Continuing on from last month let’s look at how some more of the more obvious constellations and stars can be used as pointers and sign posts in the night sky. Let’s go back to the Plough which is part of the constellation Ursa Major, the Great Bear. The 2 pointer stars point towards Polaris, the pole star. This is not a bright star. It’s significance is it’s location rather than it’s brightness. It is the star that is above the North Pole so is always a pointer to the north Passing straight past Polaris will take you to Cassiopeia, a W or M shaped constellation. See the chart below and pass through Polaris to Cassiopeia. The stars of Cassiopeia are not too bright but it is quite easy to identify the shape of the constellation.
Now look south, the constellation of Orion dominates the night sky in the winter. Next month we’ll explain the movement of the sky and why different constellations appear in Spring, Summer, Autumn and Winter. But as this is December’s issue we must mention the great Hunter, Orion.
Looking towards the south, look for the pattern of stars below. You’ll probably find the 3 stars of the belt first.
Depending on light pollution you may only find the brighter stars. The 3 stars almost in a row are Orions’ belt. Below that are his sword and within the sword is the Orion Nebulae M42. Click the link for more information http://en.wikipedia.org/wiki/Orion_Nebula
As a guide Orions’ belt is about 3 degrees from each end star, Altinak and Mintaka .
From Orion it is a simple hop to Taurus using the 3 belt stars as pointers or in the opposite direction to find Sirius, the brightest star in the sky.
We’re starting a new feature for those members new to astronomy. This month to start you off we have “Getting started in astronomy”, a guide to those “first steps” in astronomy and a view of some key constellations of the northern skies. Plus “Constellation of the month”, a closer view at Andromeda this month.
Stars appear to be scattered across the sky and how can you ever make any sense of them. And
which ones are planets, how do you find them. In the northern skies there are about 2,000 stars viewable up there with your naked eyes. But most of us may be able to see 200 maximum due to town light pollution blotting out the fainter stars.
The first things to think about are where shall I observe and what do I need to take outside with me.
Find somewhere safe and away from street lights directly shining on you. If you can find a safe site away from street light that is even better. Back gardens are a good starting place. Do go outside and don’t just look through windows. Give you eyes 15-20 minutes and you’ll begin seeing a lot more. You’ll need to keep warm and comfortable so anything from warm clothes to a comfy outside chair or even deckchair could be used.
You don’t need heavy expensive equipment just a planisphere, ( check Phillips Planisphere at Amazon.co.uk) decent astronomy book (Collins Gem Night Sky) and a pair of binoculars (10×50 are ideal). You’ll also find that decent stores such as Waterstones will stock Planispheres and Collins Night sky book.
I’m going to assume you know how to locate the Plough (above). This is a great starting point for your night of star gazing. The plough is a part of the constellation of Ursa Major but is easy to find and is a great signpost looking north. We measure the distance between stars as we see them from Earth in degrees, minutes and seconds. More of that later.
Now let’s use the various signposts of the Plough to help you move to other constellations. Look for the 2 pointer starts that will take you to the North Star, Polaris and onwards to Cassiopeia. Going in the opposite direction takes you to the constellation of Leo and the backwards question mark, “The Sickle”. Back to the Plough and follow the handle of the Plough and “arc” to the star Arcturus in
the constellation of Bootes. Continuing past takes you to Spica which is the brightest star in Virgo.
Use your planisphere to look around the main stars and find Andromeda, near Cassiopeia, maybe even find M31 with your binoculars. Don’t forget to look at your Night Sky book too.
By using your hand you can gauge the distance in degrees between objects. Your fist held out at arms length measures about 10 degrees. Also at arms length the width of your index finger is 1 degree and the middle 3 fingers together is about 5 degrees.