Jupiter at its finest but poor weather does not help
December is when Jupiter comes it closest and should be the best time for observing it, it reaches opposition on December 3rd, with an apparent diameter of 48.5 arc seconds. For those not familiar with these units that is very big indeed for a planet observed from earth, in fact almost as large as it gets. Saturn by comparison is typically much less than half that diameter and Mars for example is generally around just over a quarter of that size. The moon is much larger – in fact around 35 times larger. This means that for planets very high magnification is the order of the day and that requires a quality telescope that is very carefully collimated.
The picture below was taken by the author at the beginning of December and shows the moon Ganymeade starting to cross in front of the planet, casting its shadow. Some shady detail is just visible on Ganymeade. This was taken from Abergavenny using a webcam and an 8″ reflecting telescope.
There are more meteor showers this month, specifically the Geminids. This should be a very good show this year and lasts from the 12th to the 14th of the month. What’s more the moon is out of the way. These meteors are a little different as most meteor shower are the remnants of comet’s tails. The Geminids are believed to be the remains of an asteroid type object called 3200 Phaeton.
As it turns out the weather in December was pretty dreadful for observing anything with a lot of cloud and rain. There was some stable seeing – that is to say the air was steady but this was let down but poor transparency due to mist and fog. Let’s hope for better weather in January. Hope everyone had a great Christmas and a happy New Year to all.
It’s firework season in November
Who needs gunpowder treason and plot? November has its own fireworks with meteor showers for much of the month. The first shower peaks coincidentally on the 5th of November. These meteors appear to radiate from Taurus – which is hard to miss this year with Jupiter slap bang in the middle. This is only an effect of perspective and the meteors can be anywhere in the sky they just look as though they radiate from Taurus. Look after midnight for the best chance of seeing them. The moon is below the horizon by the 5th. Taurids have a reputation for being slow moving with some big fireballs. Not content with just one showing the Taurids will return on the 12th for an encore performance. Again they will seem to emanate from Taurus.
On the Weekend of the 17th and 18th of November we have the Leonids putting on their show. The Leonids are famous for having some truly wonderful meteor storms in the past, 1833 was probably the best ever recorded and depicted in this 1889 print. Unfortunately such a shower is not predicted this year but still worth looking out for. They are fast meteors and can be seen from the 15th to the 20th of the month. They appear to emanate from the head of Leo. Although this radiant point will be hard to notice as Leo does not rise until around midnight in the East the meteors should certainly be in evidence. Again there is no moon.
Jupiter is now a magnificent sight, high in the South reaching almost 60 degrees at around 01:20 UT in the middle of the month. It is still in Taurus with the magnificent constellation of Orion beneath. Try looking for the Great Red Spot and his little friend Oval BA. The transit times for November are given below:
1: 21:20; 2: 17:11; 3: 22:58; 4: 18:49; 6: 20:27; 8: 22:05; 9: 17:56; 10: 23:43; 11: 19:34; 13: 21:12; 14: 17:04; 15: 22:51; 16:18:42; 18: 20:20; 19:16:11; 20: 21:58; 21:17:49; 22: 23:36; 23: 19:27; 24: 5:23; 25: 1:14, 21:06; 26: 7:01, 16:57; 27: 2:53, 22:44; 28: 18:35; 29: 4:31; 30: 0:22, 20:13
At the very end of the month Mercury puts in an appearance just before sunrise in the South East, but you will need a good horizon. If you decide to look for it be very careful indeed as it can be perilously close to the sun. If you accidentally point any optical instrument at the sun while you are observing you will without doubt damage your eyesight permanently.
