Calling all astrology buffs! Alison Begley (Astronomer Royale to PSHQ) has come up with a monthly guide to the stars behind your sign. This month it’s Sagittarius aka the Archer. If you are Sagittarian then the following words sum you up (apparently) optimistic, restless, enthusiastic, adventurous, honest, irresponsible, outspoken, independent. Sound like you?

Sagittarius (November 22 - December 21)

For all you Sagittarians thinking about a new hobby, now is the time to jump in with both feet, bring some friends… and don't forget your jumper - it can get chilly out there…

How to find Sagittarius… you'll need to follow the instructions to find the bright star Antares in Scorpio and look to the left. Or at 10pm near the end of August Sagittarius is due south. Look for the teapot; the rest of the constellation lies below the horizon in the UK.

This fantastic part of the night sky not only shows off some beautiful star-forming clouds of gas and the brightest part of the Milky Way, but when you look at Sagittarius you are also looking into the very centre of our galaxy and its all-consuming supermassive black hole.

The Milky Way, our galaxy, is a spiral shaped, thinnish disk of stars, dust and gas orbiting around a central bulge. What we see as a cloudy white band across the sky is a vast number of distant stars as we peer through the disk edge on. Towards Sagittarius the Milky Way becomes increasingly luminous and the galactic centre becomes obscured.

Despite not being able to see it directly, stars whizzing around the galactic centre tell tales of a massive object contained in a tiny volume - a black hole a million times the mass of the Sun. And although the black hole is very slowly and quietly eating the galaxy from inside out, our Sun is well out of the way of its hungry grasp. So, Sagittarians, there is still time to plan for that special holiday you've always wanted…

But Sagittarius isn't just about what you can't see. The Lagoon nebula is visible with the naked eye, but don't be fooled, it isn't blue! This nebula is a place where stars are born. Once they ignite they burn a bright blue, but the surrounding gas and dust absorbs this blue light and re-radiates it as red, giving the Lagoon nebula its red glow.

If after this you are still finding your chair a bit too comfortable to go outside, find an Aries - apparently they are great motivators!

Following on from Professor Roy Lowry’s rocket record attempt (still waiting to hear from those Guinness people) a couple of weeks ago, here’s some rocket science to brighten up the dullest rainy afternoon.

Caution: this rocket can fly up to 3-4m. Adult supervision required.

You will need:

• Film canister with lid (clear film canisters where the lid presses inside work the best)
• Baking powder
• Vinegar
• Teaspoon
• Toilet paper

What to do:

1. Take the lid off the film canister.
2. Measure three teaspoons of vinegar into the canister.  
3. Take a sheet of toilet paper and place it on top of the canister.
4. Press it down to form a small well. Don’t press it down so far that it touches the vinegar! The aim is to keep the two ingredients apart.
5. Place a teaspoonful of baking powder in the well.
6. Press the lid on tightly and trim the excess toilet paper from the edges.
7. Do not turn it over yet and definitely DO NOT SHAKE IT! You don’t want it to go off and hit you in the eye.
8. Find a clear, safe area outdoors. It is not a good idea to do it where a slumbering dog or nervous cat is in the vicinity. Come to think of it make sure grandma or granddad are not snoozing in the garden either.
9. Turn the canister over and place it lid-down on the ground then retreat to a safe distance i.e. at least 2m away.
10. Brace yourself. It will take about 20 seconds or so to launch. The advantage of the clear canister is that you can see the mixture bubbling up. This means that you don’t have to get impatient and approach it just as it shoots up.
11.  Whe-hay! Thar she blows! If you’re lucky it will go over the shed much to the pleasure of any watching kids.

What’s going on?

Vinegar and baking powder react together to form carbon dioxide gas. The gas builds up until it forces the lid off the film canister. The gas pushes downwards which in turn (thanks to Newton and his Third Law) causes the canister to be forced upwards. However, if it just doesn’t look rockety enough for you checkout the fantastic website for BBC Norfolk. Norfolk astronomer and Chairman of the Norwich Astronomical Society Mark Thompson gives instructions on building a rocket using a similar device and there’s a template to make the rocket body, nosecone and fins! Houston we have lift off. It’s also featured in a mini-movie as part of our ‘SciCast’ pilot project, 7th down.