Adrian Dening's
Stars Over Somerset

 

 

My weekly articles about what can be seen in the night sky over Somerset are broadcast every Thursday to Sunday at various times, on Yeovil's local community radio station Radio Ninesprings.
 
BBC Somerset also transmit the articles on Luke Knight's Friday evening show.
 
 
Please click on the link below to hear the interview that I gave BBC Somerset:
 
Adrian Dening & Luke Knight Interview MP3
 
 
Update January 2022..........I'm delighted to announce that Apple FM in Taunton are now also carrying the broadcasts :-)
 
 
 
Update February 2022..........The word is spreading..........I've just been asked if the articles can also be published in the Limington News which is a monthly local village publication.

 

 

Monday 4th to Sunday 10th July 2022
 

Last week I talked about the constellation of Sagittarius that can be found close to the south horizon after midnight.  I also suggested that if you have access to binoculars or a telescope, then you could try spotting Messier 8, the Lagoon Nebula.

 
 

Just above the Lagoon Nebula is another great target - the Trifid Nebula, also known as Messier 20.  The name does not originate from any science fiction story, but means "three lobes" and M20 is an unusual combination of emission nebula where stars are born, a reflection nebula where spent gas is illuminated by the stars nearby and a dark nebula where the cloud is so dense that it absorbs the light coming from behind it.  For good measure, there is also an open cluster of stars within it.

 
 
The Trifid Nebula is estimated to be 4100 light years away from us and with a magnitude of around 6, binoculars or a telescope will be needed to see it.  You will observe a fuzzy blob, so I have provided a photograph below that better-shows M20's complex details, courtesy of the European Southern Observatory in Chile.
 
 

I suppose I should wish everyone a "Happy Aphelion Day" for Monday 4th July!  Just like the Moon's orbit around us has a Perigee and Apogee when it is slightly closer or further away from us, so does our orbit around the Sun.  The 4th July is "Aphelion" when we are the furthest we get from the Sun during our year-long orbit around it.  At that point, we are 152 million Km or 94.5 million miles from the Sun.  Perihelion occurs in January and then we are about 5 million Km or 3 million miles closer.  Doesn't feel like we are closer though!

 

 

Monday 27th June to Sunday 3rd July 2022
 

The end of June is an ideal time to see a teapot with steam coming out of the spout!  Have I gone completely mad?  I'd better explain..........

 

There are 88 official constellations of stars recognised by the International Astronomical Union.  They all have familiar names like Orion that are tied back to ancient mythology - Orion was the Hunter.  Another such constellation is Sagittarius, whose name is derived from the Latin word for an archer with a bow and arrow.

 

If you look towards the south after midnight, Sagittarius will be close to the horizon.

 
 
 

Other patterns of stars that are easy to spot, but are not official constellations are called "asterisms".  Within Sagittarius is the "teapot" asterism, so named because it looks like a teapot with the handle to the left and spout to the right.  From a dark sky location, it is possible to see the Milky Way that resembles faint cloud - actually millions of very distant stars in our galaxy.  This cloud looks like steam coming out of the teapot.

 

Just above and to the right of the teapot's lid is a treat for binocular or telescope users - the Lagoon Nebula that is also known as M8 in the Messier Catalogue.  M8 is classed as an emission nebula where ionised Hydrogen gives birth to new stars.  The nebula is estimated to be between 4000 and 6000 light years away from us and even with simple binoculars it should be possible to make out a distinct patch of fuzzy cloud with a bright centre.

 

 

 

Monday 20th to Sunday 26th June 2022
 

There is a very special event taking place on the morning of Friday 24th, but you will need to be up early, around 4am, to catch it.  It really will be worth the effort - so long as it's not cloudy.

 

If you look towards the east at that time, there is an opportunity to see all seven of our neighbouring planets at once!  They will form a line running either side of due east.

 

From left to right..........Mercury very close to the horizon, Venus, Uranus, Mars, Jupiter and Neptune, with Saturn slightly further to the right.  Uranus and Neptune will be too dim to see with the naked eye, so you will need binoculars or a telescope to be able to find them, but the others are easy to spot.  As if that wasn't enough, a Crescent Moon will be in the middle of the line-up as well.

 
 

Hang on..........at school I was taught that there were nine planets in the Solar System, not seven.  Well of course you are stood on one of them - Earth.  Little Pluto was "downgraded" to a minor or "dwarf" planet by the International Astronomical Union back in 2006.  It was originally discovered by an American astronomy student called Clyde Tombaugh in 1930.  Pluto lives in the Kuiper Belt that contains many objects orbiting the Sun at a greater distance than Neptune and the problem started when during the 1990s we started to discover quite a few large objects out there and there aren't enough Disney names to cover them all!

