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!

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.

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

Enigmatic Europa

Discovered in 1610 by Galileo, Europa is the smallest of the four 'Galilean Moons' of Jupiter. Through a small telescope its easy to spot as the second one out from the planet. It is named after a Phoenician noblewoman in Greek mythology, Europa, who was courted by Zeus, the father of Gods, and became the queen of Crete. Europa is slightly smaller than our own moon and orbits Jupiter in just over three and-a-half days. Its density suggests that it is similar in composition to the terrestrial planets, such as Earth and Mars, and is mainly composed of silicate rock. It has long been thought that Europa has an outer layer of water around 60 miles thick, some of this frozen as an ice upper crust, some as a liquid ocean underneath that ice. Europa has also featured high in science fiction, most notably in Arthur C Clarke's '2001' where it was home to a primitive life form, seeded there by aliens and set into evolutionary overdrive when Jupiter is transformed into the Star Lucifer.

It was long thought that it would be difficult for any water to travel up though Europa's thick icy crust, but researchers at the The University of Texas found the best evidence yet for water just beneath the surface of Europa. An analysis of the surface suggests that plumes of warmer water well up beneath the icy shell, melting and fracturing the outer layers. They also suggest that small lakes exist just a couple of miles below the crust.

The researchers studied the surface of Europa trying to work out what formed its scarred and fractured surface. They suggest say up-welling of warmer water causes melting of surface ice, forming cracks. Freezing water then flows in the cracks and so you get existing ice cemented in with new ice. The underside then freezes again, which causes more uplifting. These shallow lakes mean that surface waters are probably vigorously mixing with deeper water. It is also possible that icy eddies could transfer nutrients between the surface water and the deeper ocean below. All this is another boost to those who think Europa is a place which may well harbor life.

Finding Comet Ison

Comet ISON is becoming more and more visible to the amateur astronomer this month. From the UK though it means an early start as it doesn't rise until around 0230 (this weekend). On the plus side however, given clear skies it is easy to locate, if not actually spot, as we have a couple of celestial pointers. Around 0400 it should be high enough to be out of the 'murk'. Look for the constellation of Leo, The Lion, and find Regulus, the bright reddish star to the bottom right. Mars should be visible below and to the left, shining at around magnitude 1.7. Follow a line down to the left, about a third of the distance again between Regulus and Mars, and ISON should be there, Visible in a scope of around 6" diameter. If you do astrophotography the best way to image it would be through a shortish image at a high ISO. say 30 seconds at ISO 1600. Remember though, if you scope is tracking normally, the stars will come out sharp, but ISON may be blurred. That is because the comet is itself moving against the background of stars. The image above shows where ISON can be found in the early hours of Monday 21st October, from the North of the UK.

Penumbral Lunar Eclipse 18-19 October 2013

Tonight there is a Penumbral Lunar Eclipse. This type of eclipse occurs when the Moon passes through the Earth’s penumbra, that is the outer shadow (seen above). The penumbra causes a subtle darkening of the Moon's surface as viewed here on Earth. At no time during this eclipse does the Moon pass through the inner shadow, the Umbra. The amount of darkening depends on a number of conditions and is very hard to predict.

The eclipse itself will be visible across all of Europe and Africa and over Eastern parts of North and South America. For those of us in Europe this will be the last lunar eclipse visible until the Total Lunar Eclipse of 28 September 2015.

UK Light Polution

Ever wondered how bad light pollution (LP) is in the UK? Well this image shows it well. It's an interesting view, across Scotland the Central belt with Edinburgh and Glasgow, are clearly visible, as are Inverness and Aberdeen, but we still have some dark sites. Head North from the Central belt and you don't have to go too far to find some dark skies. Head South too and around the borders the skies are reasonably non-polluted. Also obvious are some of the Islands around Scotland, there are plenty of dark sites there. For more info check out this site.

For a really dark site, head to the dedicated Dark Sky Park in Galloway Forest. It was established as the first Dark Sky park in the UK.

