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

 

Monday 13th to Sunday 19th December 2021
 

The main astronomical event is the peak of the Geminid meteor shower with the best opportunity being the early hours of Tuesday morning 14th.  There is a 78%-lit Gibbous Moon creating some light pollution, but it sets around 3am, giving you a few hours of dark sky before sunrise.

 

The Geminids is so named because the radiant point where the meteors appear to originate from is in the same area of the sky as the constellation of Gemini, "The Twins".  The radiant point is near the bright star Castor which marks the head of the right hand twin.  If you get up early, around 4 - 5am, Gemini will be located towards the south west.

 
 

The debris that is creating the shooting stars is from an asteroid, which is unusual as most meteor showers are caused by debris from comets.  As a result, the debris contains traces of metals and this can create different colours as it burns up in the atmosphere.  We use the same principle to make fireworks colourful.

 

At the beginning of the year, a new comet was discovered.  C/2021 A1 is also called "Leonard" after the astronomer who first found it.  The comet is currently to the lower right of Venus which sets below the south west horizon shortly after sunset.  Telescope users should be able to see the comet's tail and it is hoped that it may even be visible to the naked eye.

 

Below is a diagram showing the comet's location through the rest of December, courtesy of Sky at Night Magazine, along with a photograph of the comet taken by astronomer Jose Chambo.

 
 

 

 

Monday 6th to Sunday 12th December 2021
 

At the moment, the early evening sky presents a great view of the planets Venus, Saturn and Jupiter when you look towards the south.  If you do this around 5pm on Tuesday 7th, a 16%-lit Crescent Moon is also added into the equation.

 
 
It's a brilliant time to get youngsters out in the garden with a telescope as potentially you can see the Galilean Moons of Jupiter, the rings of Saturn, Venus as a crescent and the Moon all in one hit without even having to stay up late and get too cold!
 

A few weeks ago I mentioned a series of visual effects on the Lunar surface known as "clair-obscur".  Later next week there is the opportunity to see two of them..........

 
Firstly, around 8.30pm on Saturday 11th, it is possible to observe the effect known as "The Face of Albategnius" which looks like the profile of a face in the crater with the same name. 
 
Then, around 10.20pm on Sunday 12th, "The Eyes of Clavius" can be seen as the Lunar dawn breaks over the crater Clavius.
 
 
While you are looking at the Moon, I thought it might be fun to spot where the Apollo missions landed over fifty years ago.
 

 

 

Monday 29th November to Sunday 5th December 2021
 

Venus was the Roman goddess of love.  It is also the name of the second planet in our Solar System.  Venus is sometimes described as our "sister planet" because it has a similar size and mass to the Earth.

 

Venus is certainly beautiful to observe - it is the brightest object in the night sky next to our Moon and a telescope will reveal that it has different phases, just like the Moon.

 

However, that's where any connection between Venus and love stops!  Venus has a thick toxic atmosphere of Carbon Dioxide with clouds of Sulphuric acid.  The clouds trap heat and the surface temperature is around 475 degrees Celsius.  This results in very high atmospheric pressure - about 90 times that of the Earth or the equivalent to being a mile under the ocean!  So if you travelled to Venus in your spaceship, you would be eaten by acid, cooked and crushed to death, but not necessarily in that order!  Lovely!!

 

Next week you can observe Venus from the safety of your back garden though as the planet is currently at its brightest.  Look towards the south west just as it's getting dark and the planet will be setting in a line with Saturn and Jupiter above and to the left of it.  Using a telescope will reveal a wonderful crescent shape, but if you're doing that, please make sure that your telescope is not pointing anywhere near the setting Sun - please wait until the Sun has completely disappeared below the horizon!

 
 

 

 

Monday 22nd to Sunday 28th November 2021
 

Ceres is the largest object in the Asteroid Belt that orbits between Mars and Jupiter.  It was the very first asteroid discovered there back in 1801.  It has a diameter of almost 1000Km and as a result, it was originally classified as a planet.  By the 1850s, lots more asteroids had been found so Ceres was re-classified as a "big asteroid"! 

 

Then in 2006 the International Astronomical Union had a big debate about the definition of a planet.  Pluto was re-classified as a "dwarf planet" and at the same time, Ceres became one of those too!

 

Ceres is usually very difficult to locate in the night sky and because of its size, never reflects enough light to be seen with the naked eye.  Next week it happens to be at its brightest, around a magnitude of +7, so you should be able to see the dwarf planet with binoculars.

