Friday, 24 January 2014

Capturing a Supernova

They don't come along very often. Supernova SN 2014J was discovered by astronomer Steve Fossey, of University College London and four undergraduate students on 21st January. It is a  Type Ia supernova, the closest Type Ia supernova in the last 40 years. Type 1a supernova's are very useful as they produce a consistent peak of luminosity due to the uniform mass of white dwarfs that explode via the accretion mechanism. The value is very stable and allows these explosions to be used as standard candles to measure the distance to their host galaxies. This is because the visual magnitude of the supernova depends primarily on the distance.

Unfortunately, the supernova may put on a great show, but the Scottish weather doesn't always play ball. I set up my scope (an 8" reflector) and camera last night in my garden and took some images. Between the clouds and the threatening rain I only got about 10 minutes of useful imaging before I had to give up. However, the supernova is really obvious once you find the target. I saw it straight away. The image above shows M81 and M82. M82 is the lower cigar shaped Galaxy and in the mid-upper left you can see Supernova 2014 J.

If we zoom in on M82, the supernova is quite clear as an orange spot to the upper left of the Galaxy.

Checks by astronomers have found that the supernova was visible on images taken as early as January 15th. Indications were that the supernova was discovered approximately 14 days before maximum light, so it is expected to get brighter over the following fortnight, probably bright enough to be visible with binoculars throughout the Northern Hemisphere within a couple of days. It should reach maximum brightness of around magnitude 8.5 or so with the next two weeks.

Tuesday, 14 January 2014

Jupiter and the Moon

If you are lucky enough to have clear skies tonight, and don't count on it in Scotland, you may be able to see Jupiter pass within six degrees, and a little to the left, of the Moon. Now, to be clear, this is not technically NOT a conjunction, but they will look close. Technically conjunctions are defined as occuring when two astronomical objects have either the same right ascension or the same ecliptical longitude, normally when observed from the Earth. This can happen between planets, planets and the Moon, sometimes (very rarely) more than two objects may be involved. Often they just appear close, sometimes much closer, and sometimes very close. Last year was better for the Moon and Jupiter. The image below shows a Stellarium screenshot of how it will appear tonight from Scotland.

Last year I was lucky enough to get a decent photo of Jupiter and the Moon when they appeared slightly closer in the sky . The photo below is a composite shot, but shows their actual positions.

I took three separate images, as it is impossible to capture all the detail in one exposure. I took one photo of the Moon, one of Jupiter and one of Jupiter's moons, all using a Fuji high zoom bridge camera. I then built the image in Gimp. If you have clear skies, head out for a look. Better still, take a photo!

Thursday, 2 January 2014


I like to take photographs of individual stars. Capella is a favourite of mine, it is the brightest object in the constellation of Auriga, it's the sixth brightest star in the night sky and the third brightest star in the northern celestial hemisphere, after Arcturus and Vega. In Winter its high in the sky and an easy target to observe.

This photo is a single 30 second exposure through my 8 inch scope and using a Nikon DSLR. After I posted this photo on Flickr, in the Sky at Night group, I got an email from a researcher at the BBC. He told me he liked my photo a lot and it had been shortlisted for this year's BBC Stargazing Live Calendar. To say I was pleased was an understatement. Unfortunately, in the end it just didn't make the final selection, which was a shame, but I was still very pleased it had been shortlisted. Maybe next time!

An interesting fact about Capella is that it is actually a star system of four stars in two binary pairs. The first pair consists of two bright, large type-G giant stars, both with a radius around 10 times that of the Sun's, in close orbit around each other. The second pair, around 10,000 astronomical units from the first, consists of two faint, small and relatively cool red dwarfs. The Capella system is relatively close, at only 42 light years from Earth.

Wednesday, 1 January 2014

New Year Discovery

On the first day of a new century, 1 January 1801, the astronomer Giuseppe Piazzi, working at Palermo observatory in Sicily discovered what he first thought was a tail-less comet. After a series of observations, interrupted by illness; and once its orbit was calculated, he realised he had found a 'new planet'. It was named Ceres after the Roman goddess of agriculture and the patron goddess of Sicily. It fitted nicely within Bodes law. between Mars and Jupiter, that strange algebraic “formula” law which seemed to predict the orbital distances of the planets and had just roughly predicted the semi-major axis of Uranus's orbit. Later observations however showed it to be rather small for a Planet and then more and more 'objects' of a similar nature were found reducing Ceres to what was thought to be the largest asteroid. Now though Ceres has had it's nature changed again, and it is now the second largest of what are called 'Dwarf Planets', Pluto being the largest.

Ceres can be tricky to find. It is often just on the verge of human eyesight, even from a dark site, but binoculars and small telescopes show it as a faint star like object. At the moment it can be found using binoculars in the constellation of Virgo, in the early hours of the morning. Ceres is due to be visited by the NASA spacecraft Dawn in 2015, the same year as New Horizons will fly-by Pluto. We should therefore get two good looks at two dwarf planets. Both make interesting targets for a number of reasons but should provide clues as to the origin of the solar system. At the moment, if you get a chance, see if you can find Ceres. It is an interesting spot and many astronomers spend a lifetime without ever giving it notice. The other dwarf planets are a much harder proposition to see.

