I'll start next week's report with the evening of Tuesday 12th, when it is the turn of Ganymede to be occulted by Jupiter.  If you look towards the south east at 8pm, the Galilean moon will be just about to disappear behind the planet.

Moving on to the night of Thursday 14th into the early hours of Friday morning 15th, we have the peak of the annual Geminids meteor shower.  Around midnight, the constellation of Gemini will be located towards the south east with the familiar shape of the "Twins" looking as if one is above the other.  The radiant point of the shower, where the meteors seem to originate from, will be a little above the bright star Castor which marks the head of the top twin.

Staying with the astronomical theme of observing objects appearing to be on top of one another, at 7.30pm on Sunday 17th, a 27%-lit Waxing Crescent Moon will be sitting just below a magnitude +0.8 Saturn if you look towards the south west.

An hour and a half later, at 9pm, the Galilean moon Callisto will be directly below Jupiter's south pole if you turn your telescope towards the south.  You should be able to see all four of the Galilean moons simultaneously, forming a line stretching away from the planet.

If you try doing that, be careful as you will be making the same observation that Galileo did back in 1610, when he realised that our Solar System was "Heliocentric" with the Sun in the middle - an observation that found him to be "vehemently suspect of heresy" and placed under house arrest for the rest of his life!

I've spoken several times recently about "transits" where one of Jupiter's moons passes in front of the planet, casting a shadow.  On the evening of Thursday 7th there is an opportunity to see the opposite effect - an "occultation" where a moon passes behind the planet and is obscured from our view.

It will reappear again from behind the other side of Jupiter just after midnight.

If you would prefer an early morning, a little before daybreak, say around 6am on Saturday 9th, a 14%-lit Waning Crescent Moon will be visible towards the south east, with Venus just to the left of it, shining very brightly at a magnitude of -4.0 so an excellent chance to observe it.

Remember that the magnitude scale works back-to-front, so the more negative the figure, the brighter an object appears.  With the naked eye from a dark location, you can see down to a magnitude of +6.0 and anything fainter than that needs binoculars or a telescope.  The brightest star in the night sky, Sirius, has a magnitude of around -1.4 so it is very easy to see.  To put that into perspective, our Sun (which doesn't really count because you don't see it in the NIGHT sky) would have a magnitude of -26.  That's why you NEVER try looking at it through a telescope!

It's a fairly quiet time for astronomical events during the coming week, so I'm going to take the opportunity to talk about something that has been in the news a lot lately - the Northern Lights or Aurora Borealis.

We all know that the Sun gives off loads of light, but it radiates other energy as well, including the Solar Wind that is a plasma stream of electrons and protons originating from the upper atmosphere of the Sun, an area known as the Corona.  This stream can be travelling at up to 750Km per second.

The Earth has a magnetic field around it known as the Magnetosphere.  When the Solar Wind hits our Magnetosphere, the wind creates disturbances in it and the resulting ionisation creates the amazing light that you see.

Magnetosphere diagram courtesy of Wikipedia

The disturbance is concentrated around the poles, so the visual effect is normally seen in the polar regions, but when the aurora is super strong, it can reach further down and we have a chance to observe it here in the south west of England.  Auroras around the North Pole are known as the Aurora Borealis, but there is also an Aurora Australis around the South Pole.

On a totally different subject, my astronomy talk and star party at the Ham Hill Visitor Centre in December sold out very quickly, so I have agreed two more dates for the New Year.  The dates for your diary are Friday 26th January and Friday 8th March.  Booking is via the Visit South Somerset website, accessible by clicking on the images below:

How about seeing two things at once?  Well there are a couple of opportunities to do that next week without having to stay up late.

Firstly, during the evening of Monday 20th, a First Quarter Moon will make a great target for your binoculars or telescope with Saturn just above and to the right of it.  If you venture outside around 6pm, the pair will be located towards the south.

By 11pm they will appear to have moved across the sky and will be disappearing below the horizon towards the south west.

Go outside at 6pm on Saturday 25th instead and an almost Full Moon will be located towards the east, with Jupiter just to the right of it.

The actual Full Moon occurs a couple of days later and this period is not the best for observing faint deep sky objects because a Full Moon is the ultimate source of light pollution!  The whole of November is brilliant for studying Jupiter though as it reaches a nice high elevation in the sky and is visible for most of the night, so if you can't sleep and feel the urge to whip out your telescope at 2am, the gas giant will still be there waiting for you!

