On Monday 26th it's the turn of Jupiter to be at opposition, when it will be at its brightest with an apparent magnitude of -2.8.  If you go outside just after dark, Jupiter will have risen above the horizon a little south of due east.  Looking further south, Saturn will be there shining at a magnitude of around +0.5 which is very confusing as Jupiter will be the brighter of the two!  When I did maths at school +0.5 was bigger than -2.8 so what's going on?

The apparent magnitude scale works back to front and the brighter an object is, then the more negative its magnitude figure will be.  The brightest star in the night sky, Sirius, has a magnitude of -1.4 and a Full Moon is around -12.9 or in other words, much brighter.  From a dark sky location with the naked eye, it is possible to see objects down to a magnitude of around +6.  Binoculars will enable you to see slightly fainter objects down to a magnitude of +8.  Any dimmer than that is "telescope territory".  To put that into context, our own Sun has an apparent magnitude of -26 which is why you never look at it through a telescope!

I'm often asked how much my telescopes magnify things, but that is not really the correct question!  The question should be regarding how much light the telescope collects - the larger the aperture (or the bigger the hole in the front) then the more light the telescope can collect.  Once as much light as possible has been collected, then the magnification is a function of the eyepiece.

To learn more about this, why not come along to one of my Stars Over Somerset lectures at Ham Hill on 21st October and 18th November.

The dates for your diary are Friday 21st October and Friday 18th November from 7 to 9pm.

On both evenings, there will be a talk on general astronomy and observing tips, lasting about an hour and then after some refreshments, we will be heading outside to conduct our own little adventure into space.  The Moon will not be visible, so that gives us an un-polluted view of the Andromeda Galaxy 2.5 million light years away and the planets Jupiter and Saturn.  Towards the end of the viewing session, Mars and the Pleiades cluster of stars will be appearing over the horizon, followed by the Great Orion Nebula.

Our “special guest” for the evening will be a large piece of the Campo del Cielo meteorite that crashed into Argentina over 4000 years ago!

The events are suitable for all the family and the cost is £7 per adult, with a reduced rate of £3.50 for children under 18 years of age.  Booking is essential as places are limited.  Bookings can be made online via the  www.visitsouthsomerset.com  website under the Ham Hill tab.

The actual use of the telescopes will be dependent on there being clear skies each evening, but don't worry as I have a "Plan B" if the weather isn't co-operating!

It's a week for observing the four gas giant planets - Jupiter, Saturn, Uranus and Neptune - that live in the outer part of our Solar System.  All the observations can be made just after dark, so no late nights are required!

On the evening of Wednesday 14th, a rare event known as a Lunar occultation occurs where the Moon appears to pass in front of the planet Uranus, blocking the gas giant from view for around fifty minutes.

Look to the east at 10pm and you will find a 77%-lit waning Gibbous Moon with Uranus slightly to the left of it.  The gas giant will have a magnitude of around +5.7 so you will need binoculars or a small telescope.  As the bright leading edge of the Moon, or to use the correct technical term, leading limb approaches Uranus, it will take about 8 seconds for the gas giant to disappear behind it.  Fifty minutes later, Uranus will appear again from behind the Moon's dark following limb to the right.

On Friday 16th, Neptune is at opposition, so it will be at its brightest around a magnitude of +7.8  If you go outside around 10pm and look towards the south east, Jupiter will be a little to the left and Saturn will be to the right.  Above Jupiter is the constellation of Pisces and at the right hand end of Pisces is the shape or "asterism" known as the Circlet because it resembles a circle of stars.  Neptune is below the Circlet.  Again, you will need a telescope because of the planet's magnitude.

If you fancy a bit of a challenge and don't mind an early start around 4.30am, there is an opportunity on Thursday 8th to spot minor planet 3 Juno that lives in the Asteroid Belt and the gas giant Neptune.  3 Juno will be at opposition, or in other words, the brightest it gets at a magnitude of +7.8.  Neptune will have a similar magnitude so you will need to dig out that telescope to see them.  A Gibbous Moon will have already set in the west, so no light pollution to spoil your view.

On Saturday 10th, a Full Moon rises above the horizon to the east just as it gets dark.  This Full Moon is the closest one to the Autumn Equinox when we have equal periods of light and dark, so is called a Harvest Moon.

The Autumn Equinox occurs on September 23rd and on that day, the Earth's tilt of 23.5 degrees is side-ways on to the Sun.  The Sun also appears to rise due east that morning and sets due west in the evening.  If you were on the Equator, the Sun would be directly overhead at midday.

While looking at the Moon, you could also take a look at Jupiter to the left of it and Saturn to the right, but the bright Sunlight reflecting off the lunar surface will spoil the contrast somewhat.

If you go outside a little after dark, say from 10pm, the Moon will have already dropped below the horizon to the west and so will be producing zero light pollution - a favourite time for astronomers who want to go hunting deep sky objects - those faint fuzzy blobs.

I like to classify deep sky objects into three different types - clusters of stars (either globular or open clusters), nebulas (or collections of gasses) and finally galaxies.  The clusters and nebulas are relatively close to us, within our own Milky Way galaxy, where the neighbouring galaxies are millions of light years away, far outside the Milky Way.  Of course if you could get up close to one of those galaxies, you would see that it contains billions of stars along with clusters and nebulas of its own.

