Adrian Dening's
Stars Over Somerset

 

Latest News Latest News

 

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 5th to Sunday 11th December 2022
 

It's a period of occultations!  Sounds like a series of sinister black magic ceremonies are going to be taking place, so I'd better explain..........

 

In astronomical terms, an "occultation" occurs when one celestial body appears to pass in front of another, temporarily blocking it from our view.  Next week, the Moon is the culprit, with Uranus and then Mars being the victims.

 

Firstly, between 4.50pm and 5.20pm on Monday 5th, the Moon (that will be located towards the east) will occult Uranus.  It will take about 20 seconds for the Moon's north west edge or "limb" to cover the planet and the same time for it to reappear behind the Moon's north east limb half an hour later.  In other words, the northern area of the Moon's surface will appear to hide the planet.

 
 
 

Of course, Uranus is a small target for your telescope or binoculars, currently shining at a magnitude of only +5.6 and the Moon will be almost at its full phase, so creating a lot of light pollution.

 
If you are up early on Thursday 8th around 4.50am and look towards the west, you can catch the Full Moon occulting Mars.  The Red Planet will take 37 seconds to disappear behind the north west limb of the Moon at 4.57am and 37 seconds to reappear from behind the south east limb a whole hour later.
 
Because Mars is so bright, shining at a magnitude of -1.9, the event can even be viewed with the naked eye!
 
 
 

In a twist of fate, Mars reaches opposition, when it is at its absolute brightest, while it's behind the Moon at 5.36am that morning!

 

 

Monday 28th November to Sunday 4th December 2022
 

It really is the best time to aim your telescope towards Mars as the planet is only one week away from opposition, when it will be at its very brightest.  Next week, it will be shining at a magnitude of around -1.8 and if you are outside around 9pm, the planet will be located towards the east, a little above the constellation of Orion and below the Pleiades open cluster of stars.

 
 

Also Mars reaches an altitude of 60 degrees in the sky which provides better viewing as the light reflecting from the planet's surface is entering our atmosphere at a sharper angle and so travels through less of it to reach your eyes.  When an object is lower in the sky, the light travels through a thicker layer of atmosphere and this distorts everything.  It's the same reason why stars twinkle - they don't really, but the faint light coming from them gets scattered as it travels through our air.

 

Some stars do vary in brightness though.  Look to the left of the Pleiades and find the constellation of Perseus.  Then identify the star Algol, also known as the "Demon Star".  It is actually an eclipsing binary star system where two stars orbit around each other.  The pair normally has a steady magnitude of +2.2, but every 2.86 days it drops to +3.4 as one star appears to pass in front of the other over a period of ten hours.

 
 

An ancient Egyptian calendar of lucky and unlucky days, composed 3200 years ago, is the earliest known documentation of Algol's discovery and they associated it with a demon-like creature.

 

 

Monday 21st to Sunday 27th November 2022
 

Any evening next week, look high up towards the south east and spot the constellations of Cassiopea (the famous "W" shape) and Perseus.  Half way between the two constellations is a pair of open star clusters known as the Double Cluster.

 
 

The clusters have a magnitude of around +3.8 so should be visible to the naked eye if you are in a nice dark location, but binoculars or a small telescope would be better.  They are 7500 light years away and in astronomical terms, they are youngsters, being only 14 million years old!  By comparison, the Pleiades open cluster is between 75 and 150 million years old!

 

Time for a quick astronomy lesson.....the Double Cluster is known as a "circumpolar" object.  This means that from high latitudes here in the northern hemisphere, it can been seen all through the hours of darkness, all through the year.  Or if you prefer it in simple terms - it is just very high in the sky, like the pole star that everything appears to rotate around.

 

Last week I spoke about an opportunity to witness one of Jupiter's moons - Ganymede - disappearing behind the planet while another of its moons -Europa - casts a shadow on the planet's surface as it passes in front of the gas giant.  If you miss that event on Sunday 20th, don't worry because the exact same scenario repeats on the evening of Sunday 27th, but slightly later from 9pm.

 

Aim your telescope towards the south west and Jupiter will be very obvious, shining at a magnitude of -2.6 while further to the west, Saturn will be getting close to the horizon and appearing a little dimmer.

 

 

 

Monday 14th to Sunday 20th November 2022
 

The evening of Thursday 17th into the early morning of Friday 18th sees the peak of the Leonids meteor shower.  By midnight on the Thursday night, the constellation of Leo the Lion will have risen above the horizon towards the east and the radiant point, where the shooting stars appear to originate from, is just above the stars marking the lion's head.

 
 

The zenithal hourly rate is around 10 meteors per hour and the fast-moving streaks of light are created by particles left from comet Tempel-Tuttle, some as small as a grain of sand, entering the Earth's atmosphere at speeds of up to 70 kilometers a second.

