Nene Valley Astronomical Society
The Local Society For Amateur Astronomers In Wellingborough & East Northants
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Starhopping Around The Spring Sky

A Guide To Finding This Seasons Brightest Stars

 

It is often said that the stars at this time of the year appear less brilliant than those of the winter season and whilst it is true that by a mid-Spring evening we have lost the magnificent constellation of Orion and his retinue, there is still much to observe.  Despite the rapidly shortening amount of darkness at this time of the year, we are (hopefully!) rewarded with slightly warmer temperatures making for slightly more comfortable observing conditions.  This guide is intended for those who have no prior knowledge of how to identify this seasons stars and is therefore very much aimed for the beginner.

 

By a mid-Spring evening, the circumpolar constellation of Ursa Major (whose seven brightest stars make up the asterism of The Plough) is more or less directly overhead, making this time of year ideal to do some exploring of our old friend.  Moving inwards from the outer most star in the handle of the Plough, the second star in is the star Mizar.  Mizar is probably the best well known (and most observed!) double star in the sky.  Keen eyed observers may be able to split Mizar and it component star Alcor without optical aid, but even for those of us who can’t it is easily visible through binoculars.  Truthfully, Mizar and Alcor are not related, Mizar is 60 light years away from us and Alcor 80 light years away, making this a ‘line of sight’ double, but still a nice view nonetheless.

 

Following the curve of the handle of The Plough downwards towards the South-East and you will come to a bright star about half way up the sky by 10pm on an April evening.  This is Arcturus which is the brightest star in the constellation of Bootes.  Arcturus itself appears noticeably orange to the unaided eye and is a red giant star, of which our Sun will become one in a few billion years time.  Arcturus is the fourth brightest star in the night sky, more down to it’s close distance to us (around 36 light years) rather than being a stellar powerhouse.  Its deep orangey hue will become more apparent if binoculars or a small telescope are used to view it.  The rest of the constellation of Bootes contains stars much fainter than Arcturus, but are still visible to the unaided eye from town suburbs and resemble a kind of kite shape, with Arcturus being at the base of the kite.  Bootes does contain a number of colourful double stars to view, including Izar (epsilon Bootes) a third magnitude star to the north-east of Arcturus whose component orange and blue stars make a nice colourful contrast through the eyepiece of a 6” telescope.

 

Our next target is Spica, the brightest star in the zodiacal constellation of Virgo.  To locate Spica, draw a line from Arcturus directly towards the South.  The first bright star you come to in the south-east (slightly fainter than Arcturus itself) is Spica.  Spica lies about 260 light years away from us and is the 15th brightest star in the night sky.  Slightly to the north-west of Spica, and to the unaided eye in a rather barren batch of stars, is a cluster of galaxies – the Virgo Galaxy Cluster which contains over 3,000 member galaxies several dozen of which can be observed through amateur astronomers telescopes.

 

 How To Find Arcturus and Spica by using The Plough to Starhop.

 

Returning back to The Plough, I’m sure most readers of this article will be familiar with using the two ‘pointer’ stars to find the pole star, Polaris.  We can also use these two stars to find our next target, Regulus in Leo.  Just follow the line of these two stars towards the South and roughly half way between the southern horizon and the zenith can be found a collection of stars which look like a back to fron question mark.  At the base of this question mark shines a bright star, roughly the same brightness as Spica, this is Regulus.  Regulus lies around 85 light years away from us.  Lieing approximately half way between Regulus and Spica at present can be found a bright distinctly cream coloured ‘star’, which is actually the planet Saturn.

 

Our final two stars to spot are Castor and Pollux in Gemini.  Although the constellation of Gemini is more traditionally classed as a winter constellation, it is still nicely placed for view well into the mid-Spring evening sky.  To find Castor and Pollux, use the two stars in the bowl of the Plough as illustrated in the chart below, follow this line across the sky towards the West.   The two bright stars lieing close together are Castor and Pollux.  Pollux is the slightly brighter of the two and is an orange giant star very similar to Arcturus in Bootes.

 

How To Find Castor and Pollux by using The Plough to Starhop

 

 

Happy Spring Starhopping!