His talk was entitled “Hot Results on Cool Galaxies: The Hidden Universe Revealed.” Robert Kennicutt is the Plumian Professor of Astronomy and Experimental Philosophy at the University of Cambridge and the Director of the Institute of Astronomy.

The talk was very interesting and Professor Kennicutt started off by talking about William Herschel’s experiment which discovered that there was heat beyond the visual spectrum of colour and into the infrared.

We were told that most IR radiation is blocked by the Earth’s atmosphere, and that viewing objects in space in the Infrared from ground telescopes is also very difficult, as everything around the scope glows. This has meant that the best way to conduct IR experiments is from space.

Some of these IR telescopes include the IRAS in 1983, ISO from 1995 to 1998, Akari from 2006 to 2007 and the Spitzer telescope from 2003 to 2009.

Professor Kennicutt also took us through various findings of a Spitzer survey (SINGS) and then told us about the new Herschel telescope with it’s 3.5m silicon mirror as well as the Planck microwave satellite which are going up into space together at the same time via an Ariane 5 rocket.

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He mentioned that Supernova give off enough light to be seen for about 4 to 5 months, such as supernova 1987A and supernova 2003gd in M74.

When stars are born they are hot and blue in colour and are made of helium and hydrogen. At this point other gas and dust is blown away.

The Red Supergiant then gets a carbon oxygen core and then an iron core is created, the centre is then hotter and denser than before. After this the star then collapses down to  a supernova, at which point nickel is produced. 

We were also told that Betelgeuse is actually a Red Supergiant, so think of that next time your are observing it.

The talk about Supernova was very in-depth and quite complicated for me, and I was lost at some points, but none the less a very good talk with lots of good movies of the life span of stars up to the point when they go nova.

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David gave a personal insight into the history spaceflight. He showed us lots of photos of himself together with many famous astronauts, including ten Apollo astronauts of which seven have visited the Moon.

David started by talking about the history of rockets including the use of rockets by the Chinese Mongols in the 13th Century and the Congreve Rocket in 1805.  He also discussed how rockets work, such as how liquid fuel and liquid oxidizer are pumped together.

He also mentioned the v2 and A4 rockets of World War II and how gyroscopic guidance was introduced. Werner Von Braun was said to be a major influence in US missile design in the 1950′s and 1960′s including working on the Redstone and Saturn rockets. It was also mentioned that Sergei Korolev turned the v2 rocket into the R7 rocket.

David’s presentation was good as it included a lot of video content of shuttle and rocket launches. It was good to learn all about the various NASA launches that have been made.

Overall, David was a very interesting speaker and very funny as he told lots of jokes, a speaker I would like to hear more from.

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Aurora can actually be seen from space, and some images demonstrated this, with views from the NASA shuttle. Aurora were actually treated with fear in historical times.

Early research showed that aurorae actually extended around the poles of the Earth in a ring ~(as shown in the accompanying image), and the ring (more commonly called the “aurora oval”) does actually move, so depending on where it is, you may see an aurora.

Aurora’s have actually been visible from the UK, and we were told that in the UK we may have the chance to see aurora up to three times a year, but cloudy nights decrease our chances of viewing one.

The Earth’s aurorae are actually triggered by the Sun, as the solar winds interaction with the magnetosphere is mapped down into our atmosphere. We were also informed that there are different colours to the aurorae. A red aurora means that the aurora is very high in the atmosphere, whilst the middle height colour is green and a low aurora provides a purple colour in the sky.

We were told that Coronal Mass Ejections (CME’s) create the Earth’s aurorae activity, but other planets also have aurorae including Jupiter which creates its own aurorae with a lot of help from the volcanic moon Io. Saturn also have aurorae as well, but they are 100x less active than Jupiter’s.

Overall we learnt, that anything with magnetic fields has aurorae. This was a great talk that told us everything we wanted to know about aurorae, and even more besides.

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As well as a full day of lectures there were also a number of stalls selling astronomy books, astronomy hardware and of course a number of meteorites. I was amazed to see the actual number of meteorites that you could purchase, which included rock from the Moon and from Mars.

There were lots of activities for children, including making model craters and the children also received their own iron meteorite for a small fee.

I attended three of the five talks during the day. The first one was by Dr Caroline Smith who was from the Natural History Museum in London, and she looks after nearly 2,000 meteorites in the national collection. We were told that there are over 35,000 meteorites found so far, and that 34,000 of these have come from the Antarctic. The desert of the Antarctic is a great place to find meteorites as they stand out so well in the snow and the dry conditions enhance the preservation of the meteorites, as in a normal country within 20,000 years a meteorite can breakdown and disappear.

