Date: November 29, 2011
Title: Four Small Constellations in the Northern Hemisphere
Podcaster: L Cate Kendal
Link: http://ww.legofusker.net/astronomy.htm
Description: In this podcast, we take a short look at four faint constellations in the Northern Hemisphere, and some of the interesting objects that can be seen in them with binoculars.
Bio: L Cate Kendal is a science writer, theoretical physicist and amateur astronomer living in Scotland. She has written for the magazine Astronomy Now and does science outreach volunteer work with the Royal Observatory in Edinburgh.
Sponsor: This episode of “365 Days of Astronomy” has been sponsored by NO ONE.
Transcript:
Hello. My name is L Cate Kendal, and welcome to this podcast. It will explore some of the interesting objects visible in binoculars in the less obvious constellations that can be found in the Northern sky in late autumn and winter.
There are some constellations that demand attention. When you go and look out at the stars at night, your eye is invariably drawn to the large constellations, those big, bright groups of stars that dominate the sky. In the northern winter, these are The Plough of Ursa Major, Orion the Hunter striding across the sky, and the tail end of the summer triangle in the west.
Certainly the big constellations have their charm. They are great for enticing people to look up at the sky and see what is on show with just the naked eye. It’s not only bright stars that can be seen, but there are different types of objects, such as the Orion Nebula, or the Andromeda Galaxy.
The next step up from naked eye observing is using binoculars or a small telescope. And there are plenty of guides to suggest good targets. For this podcast I’ve chosen to focus on four smaller constellations. Not because they are necessarily that special, but each one has something interesting about it that makes it worth trying to find.
The first constellation is Coma Berenices, beside Leo, and above Virgo.
Although there is no bright stars to hook on to, once you know it’s there, it is straightforward to recognise as an upside down L-shape of 3 stars of about 4th magnitude.
The globular cluster M53 is very close to the brightest star in the constellation and can be seen as a small, misty patch.
The Coma Star Cluster is a nearby group of about forty 5 to 10th magnitude stars, gathered below gamma Coma Berenicis. This cluster is so spread out because it is relatively close, about 280 light years. It’s proximity to us makes this cluster important in calibrating the distance scales to astronomical objects. Different methods have given the same distance to this cluster, improving the reliability of these methods.
This constellation also contains a number of galaxies, although none of them can be see very well in binoculars. These are part of the same group as the ones in the Virgo cluster, that have spread over the border, showing that galaxies are no respectors of human boundaries.
The next constellation is Lepus, the hare. I chose this constellation mainly because it is right underneath Orion, and it pretty well overshadowed by it.
The main constellation is not a simple shape to see, but the quadrilateral of the four brightest stars is reasonably easy to find.
At the very edge of the constellation, the star R Leporis is a very deep red variable, called Hind’s Crimson Star. This is a so called carbon star, with an atmosphere that has more carbon atoms than oxygen atoms. It is these extra carbon atoms that give the very deep red colour.
Because this star is variable, it can be difficult to see, as it changes between about 6th magnitude to 10th magnitude over a period of 14 and a half months. And it is at its red-est when it is faintest, and most difficult to see.
The third constellation is Sagitta, the arrow, and is the third smallest in the sky.
It’s not a bright constellation, the stars are around 4th magnitude, but part of its charms it that it’s clearly in the shape of an arrow, and has been recognised as a constellation in writings as far back as the 2nd century AD.
Since Sagitta sits inside the summer triangle of Deneb, Vega and Altair,it covers part of the Milky Way and is rich in stars which makes a lovely backdrop to any constellation. Also along the shaft of the arrow is M71, a young globular cluster of about 6th magnitude, and is seen as a rounded misty patch in binoculars.
The last constellation is maybe a little bit of a cheat. It’s not actually small, in the same way as the others, but it is faint, and easily overlooked. And it’s also one of my favourites.
It’s the constellation of Vulpecula, the fox. It’s just above Sagitta, so it lies partly inside the summer triangle and across the Milky Way. It was originally the fox and goose, with the goose being represented by the brightest star in the group, Anser.
All the stars are 4th magnitude or less, so like the others it’s not an obvious constellation. But there are two objects in particular that make this a good target to view in binoculars.
The first is a planetary nebula, M27, the Dumbbell nebula. This is seen as a faint greenish patch in binoculars, about a quarter of the diameter of the moon, although the double lobed, dumbbell shape is seen better in photographs or through larger telescopes.
The other good target in Vulpecula is the cluster named Collinder 399. Its stars are not physically linked, but the ten brightest stars in the group, about 6th or 7th magnitude, form an interesting shape in the sky, an upside-down coathanger.
So we have looked briefly at four small constellations. They are all inconspicuous, but there are some interesting and unusual objects in them that are well worth taking a look at with binoculars.
I hope you have enjoyed this podcast. Thank you for listening.
End of podcast:
365 Days of Astronomy
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