 

By 1am on the Friday morning, a 33%-lit waning Crescent Moon will have also risen above the horizon in the east and the light pollution from it will then spoil your viewing somewhat.

 

Officially, planet Jupiter has 80 moons orbiting around it and 57 of them have been given names by the International Astronomical Union.  The four largest - Io, Europa, Ganymede and Callisto - are known as the Galilean moons because they are the ones that Galileo first saw in his telescope back in 1610.  With binoculars or a small telescope, you can sometimes see all four of them, but on other occasions one or two appear to be missing because their orbit takes them behind the planet.

 

If you aim your telescope south east towards Jupiter just after dark, at 5.30pm on Sunday 20th, you will catch Ganymede disappearing behind the planet while Europa casts a shadow on the planet's surface as it passes in front of the gas giant.

 
 

 

 

Monday 7th to Sunday 13th November 2022
 

I'm going to suggest a little adventure for telescope users, but you will need to be up around 5am on Monday 7th.  The reward for such an early start is the chance to observe a collection of distant galaxies and the dwarf planet Ceres which is the largest object in the Asteroid Belt.

 

First find the constellation of Leo the Lion towards the south east.  Then locate the bright star Chertan which is in the vicinity of the lion's bottom!  A little below Chertan is a group of three galaxies, known as the "Leo Triplet".

 
 
 
 

These three spiral galaxies are named M65, M66 and NGC3628.  They have magnitudes between +9.0 and +10.0 because they are over 35 million light years away!  If you look at them in your telescope, you are seeing these deep sky objects how they were 35 million years ago because their light has taken that long to reach us!

 
If you imagine these three galaxies as marking three corners of a square, dwarf planet Ceres will be marking the 4th corner, shining at a similar magnitude.
 
 

There is a further opportunity to observe two of Jupiter's moons, Europa and Ganymede, transiting across the face of the planet between midnight and 1.30am on the morning of Thursday 10th.  At that time, Jupiter will be located towards the south west.

 
 

Finally, a couple of dates for your diary.  As my last astronomy lectures at Ham Hill sold out so fast, I have managed to agree two further evenings on 27th January and 17th February next year.

 

 

Monday 31st October to Sunday 6th November 2022
 

This month, Mars makes a great target as it approaches opposition when it will be at its brightest.  This coming week the Red Planet will be located towards the east if you go outside around 10pm and shining at a magnitude of around -1.3 which is pretty bright - a similar brilliance to Sirius which is the brightest star in the night sky.

 
 

You could go outside a bit earlier after it's become dark to see Mars, but then it will be lower in the sky and won't look so good in a telescope as the light reflecting from the planet's surface will be passing through more of our atmosphere and this distorts the light waves.

 

At the same time, you could look to the right of Mars to see the constellation of Orion, with the constellation of Taurus above it and the Pleiades open cluster of stars M45 above that.  Remember that the "sword" of Orion is the location of the Great Orion Nebula M42, so it would be worth aiming at that one too!

 

If you take your telescope out just before 9pm on Wednesday 2nd there is a chance to see two of Jupiter's moons, Europa and Ganymede, transiting across the face of the gas giant.  Jupiter will be located towards the south, with the Moon to the right of it and Saturn further right again.  Our Moon will have just gone past its First Quarter phase so will appear as a waxing Gibbous Moon.

 
 

Of course when you've had enough of watching Europa and Ganymede, you could have a go at Saturn's rings and then turn your telescope towards the east to view Mars that will be nice and high in the sky by then.

 

 

Monday 24th to Sunday 30th October 2022
 

The big news is a partial solar eclipse taking place on Tuesday 25th between 10am and midday.  The maximum effect will be seen around 11am.  Observers in the north of England will have the best view at a magnitude of 35%, but it will still be worth going outside to see it down here in the south west where the magnitude will be 17%.

 
 

Eclipse diagram courtesy of Pete Lawrence, Sky at Night Magazine

 

Nothing in science and especially astronomy is simple and the term "eclipse magnitude" has nothing to do with how bright it is, rather how far the eclipsing body extends over the diameter of the object being eclipsed.  In other words, if the Moon's edge reached the middle of the Sun's disc, then the eclipse magnitude would be 50%.  A total eclipse would be 100%.

 

Talking about brightness, please remember that you must never ever look at the Sun through a telescope or binoculars - even the quickest glimpse will result in permanent blindness.  Also I wouldn't be temped to use those old solar viewing glasses that were mass-produced for the 1999 total eclipse - they are not the best quality to start with and may have been damaged in storage.

 

So how do you look at it?  In the absence of a dedicated solar telescope costing thousands of pounds, the safest method is to use a technique called "pinhole projection".  Let the Sun shine through the holes of a colander from the kitchen.  Place a piece of white card a little distance underneath it or hold the colander near a while wall and you will see multiple images of the eclipse projected onto the card.  On a smaller scale, you could even use one of those old metal tea strainers.