Seventh Planet - and how to see it

If you have never seen the Seventh planet, now is a really good time to try and spot it. It is visible now most of the night in the constellation of Pisces and is easily found with just a pair of binoculars. Uranus, the seventh planet from the Sun, is the third largest and the fourth heaviest in the Solar System. In classical mythology it is named after the father of Saturn and the grandfather of Jupiter. Uranus is actually just visible to the naked eye, given good seeing conditions, but it was never recognized as a planet by ancient observers because it is not very bright and it has a very slow orbit. It was in fact spotted a number of times by some famous astronomers, including English astronomer John Flamsteed almost a hundred years earlier but was always thought of as a star.

Now, as an aside, Uranus is often simply refered to as the 'Seventh Planet' simply because it stops all those "Have you ever seen Uranus?" jokes. Funny the first time you hear it, but after a few hundred times it gets a bit tiresome...

Its formal discovery was credited to Sir William Herschel in 1781 from the garden of his house in Bath. This discovery expanded the known boundaries of the Solar System for the first time in history. Uranus was also the first planet to be discovered with a telescope. A gas giant, it takes 84 years to go around the Sun at an average distance of some 3 billion kilometres. Bizarrely it is tilted by almost 90 degrees onto its side, the result of some ancient event, probably a collision early on in the formation of the solar system. It has a faint ring system, first spotted possibly by Herschel himself and confirmed during the fly-by of the probe Voyager 2. Uranus has 27 known moons in total, 5 of these are the large 'main' moons, but the Uranian satellite system is the least massive of all the gas giants.

If you get clear skies in the next few days, now is a good time. Given dark skies, good seeing and good eyesight it is just possible to spot it with the naked eye, but you need to know where to look. The best way to do it is with a pair of binoculars. Consult a start chart or an astronomical website.

On the 17th of this month is is near the Moon so remember it's position and look on a night when the Moon has moved on. The image below shows it's location as seen from central Scotland. If you do spot her, remember you are probably in the one percent of humanity who has ever seen the seventh planet with their own eyes.

Seven Sisters

As an amateur astronomer I am fascinated by the night sky, but I am equally fascinated by the mythology and legends the ancients attached to the heavens. Most of the bright celestial object have interesting histories surrounding them and at this time of year, one of my favourite surrounds one of the most beautiful winter sky objects, the Pleiades. M45, to give it's official designation, is an open star cluster containing a collection of middle aged stars. It is located in the constellation of Taurus, easily visible at this time in the winter sky. It is one of the nearest star clusters to us and is the cluster most obvious to the naked eye in the night sky. It has been easily visible throughout humanity.

To the ancient Polynesians, all the stars were put there by the God Tane, the god of the forests and the birds. He did so to light the sky up at night, so his father, the sky father, could be better seen in all his finery. However he grew jealous of one particularly bright and beautiful star so he broke it up into several pieces and cast it back into the sky. That star became the Pleiades. The Babylonian's named them “MUL MUL” or "star of stars” and some Greek astronomers thought them to be a distinct constellation in their own right. They are mentioned by Homer in both the Iliad and the Odyssey, hence another name, the “sailing stars”, used by Greek sailors to navigate. The bible mentions them three times and they are also mentioned in both Hindu script and the Koran. The Vikings thought they were a Hen with her chicks and the Lakota tribe of Native Americans had a similar view. To them they were a woman giving birth. Indian astronomers called them the “Six Mothers” but they are best known today as the “Seven Sisters”, after the name given to them by the ancient Greeks to represent the daughters of Atlas and Pleione. The count often depends upon your viewing conditions and your eyesight. Throughout history they have often been used as a test of eyesight. You could not join Napoleons army unless you could see six or seven. The Pleiades is easily visible now in the night sky from here in the UK. It rises early and by midnight is nice and high in the night sky.