Finally, there is one good opportunity to observe the International Space Station passing silently overhead on the early evening of Wednesday 22nd.  It will appear above the horizon to the west at 5.57pm and will be visible for five minutes before disappearing towards the east.  Sunlight reflecting off the ISS solar panels make it look like a bright star, except that it doesn't twinkle and it's moving!

On Monday 13th, planet Uranus reaches opposition when it will be shining at its brightest.  With a magnitude of around +5.6 it could just be seen with the naked eye from a very dark location that has zero light pollution.

If you look towards the east around 6pm, Jupiter will be easy to spot due east, with the Pleiades open cluster of stars to the left of it.  Uranus will be located half way between the two.

It may be difficult to identify the planet amongst the background stars, so I have provided a star chart to help you select the correct pinpoint of light!

The early morning of Saturday 18th sees the peak of the Leonids meteor shower, so named because the radiant point where the meteors appear to originate from is near the head of the lion in the constellation of Leo.

From 1am on the Saturday morning, Leo will have risen above the horizon towards the east.

By 4am, Leo will have moved towards the south east and a very bright planet Venus will be rising towards the east with the constellation of Virgo as its backdrop.

At its peak, the Leonids meteor shower can produce up to 12 shooting stars per hour which are debris left by comet Tempel-Tuttle entering the Earth's atmosphere at speeds of up to 70 km/s.

It looks like next week is going to be "Jupiter Week" as there are several things to spot with your telescope on what is the largest planet in our Solar System.....that's if the weather plays ball!

Firstly, from 10.20pm on the evening of Monday 6th, the Galilean moon Io transits the gas giant planet.  Underneath Io itself, you may be able to see the shadow that it casts on Jupiter's surface.  Around that time, Jupiter will be nicely placed towards the south east and very easy to spot because it is so bright.

Then from around 6pm on Friday 10th it is Ganymede's turn to transit the planet.  Because it is earlier in the evening, Jupiter will be located more to the east.

The transit will be finished by 7.45pm so then you could turn your telescope southwards to take a look at Saturn's rings.

Finally, Saturday 11th around 8.45pm is an optimum time to observe the Great Red Spot on Jupiter's surface.  Again, Jupiter will be easy to spot towards the south east, a little to the right of the Pleiades open cluster of stars.

The Great Red Spot is actually a storm in Jupiter's atmosphere that has been blowing for over 350 years with wind speeds up to 270 miles per hour.  It is about the same size as the whole of our Earth and appears to rotate around Jupiter every ten hours.  And you thought we had it bad!

Great Red Spot - Earth Comparison image courtesy of Wikipedia

On Friday 3rd Jupiter reaches opposition, when it will be at its brightest and shining at an impressive magnitude of around -2.8

By 6pm the planet will have risen above the horizon to the east and if you look to the left of Jupiter you will find the Pleiades open cluster of stars.

Aiming a telescope at Jupiter will reveal all four of its Galilean moons.  Sometimes you won't see all four of them, if one is hidden from view as it passes behind the planet.

Turn your telescope towards the south east and you will find Saturn with its dust rings.

You could even try to identify some of Saturn's numerous moons.

If instead you venture outside around 11pm on Saturday 4th, a 53%-lit waning Gibbous Moon will have risen above the horizon to the east.

Just to the right of the Moon will be the Beehive open cluster of stars, also known as M44 in the Charles Messier catalogue.  M44 is one of the closest clusters to us and it comprises around 1000 stars.  To the naked eye it will resemble a fuzzy blob, but it may be difficult to see at all without a telescope because of light pollution from the nearby Moon.

Tuesday 24th is an excellent opportunity to observe Venus as the planet reaches its greatest western elongation from the Sun, separated from it by 46 degrees.  The planet will be shining brightly at a magnitude of around -4.5 in the early morning sky.

If you look towards the east, Venus appears above the horizon from 4am and it will be very easy to spot with the naked eye.

During the evening of Saturday 28th, we have a partial lunar eclipse.  The event occurs between 8.30pm and 10pm.  At that time, the Moon will be located towards the east, a little above and to the right of Jupiter.

The main part of the eclipse, also known as the umbra, will be seen as a shadow across the southern part of the Moon's face, just below the large crater Tycho.