 

To find Ceres, from about 8pm, look to the east and locate the constellation of Orion.  Draw an imaginary line from Orion's Belt up towards the Pleiades cluster and half way along is the constellation of Taurus.  As well as containing the bright star Aldebaran, the centre of Taurus contains the Hyades open cluster of stars and Ceres is currently located between two of those stars - Hyadum I and Hyadum II.

 
 
 

The best evening to try is Saturday 27th when Ceres is at opposition or in other words, closest to the Earth and at its very brightest.

 

 

Monday 15th to Sunday 21st November 2021
 

We'll start the week with a bit of a challenge - have a go at trying to find the planet Uranus.  If you look directly east at 6pm on Monday 15th, the planet will be located to the right and slightly up from the constellation of Taurus and the Pleiades cluster of stars.

 
 

The planet currently has a magnitude of around 5.7 so it should be possible to spot it with binoculars.  Using a telescope will reveal its turquoise colour.

 

Uranus is the seventh planet from the Sun, 2 billion miles away and the planet takes 84 years to orbit the Sun where we only take 365 days!  It is composed mainly of Hydrogen and Helium and is the coldest planet in our Solar System with a minimum temperature of -224 degrees Celsius.

 

William Herschel discovered Uranus back in 1781.  It had been observed many times before then, but everyone thought it was a star.  The Voyager 2 space probe imaged the planet in 1986 and revealed it to be almost featureless with none of the storms or bands of clouds associated with the other gas giants.  Uranus is unique in that it spins on its side or in other words, its north and south poles are actually east and west!

 

The morning of Friday 19th sees a Full Moon and partial Lunar eclipse.  If you look to the west from about 6am, the Moon will be setting and partially eclipsed by the Earth's shadow.  The effect is most noticeable from 7am, just before moonset.

 

 

 

Monday 8th to Sunday 14th November 2021
 

On Monday 8th if you look towards the south west horizon around 6pm, after the Sun has set, there is the chance to see a bright planet Venus shining at magnitude -4.4 slightly to the right of an 11%-lit Waxing Crescent Moon.

 
 
 

The following evening, Tuesday 9th, telescope users have the chance to spot the shadow of Ganymede, one of Jupiter's moons, transiting across the planet's disc.  You'll need to be aiming at Jupiter towards the south just after it gets dark and you will have to be quick as the event is all over by 6.40pm.

 
 
 

A couple of weeks ago I mentioned "clair-obscur" visual effects when observing the Moon.  On Thursday 11th there is the opportunity to see two of these effects known as the Lunar "V" and "X".  They are most visible from around 10.30pm just before the First Quarter Moon sets in the south west.

 
 
 
To help you find them, below is a map of the different clair-obscur effects and photographs of the "V" and "X" courtesy of Sky at Night Magazine and Pete Lawrence.
 
 
 
 
 
 
 

Finally, the night of Thursday 11th into the morning of Friday 12th sees the peak of the Northern Taurids meteor shower.  Best viewing is from midnight, so really the early hours of the Friday morning.  The radiant point of the shower is right of Taurus and the Pleiades cluster, towards the south if you start looking from midnight.

 
 
The shower has an hourly rate of only five meteors, but the trails look very bright because they are travelling relatively slowly at only 65,000 miles per hour!

 

 

Monday 1st to Sunday 7th November 2021
 

When you look at the Moon, one of the most obvious features are the dark, flat areas that early astronomers used to think were seas or oceans.  Probably the most famous is Mare Tranquilitatis or the Sea of Tranquility where Apollo 11 landed back in 1969 and Neil Armstrong took his first steps.

 

The Moon's orbital period around us and its rotational period are the same - this means that the same side of the Moon is always facing us and the "dark side" is always pointing away from the Earth.  The Moon also experiences "libration" which is best described as a small rocking motion, so sometimes you can see a bit further round what is normally the dark side.

 

Monday 1st November gives you the opportunity to try spotting the Mare Orientale or Eastern Sea, confusingly located on the western edge of the dark side.  It is an impact basin, created by an asteroid hitting the Moon about 3 billion years ago.  When viewed from above it resembles a bull's-eye, but you will only be able to see it almost sideways-on.

 

The 17%-lit Crescent Moon rises above the horizon in the east a little before 3am on 1st and to make it easier to find Mare Orientale, I have added a diagram showing its location courtesy of Wikipedia and an image of what the bull's-eye looks like from overhead, courtesy of NASA and their Lunar Orbiter 4 space probe.

 
 
 

 

 

Archived Articles
 
October 2021
 
September 2021
 
August 2021
 
July 2021

 

 

Screenshots courtesy of Stellarium

 

Copyright Adrian Dening and Radio Ninesprings 2021

 

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

 

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