 

Technically, Pluto is classified as a dwarf planet because it does not have enough mass to have cleared the space immediately around it from other debris.

 

 

Monday 13th to Sunday 19th June 2022
 

Nothing in space is a perfect circle.  The orbits of planets around the Sun are all elliptical or "egg shaped" to a greater or lesser degree.  The same is true for the Moon that orbits around us.

 

The Moon takes just over 27 days to complete one orbit and at different times it is slightly closer and further away from the Earth.  The closest it ever gets is 363,000 Km or 225,000 miles in old money and this point is called "Perigee".  The furthest point is called "Apogee" and then it is 405,000 Km or 251,000 miles away from us.  If you forget which is which, just remember that at Apogee, the Moon is "apologising" for being so far away!

 

On the evening of Tuesday 14th there is a Full Moon.  If you go outside a little before 11pm, the Moon will be rising over the horizon towards the south east.  This particular Full Moon is known as a "Supermoon" because it occurs near Perigee when the Moon is closest to us.

 
 
There is also an optical effect called "Moon Illusion" which occurs when the Moon is close to the horizon - your eyes and brain play a trick on you and make the Moon seem artificially large.
 
Of course, a bright Full Moon is the ultimate source of light pollution, so it is not the best time to go hunting for faint deep sky objects, but it is a great chance to spot some of the larger, more obvious lunar features.
 

Most will be visible without even resorting to binoculars or a small telescope.  In fact, you are better off not using a telescope because a Full Moon can be painfully bright without a special filter in your eyepiece.

 
 
Image courtesy of Wikipedia

 

 

Monday 6th to Sunday 12th June 2022
 
On the evening of Thursday 9th, the Moon will be a couple of days past its First Quarter phase and this is a great opportunity to spot one of the more unusual Lunar features known as the Hortensius Dome Field.  At around 11pm, the Moon will be situated towards the south west.
 
 

Firstly find the large crater Copernicus.  Looking at the nearside face of the Moon, it is slightly to the left of centre and is quite easy to see without resorting to a telescope or binoculars.

 
 

To the left of Copernicus is the much smaller crater Hortensius.  It is an impact crater with a diameter of only 15Km, so best to dig your telescope out at this point!

 
Just above the crater are six lumps in the Lunar surface - these are called the Hortensius Domes.  The four larger ones have been named with Greek letters, the smaller two have never been named.  Some of them have a dimple at the top which is given the cute term "craterlet".
 
 
 
Images courtesy of Znith Observatory
 

The domes are evidence of volcanic activity in the Moon's distant past and they were formed by a highly viscous type of lava.  Calling them domes isn't very technical and the correct term is "shield volcanoes", so named because they have a low profile and are meant to look like an ancient Greek warrior's shield lying on the ground - how technical is that!!  Shield volcanoes are found on other planets in the Solar System, including our own.  The best example is Mauna Loa on Hawaii and I have included a photograph of it in case you've never been there!

 
 
Photograph courtesy of Wikipedia

 

 

Monday 30th May to Sunday 5th June 2022
 

After their conjunction last week, there are still some great opportunities to see Mars and Jupiter close together, but you will need to be an early riser.  Just before daybreak, say around 3.30am, the pair of planets will be located towards the east, fairly close to the horizon.

At the same time, Saturn will be slightly higher up, towards the south east.

 
 

If you are up at that time of day and fancy a little challenge with your telescope or binoculars, you could have a go at spotting one of Charles Messier's globular star clusters, M14.

 
First find the large constellation of Ophiuchus slightly west of due south.  It resembles a large box with a pointed lid and the bright star, Rasalhague, is at the top.  Then locate the two stars Cebalrai and Sabik running down the left hand side of the constellation.  M14 is situated approximately one third of the way down from Cebalrai and slightly to the left. 
 
 
 

The cluster is about 30,000 light years away, so if you do go outside to observe it, you will be seeing the cluster how it was 30,000 years ago because the light has taken that long to reach us!  The cluster contains several hundred thousand stars - with binoculars or a small telescope, it will resemble a fuzzy blob.  You would need a large telescope to be able to start resolving individual stars within it.

 
The name Ophiuchus comes from the ancient Greek word meaning "serpent bearer" and he is holding a snake, represented by the adjacent constellation of Serpens.
 

 

 

Archived Articles
 
May 2022
 
April 2022
 
March 2022
 
February 2022
 
January 2022
 
December 2021
 
November 2021
 
October 2021
 
September 2021
 
August 2021
 
July 2021

 

 

Screenshots courtesy of Stellarium

 

Copyright Adrian Dening and Radio Ninesprings 2022

 

To enquire about local astronomy talks and star parties
please contact Adrian Dening
 
07545 641068
info@starsoversomerset.com

 

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