A lunar eclipse occurs when the Moon passes through the shadow cast by the Earth or in other words, we are blocking some of the sunlight from reaching the Moon's surface.

Finally, a reminder that British Summer Time ends at 2am on Sunday 29th.  The clocks go back an hour to 1am.  There are two bonuses - firstly we get an extra hour in bed that morning and more importantly, I don't have to keep adding an hour on to my Stars Over Somerset reports.  Astronomers, in common with many other sciences, don't bother with different time zones and summer times - they stick to the worldwide standard of UTC or Universal Time Coordinated which happens to be the same as GMT or Greenwich Mean Time which is what we use during the winter months.  Keeps it nice and simple!

Just before daybreak on Friday 20th there is an opportunity to see the shadow of two Galilean moons at the same time on the surface of Jupiter.  If you aim your telescope towards the west at 7am and find Jupiter, you should be able to see the shadows cast by Io and Ganymede simultaneously.

The late evening of Saturday 21st into the early morning of Sunday 22nd sees the peak of this year's Orionids meteor shower.  At the actual peak around midnight, you can expect to see up to 25 meteors per hour and the radiant point where they appear to originate from will be to the left of Betelgeuse, the red giant star in the constellation of Orion.  Around midnight, Orion and the shower's radiant point will be located towards the east.

The shooting stars are created by debris left behind from the famous comet Halley.  As the Earth passes through this debris on its orbit around the Sun, gravity pulls the tiny particles through our atmosphere and you see them burning up because of friction as they hit the ever-thickening air.

On Thursday 12th, comet 103P/Hartley, also known as just Hartley 2 reaches perihelion - the point when it is closest to the Sun in its orbit.

Now you normally associate comets as coming from the Kuiper Belt in the far reaches of our outer Solar System and their orbits around the Sun can take hundreds of years.

Hartley 2 is a bit different in that it actually originates from the Asteroid Belt between Mars and Jupiter.  Its orbit only takes six and a half years while it sweeps in close to the Sun and then heads back out to join its mates in the Asteroid Belt.  It is known as a "Jupiter-family" comet because of this.

The comet is peanut-shaped and only has a diameter of about one mile.  You will need binoculars at least to see it as the magnitude will be around +8.5

So how do you find it?  Venture outside after 1am on the morning of 12th and look towards the east.  You will see the obvious constellation of Orion.  To the left of Orion is the constellation of Gemini, the "Twins", who will appear to be lying on their side.

Locate the star "Wasat" which marks the waist of the lower twin.  Comet Hartley 2 will be situated just below Wasat with the comet's tail pointing towards the star.

I have provided an image of the comet, courtesy of NASA, but this was taken from only 435 miles away by their Epoxi mission in 2010.  You will see a fuzzy blob!  The good news is that the Moon will be below the horizon and so not creating any light pollution!

We're going to concentrate on Jupiter's moons as during the coming week, there are several transits where one of the moons passes in front of the planet, casting a shadow.

If you zoom into Jupiter with your telescope it will be possible to see all four of the Galilean moons, from left to right - Ganymede, Europa, Io and Callisto.  Look closely at Jupiter and you should see Europa's shadow on the surface of the planet.

If you prefer not to stay up so late, try around 10.30pm on Thursday 5th and you will be able to catch Ganymede's shadow near Jupiter's south pole.  At this time, Jupiter will be more towards the east.

Should you then decide to stay up really late and follow Jupiter, from 3am on the Friday morning, it is Io's turn to cast a shadow.

The shower is so named because its radiant point appears to be in the same part of the sky as the constellation of Draco.

Finally, I have just agreed to run another couple of my popular astronomy evenings at the Ham Hill Centre this autumn.  Booking information will be available soon, but in the meantime the dates for your diary are Friday 27th October and Friday 15th December.

The evening of Monday 25th is an ideal time to spot the impact crater on the lunar surface known as Vitello.  If you venture outside around 10pm, a Gibbous Moon will be located to the south, with Saturn a little above it and to the left.

Imagine the face of the Moon as a clock, Vitello will be located towards 7 o'clock, on the southern shore of Mare Humorum.

Vitello location map courtesy of IAU Working Group for Planetary System Nomenclature

The crater has a diameter of 41Km and is around 4 billion years old.  A telescope will reveal that it has a mountain complex in the centre and a very well-defined outer edge or rim.  The craters neighbouring it are not so clear because they filled with lava, but Vitello has an elevated position, so its rim and floor were left intact and not destroyed by the ancient lava flow.