If you look towards the east south east, find the constellation of Pegasus.  To the left of Pegasus is the next closest galaxy to us, the spiral shaped Andromeda Galaxy M31.  It is quite an easy target to find with your telescope despite being a whopping two and a half million light years away from us!  When you look at it, you are seeing the galaxy how it was 2.5 million years ago as the light has taken that long to reach us!  From a very dark location it is even possible to make it out with the naked eye.

Alternatively, to the right of Pegasus is a 12 billion year old globular star cluster, catalogued by Charles Messier while he was comet-hunting and given the designator M15.  A small telescope will reveal a definite glow or fuzzy blob; a larger telescope will show a bright core with a halo of surrounding stars.  It is only 35,000 light years away from us- in other words, well within our Milky Way.

A couple of weeks ago I mentioned that Saturn was at opposition which meant that its rings would be at their brightest.  Next week, on Tuesday 23rd, it's the turn of minor planet 4 Vesta to reach opposition and it should have a magnitude of around +6.0.  This makes it an easy target for binoculars or a small telescope or even the naked eye from a dark sky location.

4 Vesta is the second largest lump of rock in the Asteroid Belt, only beaten by the dwarf planet Ceres.  The "4" signifies that it was the 4th minor planet discovered, back in 1807.  It is the brightest asteroid visible from Earth and has a diameter of only 525Km or a little over 300 miles.  Vesta's name comes from Roman mythology - the goddess of home and hearth.

So where will it be and how do you find it?  If you are outside from 10pm local time, our old friend Saturn will be towards the south east and Jupiter will have just risen above the horizon to the east.  If you are in a nice dark location, you might be able to make out the faint cloud of the Milky Way stretching from the southern horizon up towards the bright star Altair.

Anyway.....back to 4 Vesta.....the minor planet is located a little down and to the left of Saturn.  I have included a star chart below to help you locate it - the trick is to use the patterns of stars on the chart to judge its approximate position.

Finally, some advance notice that I have organised a couple of astronomy lectures and star parties at Ham Hill Country Park for the evenings of Friday 21st October and Friday 18th November.  Further details will be available on the Visit South Somerset website and here when the event booking system is set-up.

Firstly a reminder that it is still a great time to observe the rings of Saturn at their brightest because the planet is close to opposition with the Sun.  If you go outside around 10pm local time, Saturn will be quite low towards the south east, with Jupiter rising above the horizon to the east.  If you stay up later, the pair will gradually climb a bit higher in the sky and this gives better viewing because the Sunlight reflecting from them will then be travelling through our atmosphere at a sharper angle which results in less disturbance.

The bright star Altair will be above Saturn.  It's important to realise that stars don't twinkle and the light radiating from them is a relatively constant source.  But then if you look at Altair, I bet you will notice it twinkling-away like a good 'un.  That's only because the light is being twisted by our atmosphere.  The higher an object is in the night sky then the less atmosphere its light has to travel through and so the effects are lessened.

If you stay up until around 1am, everything will appear to have rotated around and Saturn will be more towards the south, with Jupiter towards the south east.  Of course they haven't really moved - it's us that has rotated as the Earth spins on its axis!  The Moon will have risen above the horizon close to Jupiter and Mars will have popped up a little north of due east.

Oceanus Procellarum is situated on the west side of the Moon's face and I have included some diagrams below, courtesy of Wikipedia, to help find the swirl.

The origin of Lunar Swirls is not fully understood, but believed to be associated with magnetic activity.  Several robotic probes have landed in the Ocean of Storms, including Surveyor 3 in 1967.  The Apollo 12 astronauts famously touched-down only 165m away from Surveyor 3 a couple of years later and retrieved several items from it to return to the Earth.

It will be necessary to use a telescope for a good view of the Reiner Gamma swirl and at the same time, you could take a look at Saturn's rings.  Next week, Saturn is approaching a point in its orbit called "opposition" when the Earth is directly between the planet and the Sun.  This gives the best opportunity to observe Saturn's rings as they will be at their brightest.

Something a bit different this time.  I often give a dire warning about the dangers of attempting to look at the Sun through binoculars or a telescope, but many astronomers do make successful observations of our neighbouring star in complete safety.  How do they manage it?

The light you see originating from the Sun is classed as "white light" which is a mixture of all the different wavelengths or colours.  A telescope for this is either fitted with a special filter in front that stops virtually all the light from entering the tube in the first place or a device called a Herschel wedge that bins most of the light collected by the telescope before it can reach the eyepiece.  White light images are great for showing Sunspots - areas on the Sun's surface where the temperature is considerably lower than the rest of it..........4000 degrees Celsius as opposed to 5500 degrees!

A far more specialised type of telescope focuses on just the red wavelength of light given off by Hydrogen burning and these Hydrogen Alpha telescopes show stunning prominences or flares flying off the Sun's surface in real time.  White light images are just too bright to show these prominences as the amount of light washes out the detail.

If you'd like to witness all this for yourself, I am running some "Daytime Astronomy" sessions with my Solar telescopes at Braeside House in Devizes during their Family Day on Saturday August 6th.  Why not come along - entry is free and there are all sorts of crafts, activities and even a hog roast!  To find the details, please visit  Braeside Education Centre

Sun images courtesy of Lunt Telescopes