November brings one of my favourite objects to prime position. Although circumpolar – meaning it never sets the double cluster in Perseus is truly beautiful. At this time of year it is overhead so a wonderful object to observe or photograph, as light pollution will be minimal. I say “object” in fact it is two clusters for the price of one, they lie in line of sight and look related but in fact are 800 light years apart and one is almost twice as old as the other. They are still quite young, the oldest is just under 6 million years old, still juvenile in stellar terms, the Pleiades is probably 30x older. You can find them as a faint milky patch visible to the unaided eye between Cassiopeia and Perseus. They look beautiful in binoculars but the higher the magnification the more detail you see. With a time exposed photograph one really begins to appreciate the number of stars involved. The picture below was taken from my observatory on the 13th September 2012, when it was a bit lower in the sky.
Return of the King in October skies
October can be a variable month from an observers point of view. The cool misty evening can be excellent for planetary observing but is usually difficult for deep sky observers. So far this year the weather has been pretty poor whatever the subject and when it has been clear the jet stream has been around. This leads to the shimmering effect that makes stars twinkle, more correctly known as scintillation it makes life very difficult when trying to capture images at high magnifications.
In the middle of October Jupiter rises at around 8 pm in Taurus, but is not really high enough to observe well until around midnight. The picture below was taken on the 13th October 2012 at about 6:40 am when there was a bit of clear seeing.
It clearly shows the Great Spot to the lower right with the smaller “junior” red spot, or Oval BA to give it its more formal name. Notice the long tail of turbulence following them around the planet in the South Equatorial belt. The Great Red Spot has been followed by observers for at least 300 years, whereas the Oval BA only formed in 2000 when three smaller white spots merged. These features are huge anticyclones in the planet’s atmosphere.
The picture below is an animation comprised of around 4 hours of frames and showing the rotation of the planet. This was taken on the 22nd September. Click the image to see the animation. Look carefully to the lower left and you can see Ganymede tucking in behind the great planet. This sequence also shows quite nicely how seeing conditions can change and there is a clear improvement near the end of the sequence which was just before dawn; after the air and ground have had a chance to cool off and the convection currents stop at this time – not advise if you have work the next day though!
Jupiter is a fascinating planet to observe as it constantly changes the picture below shows how it looked last year compared to this year. The difference in the equatorial belts is obvious. The bands come and go as high level clouds of gases such as ammonia cover up the darker bands before clearing away again over a period of months.
Jupiter really requires quite high magnifications to see at it best, although even binoculars will easily show the 4 Galilean moons, Ganymede, Callisto, Europa and Io. They will also show the bands. An 80mm ( 3″ ) refractor is capable of showing the Great Red spot but “Junior” is much harder to resolve and at the moment and looks just like part of the GRS. These pictures were taken with a 200mm (8″) Maksutov catadioptric telescope. Even a 150 mm (6″) Newtonian will show some detail in the clouds
Also worth looking out for is Venus which this month appears as an intensely bright morning star, just before sunrise in the South East.
Return of the Pleiades in the September skies
I always think that first sign that summer has come to an end is when I see the Pleiades rising in the north east soon after the sun has set and by the middle of the month that is happening less than an hour after it gets dark. This picture was taken from Abergavenny by the author on the 13 September. Notice the nebulosity surrounding the stars, this material glows by reflecting the light of the bright blue young stars. This picture was a 1 hour exposure using a very modest 5 inch reflecting telescope, worth around £100 when new.
By 11 pm, Taurus the bull rears its head over the horizon, followed closely by Jupiter. But for much of the month Jupiter is too low to observe well before midnight. There are a couple of other gas giants to look out for though. Neptune is high in Aquarius. It can be seen even in fairly small scopes but its apparent diameter of about 2.4 “ means you will probably need a 6” reflector or equivalent to make out the disk, it has a magnitude of 7.8 so is not visible to the unaided eye. Uranus is a much easier proposition. Presently in Pisces and with a magnitude of 5.73 it can at least in theory be seen with the unaided eye. At 3.7” diameter the disk is relatively easy to see, even in a small telescope. It has a greenish-blue colour from its methane atmosphere but you will not seen any details on it featureless face.