We were also told that meteorites can give us the age of the solar system and details on the evolution of the solar system.

It was interesting to find out that stony meteorites are broken down into two groups; achondrites and chondrites. Achondrites have undergone melting whilst Chondrites have not. It was also mentioned that Calcium Aluminium Rich Inclusions (CAI) allow you to date the meteorite.

I also attended a talk entitled “Do you come here often? Dirty snowballs: Comets” by Jonathan Shanklin and a talk by Nik Szymanek, which unfortunately I had seen before, but it was worth sitting through it again, I can’t get bored of seeing Nik’s astrophotography images.

Overall it was a great day, and even better it was all free.

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The first talk was by Andy Fabian entitled “The Power of Black Holes”. Andy talked about the possibility of their being a black hole in the middle of our galaxy which can be viewed on ly in infrared as there is a bulge in the middle of our galaxy. He went through the history of who discovered black holes, such as John Michel who in 1784 was the first to work on the possibility of a black hole. He also talked about astrophysical black holes which have olny mass and spin and about gravitational red shift.

The second talk was by Nik Szymanek entitled “Photographing the Night Sky”, which was really why I attended the whole day, and his talk did not disappoint, with lots of amazing astrophotography images in the talk and his talk also contained an 8 minute video. I think in the future I would like Nik to get a bit more technical and actually tell us exactly how to take his type of magical photographs.

Another talk was by Barrie Jones entitled “The Seach for Extra-Terrestrial Life”. This talk covered the search for Exoplanets, which are mainly found by radial velocity. He also told us about what needs to exist on the planet to allow us to find a habitable planet, such as temperature, carbon and water together or ozone and oxygen photosynthesis or oxygen and methane.  For us to find technically intelligent aliens they need to have binocular vision, hands and brains.

The final talk was by Somak Raychaudhury entitled “Einstein’s Outrageous Legacy – Black Holes, Cosmic Illusions and Dark Energy”, but I did not stay for this, as I think I had already seen the speaker at a Cambridge Astronomy Association night.

There were lots of stalls in the main foyer, including stalls from Astronomica, Green Witch, Cambridge University Press, Nik Szymanek and many other book stalls as well as stalls from the national and other local astronomy clubs.

Green Witch set up a Coronado PST telescope outside which many people used to get their first view of the Sun, this is the image I managed to get by putting my Canon 400d up to the eyepiece of the Coronado PST.  There was a really good solar flare coming from the Sun but this does not seem to have come out on the photograph.

Tea, Coffee, soft drinks and biscuits were served all day long, never have I drunk so much tea in one day! The weather was perfect and during lunch there was a tour around the on-site telescopes. Here are some photographs I took of the various domes, namely the Northumberland, 32 inch, Schmidt camera telescopes as well as the Institute of Astronomy library building.

There was also an imaging competition, as well as a raffle. Overall a good day out and I am glad I attended, especially as the location of the day was local for me.

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A diagram of the sun explained each named part of the Sun including the photosphere, chromosphere, filament, convective zone, radiative zone and prominence.

It was also explained to us that the solar material in the Sun is a plasma and so conducts electricity.

The lecture included of course sunspots, and it was interesting to find out that the actual recording of sunspots did not begin until 1610. William Herschel thought that sunspots were openings in the Suns atmosphere.

The centre of a sunspot is called an Umbra whilst the outer part is called the Penumbra. The Umbra appears darker as it’s cooler than the other parts. We were also told that sunspots appear in pairs which have opposite polarity. There is an 11 year sunspot cycle and the polarity of the sunspots also reverses after 11 years.

The talk then asked the question can we predict solar activity? This section ended by quoting “At the moment there appear to be too many uncertainties in the current solar cycle models to allow for sound predictions”, which was taken from a Nature article.

We were told that solar winds are when the Sun expels a million ton of particles which are threaded by magnetic fields.

Solar activity can also cause problems for us on the Earth, as geomagnetic storms induced by solar events can interrupt radio, satellites, cause power cuts and damage pipelines. . In March 1989, 6 million Canadians lost power for 9 hours because of the Sun’s magnetic activity.

Overall this was an interesting talk that taught me more about the Sun than I knew.