Vitello image courtesy of Bruce Rohrlach

After all the excitement of that Blue Supermoon at the end of August, Friday 29th September sees the next Full Moon.  I mentioned the autumn equinox last week and this Full Moon is known as the 2023  "Harvest Moon" because it is the closest one to that September equinox.

There are several opportunities to spot the International Space Station in the early evening next week, the best chances being Monday 25th at 7.49pm and Wednesday 27th at 7.50pm.  In both cases, the ISS will appear towards the west and spend about six minutes passing almost directly overhead before disappearing to the east.

If you are up early, any morning next week and look towards the east, Venus will have risen above the horizon from about 4am.  It is currently shining very brightly at a magnitude of -4.5

By around 5.30am, Venus will have climbed higher in the sky and to the left of it, Mercury will be popping its head up above the horizon.  Towards the end of the coming week, Mercury reaches its greatest western elongation from the Sun (when it appears to be furthest from it).  Mercury won't be quite as bright as Venus as it currently has a magnitude of -0.3

Remember that the magnitude scale is back to front, so the more negative the number, then the brighter an object is.  To put that into context, our own Sun has a magnitude of around -26 so that is why you never attempt to look at it through binoculars or a telescope!  For this reason, I would not be tempted to use your telescope to get a better view of Venus and Mercury next week as the Sun will be rising in the same spot a little later and you don't want to accidentally catch a glimpse of it!

While we are on the subject, on the morning of Saturday 23rd, the centre of the Sun crosses the celestial equator as it moves from the northern celestial hemisphere to the southern celestial hemisphere.  What on Earth does that mean?  Well it marks the autumn equinox or the point on the autumn calendar when we have equal periods of night and day.  In other words, we are halfway towards the shortest day in December - hard to believe after all that hot weather last week!

The coming week will appeal more to the early risers amongst us rather than staying up into the late evening.

Go outside anytime from 4am on Monday 11th and a 12%-lit Waning Crescent Moon will have risen above the horizon towards the east.  Below and to the right of it will be Venus who will also appear as a crescent shape if viewed in a telescope.

Aim your telescope to a point just below the Moon, running in a line towards Venus and you should be able to find the Beehive open cluster of stars, also known as M44 in the Messier Catalogue.

The cluster has around 1000 stars and is one of the closest clusters to us, about 610 light years away.  It has a magnitude of -3.7 so from a dark location you should even be able to see it with the naked eye, although without a telescope it will resemble a fuzzy blob.

Much easier to spot is the bright star Procyon to the right of the Moon and Venus.  Procyon is the 8th brightest star in the night sky with a magnitude of +0.34 and it is actually a binary system, but you will only be able to see the main star.  Its companion faint white dwarf star will be invisible.

If you really fancy a challenge, a 1%-lit Crescent Moon rises above the eastern horizon about an hour before sunrise on the morning of Thursday 14th.  To the right of it will be a magnitude +1.8 Mercury.

Please remember not to risk using a telescope to obtain a better view as the Sun will be rising shortly afterwards in the same place!

If you venture outside around 11pm on Monday 4th, a 70%-lit Waning Gibbous Moon will have risen above the horizon towards the east with a magnitude -2.5 planet Jupiter just to the right of it.

When you look through your telescope's eyepiece, the four moons will be the opposite way around to have I have listed them - because of the way their optics are designed, astronomical instruments always produce an inverted or upside-down view!

If you use binoculars, which are designed for looking at things on the Earth, then the image will be the correct way round.  Binoculars incorporate an extra prism to correct the image, but the process loses a little bit of light.  This is done because if you're looking at a ship in the distance, it's nice to have the sea at the bottom and the sky at the top!  Astronomers don't care if their target is the other way up as it's far more important for them to collect as much light as possible!

There are a couple of great opportunities to spot the International Space Station at the beginning of next week.  On Monday 4th it appears over the horizon to the west at 5.23am and reaches an altitude of 77 degrees as it spends 6 minutes heading towards the east.  On Tuesday 5th, it will appear in the west at 4.37am and pass directly overhead.

Screenshots courtesy of Stellarium

Copyright Adrian Dening and Radio Ninesprings 2023