Ten of the brightest stars are named but the cluster contains actually over 1000. Interesting the nearest figure given to the actual count comes in at 100. This was the count mentioned once in the bible and also in Ukrainian folklore. Modern science estimates their age at around 75-100 million years old. The cluster's relative motion will eventually lead it moving through our sky, eventually passing below the feet of Orion. Like most open clusters, the Pleiades will not stay gravitationally bound forever, it cannot. Some component stars will be ejected after close encounters with others and some will be thrown out by gravitational tides. Calculations suggest that the cluster will take about 250 million years to disperse, so we still have plenty of time to enjoy it, and maybe make a few more myths.

Capturing Andromeda

M31, The Andromeda Galaxy is a real challenge to image. It's bright and easy to see, even with the naked eye, but this brings it's own challenges. As a photographic target it's difficult because the centre is very bright but the outer edges show some very subtle detail which is on visible with long exposures. To image it is a real challenge.

I am not really a DSO photographer but have been wanting to get into this area of Astrophotography for a while. I usually prefer to shoot the Moon and Planets. The challenge is my scope (a SW200P) is a bit of an all rounder, my DSLR's are Nikon's (yes, I prefer Nikon's not Canon's - sacrilege amongst most Astrophotographer's I know) and I don't have a guided scope, I use a simple dual axis drive which means getting a decent Polar alignment, often harder than you would think. Anyway, I thought it was time to give it a go.

This week we had two clear nights in a row, unheard of for the West coast of Scotland, so I set up in my garden both nights. To counter my lack of guiding I decided to take 30 second exposures, the downside means lot's of separate images. Roughly translated that means lot's of time sitting in a chair next to the scope clicking the remote. After shooting darks and lights I must have had around 400 photos to process, with about an hour and a half of actual 'lights' or image data.

Next comes the processing. To be honest, imaging is the easy part in some respects as processing is more an art than a science. I used Deep Sky Stacker to align and stack my images and then I use Gimp to process. This image of M31 took me hours and hours, often going back and starting again... very frustrating! After a  long time I settled on a final image and this is the one shown below. Its not quite as sharp as I would like but it shows some nice dust lanes in the outer edges of the Galaxy. For a first proper go at a DSO I am quite pleased with it. Hopefully my technique will improve over time.

Keppler's Star

On this day in 1604 something strange was spotted in the night sky. Supernova 1604 was, by all accounts, a very bright event. For three weeks in October and November of the year 1604 it outshone all other stars and planets, with the exception of Venus. It's main claim to fame though was it was the last supernova to be observed in our own galaxy, lighting up the constellation of Ophiuchus on the celestial equator for about three weeks, before slowly fading into obscurity until it's remains were rediscovered in the modern era. The above image show's how the remnants appear today.

The other interesting thing about SN1604 is that it was observed by Johannes Kepler from Northern Italy. Kepler, a German who is most famous for his laws of planetary motion, was already making a name for himself as a mathematician, astronomer and astrologer and was a key figure in the 17th century scientific revolution. Kepler had heard the news of a 'new star' but did not believe the rumours until he saw it for himself. He then began systematically observing the star over the next fe weeks. He studied the star's astronomical properties while taking a sceptical approach himself to the many astrological interpretations then circulating. He noted its fading luminosity, speculated on its origin, and used the lack of observed parallax to argue that it was in the sphere of fixed stars. The birth of this new star implied a variability in the heavens that would not go unnoticed.

Interestingly this was the second supernova to be observed in a generation. SN 1572 was seen by Tycho Brahe in the constellation of Cassiopeia. Since then no other supernovae have since been observed with any certainty in the Milky Way, though many others outside our galaxy have of course been seen. For many modern astronomers, two supernovae occurring within 32 years of each other would be a gift from the heavens.

