Adrian Dening's
Stars Over Somerset

 

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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 22nd to Sunday 28th August 2022
 

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.

 

 

Monday 15th to Sunday 21st August 2022
 

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.

 
 
Go outside at the same time on subsequent evenings during the week and the planets will appear to be in a similar position, but not the Moon as it is following a completely different path - orbiting around us.  At 1am on Saturday 20th, the Moon will appear to be in the east, forming an isosceles triangle with Mars and the Pleiades cluster of stars.
 

 

 

Monday 8th to Sunday 14th August 2022
 
On Friday 12th we have a Full Moon.  Many of the Lunar visual effects I have mentioned in the past require Sunlight to be falling on the surface at an oblique angle, but some are better seen around the time of a Full Moon and these are called Albedo Features.  These large features are so named because they have a high contrast with the area surrounding them.  One such example is what looks like a bright swirl called Reiner Gamma located in Oceanus Procellarum or the Ocean of Storms.
 
If you go outside around 11pm on 12th, the Moon will be located towards the south east, with Saturn a little to the right of it and Jupiter on the left looking more to the 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.

 
 
Saturn image courtesy of NASA

 

 

Monday 1st to Sunday 7th August 2022
 

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

 

 

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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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