Tuesday, 24 December 2013

The Science of Santa

Astronomy may be my first love, but I am a Physicist by profession, so, lets do some Physics for Christmas:

Now, with Christmas fast approaching, and children all over the world eagerly awaiting Santa's arrival, just how does the man in red do it? Firstly, this exercise has been repeated before and I make no apologies for redoing this subject. Now, onto the science. It's estimated there are 2 billion children in the world under 18 years of age. Santa is primarily a figure in the Christian religion so that leaves around 380 million kids, around 15% of the total, according to the Population reference Bureau. At an average 3 ½ kids per household that's about 92 million homes to visit. We will also assume no children are on the naughty list, a big assumption in my experience.

Luckily, thanks to time-zones and the rotation of the Earth, Santa has 31 hours to do his rounds. If he follows the night and goes East to West that works out at about 825 houses to visit per second. If we assume all the houses are evenly distributed, that gives Santa around one millisecond (one thousandth of a second) for each house. We can now estimate his total journey on Christmas night to be around 75 million miles, phew! To cover that distance Santa, his sleigh and the poor old reindeer will have to travel at around Mach 3000, or about 650 miles per second.

Now, the sleigh has to be filled with presents. Assuming each child gets a modest present, weighing about a kilo, that give a total weight of just under 400,000 metric tons. In reality it's estimated that reindeer can each pull a load of around 150 kilos, so he would actually need just under 3 million reindeer. Now, all that weight travelling at that incredible speed would create a massive amount of air resistance. One estimate is that the leading pair of reindeer would be absorbing around 30x10^18 Joules of energy per second and be subject to forces of around 18,000 g. It's no wonder the big guy and his flock need the rest of the year off!

Wednesday, 6 November 2013

Unseasonal Weather

One thing you can normally rely on in November in Scotland, is that the weather will be rubbish. However, we recently have been in for a treat, four out of the last five nights have been clear. Not one to pass on such an opportunity, I have been out with my scope every clear night and thought I would share a few photos. First on the list is M57, The Ring nebula.

Located in the constellation of Lyra, the ring nebula is a planetary nebula. Such objects are formed when a shell of ionized gas is expelled into the surrounding interstellar medium by a red giant star, which was passing through the last stage in its evolution before becoming a white dwarf.

Next comes the double start Albireo, quite possibly the most beautiful double star in the night sky.

Located in Cygnus, it appears to the naked eye to be a single star of magnitude 3 but through a telescope, even low magnification views resolve it into a double star. The brighter yellow star makes a striking colour contrast with its fainter blue companion star. It's a lovely thing to look at.

Finally, the photo below shows the star Mirach, the second brightest star in the northern constellation of Andromeda. Even through a telescope it appears as just a bright star, but it holds a secret. Look closely and you will see the faint fuzzy outline of NGC404, a dwarf eliptical galaxy, known as Mirach's ghost. It's 10 million light years away but just happens to lie in the line of sight of Mirach

All of the above images were taken from my garden through an 8" reflector and all of them are single 30 second exposures with a Nikon DSLR. The recent weather may be unseasonable, but I hope it continues.

Monday, 28 October 2013

Britain's Lost Horizon's - Prospero X-3

If you know exactly where to look, you could theoretically see it. Weighing in a 66 kilos and orbiting the Earth every 104 minutes since it's launch on this day in 1971 is Prospero X-3, the British space program greatest achievement. The only satellite entirely designed and built in Britain and launched by a British designed and built rocket, the Black Arrow, it should continue to orbit the Earth for at least the next 50 years, a shining example of the success and failure of the British space program. To this day, it reminds us all that Britain has the dubious honour of being the only country in the world to successfully developed and then abandoned a satellite launching capability. All other countries that have developed such a capability have either retained it through their own space program, or in conjunction with others.

Back in the 1950's and 60's the future looked rosy. Britain was going places, and space was one such place. Rocketry in the UK was developing along military lines at first with the desire for an independent ballistic missile capability. Firstly, with Blue Streak and then Black Knight, powerful liquid fuelled rockets were developed that were marvels of technology at the time, way ahead of the competition. Then some people saw the opportunity to get into the space business and use that technology to launch satellites, and so Britain's space program began. But in 1971, just as the government and the men from the ministry stepped in to cancel development of these rockets on the grounds of cost, Britain's space program was ready to launch. Fortunately for all those involved, Prospero and it's rocket had arrived at the launch site in Australia just weeks ahead of the cancellation, and it was decided that the launch might as well go ahead, as it wouldn’t cost any more money. Early in the morning of the 28th October that year, the Black Arrow rocket thundered into orbit, pushing Prospero up to a maximum height of over 800 miles. Up until only a few years ago the little satellite was still transmitting it signal back home, in the vain hope that someone was actually still listening.

The world today of course is a very different place. Even the US has given up the ability to put it's own astronauts in space for a while with the cancellation of the space shuttle program. Commercial launching seems to be the future. But if you ever find yourself staring up at the sky on a dark night, if you knew where to look, you might just be able to glance a view of Prospero as it's orbits above us in it's fairly stable long term orbit. If you do, can I suggest you raise a toast to those early British rocket men, with their tweed suits, slide rules, pipes and can-do attitudes. They truly were ahead of their time