September and October evenings have a habit of been damp and misty with heavy dews. This can be a nuisance with dripping optical surfaces and poor transparency, but it can give very steady seeing for planetary observers.
Deep sky observers will have a hard time until around the 12th of the month as the new moon is on the 31st August and rises prominently in the early evening for the first week or so. After the 12th it is tucked away and all we can do is hope for some clear skies. This is a great time for looking with binoculars especially to the East. The Andromeda Galaxy M31 is a classic, nestling between Pegasus and Cassiopeia it is an easy naked eye object on a good dark night and looks better in binoculars than it does through a telescope. My other favourite the double cluster is also high in the sky between Perseus and Cassiopeia. Another naked eye object it looks great in binoculars but even better with a telescope and high power shows more and more detail.
Nature’s fireworks in the August night sky
Milky way around Cygnus from the Brecon Beacons visitor centre, 10th May 2012 showing the summer triangle.
Vega is the bright star at the top just right of centre.
Altair is to the lower right and Deneb centre.
The summer triangle, milky way and the double cluster in Perseus
As the evenings draw in with autumn just around the corner, it is a wonderful time to sit back, while it is still warm enough, and watch the stars emerge one by one as night falls. By the end of August the sun sets just after 7pm and by 8:30 it is quite dark. Not being near to a city Abergavenny is blessed with dark skies and is also close the Brecon Beacons National Park; that enjoys some of the darkest skies in the UK.
The August night sky is particularly beautiful with the Milky Way being very prominent. This hazy band of light running virtually overhead, from the northeast to the southwest horizon, is the galaxy that is home to our sun and all the stars that you can see. At this time of year, where the milky way meets the horizon in the south east is the constellation of Sagittarius, looks a bit like a teapot. Close to where its spout appears to be is the very centre of our galaxy and the home of the super-massive black hole located there.
Looking overhead there is a prominent bright blueish white star, this is Vega in the constellation of Lyra. Lyra looks like a small diamond shape and is very recognisable. Just to the east of Vega (left) is another prominent star that is part of a large cross-shaped constellation, called Deneb, this is the tail of Cygnus, the swan. Cygnus is flying along the milky way and it is a delight to scan this part of the sky with a pair binoculars to view some of the myriad of stars comprising our galaxy. On a very dark night a central dark patch can be seen running through Cygnus. In fact it is dust within our own galaxy that is obscuring the stars in this area. The long neck of Cygnus points along the milky way to the south east and the head is marked by the star called Albireo. This star is worth taking a closer look at even with a small telescope as it is one of the most beautiful double stars in the sky, with an orange star and small blue partner. Below Vega and Deneb is another bright star, Altair. This is in the constellation of Aquila, the eagle. These stars make up the so called “summer triangle” which is useful in helping you to orientate.
Another favourite constellation for orientation is Cassiopeia. This is the “W” shaped constellation that can be found by following the milky way that runs to the north west from Cygnus. Cassiopeia is also a lovely sight in binoculars as it contains many open star clusters that reside in the plane of the galaxy. Looking with binoculars just below the left “V” of the “W” shape reveals one of the treasures of this part of the sky, the Perseus double cluster. These are two open clusters that are so close they can be seen in the same field of view at low magnification. On a dark night it is not difficult to see the double cluster with the naked eye, it appears as a small hazy patch.
On the evening of August 11th is a special treat, the Perseid meteor shower. These fast moving meteors or shooting stars come every year about this time. They are made from bits of dust from the tail of the comet Swift-Tuttle after it passed through this part of the earth’s orbit over a 1000 years ago. Lie back on the ground or a deck chair and simply look up. The meteors can appear anywhere in the sky. At the shower’s peak, sometime after midnight, you may see up to one meteor per minute. They are called the Perseid meteors because they appear to radiate from the constellation of Perseus. In fact to be more precise they radiate from close to the double cluster described above. The meteors typically start a day or two before the 11th and go on for a couple of days after.