Lost Moon

More than twenty years after it was last seen, Naiad (named after a water nymph), a tiny Moon of Neptune has been seen again by the Hubble space telescope. After analysing photos taken by the Hubble, astronomers at the SETI Institute in spotted Naiad, the innermost of Neptune's moons. The 100 km moon had remained unseen since the cameras on NASA's Voyager 2 spacecraft first discovered it in 1989. It was spotted again using a series of images which were then processed to cancel out the glare from Neptune.

Now that it has been spotted again, there are other mysteries to be solved. It seems Naiad has drifted off course. These new observations show that the Naiad is now ahead of its predicted path in it's orbit, by some 80 degrees in fact.

One explanation is that Naiad may be interacting gravitationally, with the other Moons orbiting Neptune. Further images of this tiny Moon over a few years may help explain this mystery.

Draconid Meteor Shower

This time of year sees the return of one of the least known, but often best, annual meteor showers (see image above). The October Draconids, sometimes known as the Giacobinids, are a meteor shower whose parent body is the periodic comet 21P/Giacobini-Zinner.

The 1933 and 1946 showers were particuarly impressive with Zenithal Hourly Rates measuring in the thousands of meteors visible per hour, among the most impressive meteor storms of the 20th century. Rare outbursts in activity can occur when the Earth travels through a denser part of the cometary debris stream, as happened in 1998 and 2005. Rates suddenly spiked. A smaller Draconid meteor outburst occurred in 2011 although a waxing gibbous Moon reduced the number of meteors observed visually. Last years shower radar observations detected up to 1000 meteors per hour. The 2012 outburst may have been caused by the narrow trail of dust and debris left behind by the parent comet in 1959. This year, with a new moon could well be very good.

Quarter Moon

Lunar photography is a particular interest of mine. This is a Quarter Moon from earlier this year. Taken using my SW200P Telescope and a DSLR

M42

M42, the Great Nebula in Orion. Taken from my back garden earlier this year.

Scottish Astronomy Sites

A great page from Sutherland Web Astronomy showing the weather at some of Scottish Astronomy Sites I use. Also there is links to Google maps showing where they are

Also, if you are an Astronomer in Scotland, why not join the Central Scotland Observers Forum. It's a great site full of great folks!

Dark Sky Threat

I read with horror the story that Astronomers and land charities have warned that Britain's only Dark Sky Park (pictured) is being threatened by applications for wind turbines. Galloway Forest Dark Sky Park (DSP), in Scotland, secured its 'Dark Sky' status in 2009. But now the Astronomer Royal for Scotland, the John Muir Trust and the Scottish Wild Land Group have written to the Scottish government, asking it to rule out wind farms in the vicinity.

It seems there have been nine proposals for turbines near the park's observatory. Some of the applications had been rejected, but having one approved could open the door for further development. The MOD and Aviation Authority safety requirements mean that wind turbines must be illuminated by infra-red light and, in some areas used regularly for training or search and rescue, visible light illumination may also be needed. Turbines near the Gallway dark sky park could fall into the latter category, and the campaigners said it would affect both the ability of astronomers to use sensitive equipment, and the visibility of stars, galaxies, comets and northern lights. The group has called for the park to be given protection similar to that afforded to areas of wild land, and has called on the Scottish government to update planning policy to rule out the construction of wind farms around the park.

This facility is the only Dark Sky Park in Britain, although both Exmoor and the Brecon Beacons national parks have been awarded Dark Sky Reserve status. Gallway DSP is also home to the world's only publicly accessible, research-grade observatory within a Gold Tier Dark Sky Park. Problem we have is the DSP was open by the Scottish government and praised for being a first, this same government is also pushing renewables such as wind turbines.

I urge anyone out there with an interest is saving our Dark Sky Park to get involved in promoting this threat to our world class site. If we loose it, we wont ever get it back

First Light

Like all good telescopes, all good blogs have first light. It's that moment when they get used for the first time. I have had blogs before but after a while I tend to stop writing, it's the pressure of time really. This time I don't intend to pressure myself to write as much as possible, I will just write when I can. So, here's to Scottish Astronomy, that constant battle of dark skies versus terrible weather.