 

 

 

Monday 17th to Sunday 23rd October 2022
 

If you go outside after 10pm on Monday 17th, the constellation of Taurus will have risen above the horizon in the east, with the Pleiades open cluster of stars above it.  Planet Mars will be to the left of Taurus.

 
 

Approximately half way between Mars and the star Zeta Taurus (which is the constellation's bottom left star) you can find the Crab Nebula.  It was the first deep sky object that Charles Messier catalogued and is therefore also known as M1.  The nebula has a magnitude of +8.4 so is too faint to be seen with the naked eye.  A telescope or binoculars should reveal a fuzzy blob that is estimated to be between 5000 and 8000 light years away from us.

 
 

The astronomer John Bevis first spotted the fuzzy blob in 1731 and Messier catalogued it a few decades later.  In 1842, William Parsons who was the 3rd Earl of Rosse, used his large 36 inch telescope to draw the nebula and his sketch looked a bit like a crab - hence its common name.  The nebula contains the remnants of a supernova that the ancient Chinese observed in 1054.  In the centre is a neutron star that emits loads of x-ray and gamma radiation.

 
 
 
Crab Nebula images courtesy of Wikipedia
 

Moving towards the end of the week and a bit closer to home, the evening of Friday 21st sees the peak of the Orionids meteor shower, so named because the radiant point where the meteors appear to originate from is in the constellation of Orion close to the star Betelgeuse.  As you approach midnight, Orion will have risen above the horizon to the east.  The meteors are produced as the Earth passes through the dust left by comet Halley.  The shower has a zenithal hourly rate of around twenty meteors per hour and a lack of Moon in the night sky that evening gives the best chance of seeing some.

 

 

Monday 10th to Sunday 16th October 2022
 

Last week I talked about a waxing Gibbous Moon - waxing because it was getting brighter as it headed towards a Full Moon.  Now we are past the Full Moon, it appears as a waning Gibbous Moon.

 

If you go outside around 5am on Wednesday 12th, a 94%-lit waning Gibbous Moon will be towards the south west, with planet Uranus a little above it and to the left.  Uranus will have a magnitude of about +5.6, so in theory at least, it could just be visible with the naked eye from a very dark location, BUT there will be light pollution from the Moon meaning that you should really dig out those binoculars or a small telescope.

 
 

If you aim towards the south instead, you will see the constellation of Orion with planet Mars above it.  Half way between Mars and the Moon will be the Pleiades open cluster of stars sitting just above the constellation of Taurus that has the bright star Aldebaran in it.

 
 

There are several interesting astronomical events coming up later this month, including the Orionids meteor shower and a partial eclipse of the Sun, but for now I am going to make another blatant advertisement for the two astronomy lectures and star parties that I am running at the Ham Hill Visitor Centre.  They are taking place on Friday 21st October and Friday 18th November, with a talk at 7pm, followed by refreshments at 8pm before we venture outside to have a look at the night sky.

 

Booking is essential as places are limited and you can do this via the  www.visitsouthsomerset.com  website or by scanning the QR code on the posters below.

 
 

 

 

Monday 3rd to Sunday 9th October 2022
 

If you venture outside just after dark on Wednesday 5th, there is an opportunity to see Saturn with an 80%-lit waxing Gibbous Moon just below it.  By around 9pm, the pair will be located towards the south.

 
 

If you go back outside at the same time a few days later, on Saturday 8th, then a 98%-lit waxing Gibbous Moon will be towards the south east, just below Jupiter.

 
 

The Full Moon occurs the following evening, on Sunday 9th.  When talking about the phases of the Moon caused by Sunlight hitting its surface at different angles as it orbits around us, "waxing" and "waning" are old English words meaning "getting stronger or increasing in brightness" and "becoming weaker or decreasing in brightness".  So the Moon is "waxing" as it heads towards a Full Moon when it is then 100%-lit and "waning" as it moves towards a New Moon.

 
 
Diagram courtesy of Wikipedia
 

If early morning astronomy is more your thing, then there are several treats awaiting you around 6am on Saturday 8th.  To the east, Mercury will be rising above the horizon.  The planet is at its greatest elongation or in other words, the furthest it gets away from Sun.  At the same time, the constellation of Orion with Betelgeuse and Rigel will be towards the south, with the brightest star in the night sky, Sirius, just below it and planet Mars a little above the constellation.

 
 

Please remember that if you are tempted to use binoculars or a telescope to get a better view of Mercury, you must be very careful that you do not catch even a glimpse of the Sun as it rises shortly afterwards!

 
To learn more about the Moon's phases or general astronomy, come along to one of my Stars Over Somerset lectures at Ham Hill on 21st October and 18th November.
 
 

 

 

Archived Articles
 
August - September 2022
 
June - July 2022
 
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

 

Designed for 1024 x 768 resolution