

...which can be found here:

Here's an image of the Soul Nebula, containing the the radio source, W5 , a massive star-forming region within the nebula (6500 light years away) (infrared):

This is the famous 'Mountains of Creation', within the soul nebula, where stars are born:

...and this one shows how a super massive sun in W5 is blowing off the dust discs from smaller suns, both images taken by the Spitzer Space Telescope:

It's windy in Cassiopeia! Image credit:
NASA/JPL-Caltech/Harvard-Smithsonian CfA

Rho Cassiopeia
And talking of active, there are only seven known yellow hypergiants in the Milky Way, and two of them are in Cassiopeia. The first is called Rho Cassiopeia. It is about 11,650 light-years away from Earth and yet, amazingly, it can be seen with the naked eye. It's about 550,000 times the brightness (luminosity) of our sun! You can find it just here near the end of the W:

This particular star gets brighter and dimmer (it's a variable star) as it throws off its outer layer about every 50 years, and may be close to going supernova (In fact, some scientists think it may have already gone supernova, and may now be a black hole or a neutron star, but that we're just too far away to have seen it yet!)

The other yellow hypergiant in Cassiopeia is called V509 Cassiopeia (V509 Cas), which is also a variable star, though smaller than Rho Cas.

Cassiopeia A (Cas A)

Whilst Rho Cas might have gone supernova, there are two stars in Cassiopeia that have definately exploded. The first was in 1572, which became brighter than Venus in the sky, and the second is called (unimaginatively) Cassiopeia A (or Cas A). This is the most recent (about 1667) supernova in our own Milky Way, and is the 'brightest' radio source in the sky:

The blown off gas and dust (the remnant) can be faintly seen:

(It's thought that the neutron star in the middle
might actually have a carbon atmosphere)

Although there are many, many images in a google search for Cas A, I had great difficulty finding out where it was actually located!In the end, I estimated its position using Stellarium:


Apart from being a hotbed of supernova and star forming activity, Cassiopeia has another claim to fame - it's absolutely, super massive, amazingly big Alpha star, Shedir! If you look at this image, you can see how small it makes our sun (which is actually a pretty average sized sun) look:

[Our sun's in the top right corner]

Though it's so big, and although it is the Alpha star in Cassiopeia, it's not the brightest star of the constellation. That claim to fame goes to Rho Cas (above).


There is a binary star (two stars linked by gravity to each other) in Cassiopeia, which can be found quite close to the second 'V' dip of the W, called Achird:

As for the Plough, I'll leave you with an idea of the distances of the stars in the constellation. I managed to find two source for this. The first is from Warren-Wilson:

and the second takes a 3D look at the stars:

(We're looking up from the bottom right corner)

There is so much more information I've collected for this constellation, for instance:

but, if I were to put everything there was about this constellation here, I would be writing this for a long time to come. So, I hope there is enough here to get you going and explore this constellation yourself!

'Constellation of the Month' now moved to new website:

9 Dec 2010

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Look up, or you'll miss it!

Two astronomical events coming up:

Meteor showers (two) :
The Geminids - Best early in the evenings of 13th and 14th December (providing it isn't cloudy...again!). This is a chance to watch a lot of 'shooting stars', or meteors (they are not called meteorites until they touch the Earth's surface).

You can use the Plough (Big Dipper) to help you find Gemini:

...and the Geminid meteor shower centre (called the radiant - they don't all come at once, but if you take pictures of all the ones that come, and overlay them they would appear to be coming from one area of sky:

Most meteorite showers are caused by the Earth passing through pockets of dust left behind by comets as it travels round the sun, but the Geminids are unusual in that they are thought to be debris left from an asteroid called 3200 Phaethon (pronounced fay -e-thon).

Apparently the meteors are multi-coloured (I have yet to see this!) and are supposedly white, yellow, blue, red and even green... let me know in the comments if you see the colours?

(The Ursids 17th - 25th, with a maximum on 22nd December. Unfortunately, the brightness of the moon will make them hard to see)

Lunar eclipse:
21st December (See Wikipedia for more details and some good pics!)- you'll have to be up early to catch it though...the first gentle shadowing begins at 5.29am GMT (Greenwich Mean Time /London time), as the Earth begins to block out some of the sun's rays.

But that's not the dramatic bit we think of a lunar eclipse. The Earth's shadow covers the whole of the Moon at about 7.40am:

Though it will look dark, take a closer look. Will you see the reddish tinge? This is caused by the longer light waves, from the sun, being refracted by the Earth's atmosphere:

Unfortunately, the moon will be sinking below the horizon quite quickly, so the haze of the atmosphere might make it more difficult to see the red-brown colours. It may be that binoculars would be a good idea, if you have any. And since the moon will set half way through the eclipse about 8.15am (in Wadhurst area), we won't see it become light again. (If you miss this one, then the next one will be next June (2011), though this one promises to be just as low in the sky)

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