Alice first came to the UK to follow a masters course at Cambridge University in 1999. Then, after a two year break teaching physics in Madagascar, she came back to do my PhD in the Department of Applied Mathematics at Leeds University, which she completed in 2006. Alice is currently working as a post-doctoral research associate in Leeds; where her main interest is trying to understand the origin on large-scale magnetism in astrophysical bodies.

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Marc began by explaining what actually is defined as a black hole; known to have a most extreme case of gravitation, where the mass is concentrated in one point and it is surrounded by a spherical horizon.

Marc also had an interesting slide detailing the flow and gravity pull of a black hole which included details on subsonic flow, supersonic flow and about the sonic horizon.

There is believed to be a black hole at the centre of our Milky Way.

We were told that the effects of Massive Black Holes (MBH) on stars can be used to reveal the presence of Massive Black Holes and determine their properties. We also learnt that stars around Massive Black Holes in a spherical nucleus produce a rosette orbit and that as a star is close to an MBH you get a Keplerian ellipse.

Stellar Massive Black Holes are the end product of evolution of stars greater than 20 to 30 suns, and they are only 1-2 stars in 1,000.  This version accumulates around the Massive Black Holes.

One interesting future piece of research is to be the LISA spacecraft which is being designed to measure the mass and rotation of Massive Black Holes. IT will measure Gravitational Waves (GW) which are emitted when a black hole passes a massive black hole.

A Gravitational Wave is a contraction of space in one direction and an expansion in the other direction. Gravitational Waves also produce contraction and expansion of space itself.

The LISA spacecraft consist of three spacecraft that will form the shape of a triangle in space in an orbit similar to that of the earth.  The distance between the spacecraft will be 5 million km apart.

LISA will detect gravitation waves by comparing distances between “test masses” in different directions using lasers. A similar research project on the ground has been executed called LIGO in the US and VIRGO in Italy.

Overall the talk was very in depth and I got a bit lost half way through with all of the formulae and physics, but the talk was littered with interesting images, simulations and videos.

I look forward to see the launch of LISA in the future, and to see if it will be possible to detect gravitational waves as well as if it will be possible to keep the three spacecraft evenly spaced across space in order to constantly create a perfect triangle.

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This week we had a talk by Roderick Willstrop entitled “History of the Telescope”. Roderick took us through 400 years of the main developments of Telescopes and the major telescopes that have been built, including Space Telescopes.

Roderick went through a long list and dates of the major advances over time, these included:

Hopefully I wrote all these notes and dates correctly, although there may be some errors, if anyone wants to correct me, feel free to do so.

After the talk, we went out and visited the 3 mirror telescope (3MT) which Roderick actually designed.

The Three Mirror Telescope (3MT)

The Three Mirror Telescope (3MT) has been developed at the Institute of Astronomy by Dr. Roderick Willstrop. Its optical design is unique because it is the only form of telescope which combines the three advantages of a wide field of view, very small sharp images, and all-reflection optics.

Reflecting telescopes have been built with apertures up to 10 metres, but they have fields of view limited to 40 arc minutes (Ritchey- Chretien two-mirror design) or 1 or 2 degrees with a 3- or 4-lens Wynne corrector near to the focus of the main mirror. Schmidt cameras can give fields of view of 7 or 8 degrees, but their apertures are limited to about 1.3 metres because they use a thin glass lens large enough to cover the whole aperture.

The 3MT has a field of view 5 degrees in diameter, and the ray- theoretical image size is less than 0.33 arc seconds everywhere, and less than 0.1 arc seconds over the central 1 degree of the field. Because no lenses are needed the images are perfectly achromatic, and furthermore it is possible, in principle, to build this telescope with a larger aperture than any Schmidt camera.

The design is based on a simpler one discovered in 1935 by the French optician Maurice Paul and rediscovered independently in 1945 by the American James Baker. The original Paul-Baker design had a paraboloidal primary mirror, a convex spherical secondary mirror and a concave spherical third mirror. If the aperture of the primary mirror was f/4, it would have given acceptable images, and a field of view of about a degree.

The good performance can be explained as follows: if the second mirror were a convex paraboloid (instead of spherical) the light from a distant star would be made parallel again after the second reflection. (This arrangement of two coaxial and confocal paraboloidal mirrors was described by Mersenne in 1636.) The third mirror would then also have to be paraboloidal to focus the light, and the field of view of the whole system would be no larger than that of a single paraboloidal mirror. The essential feature of the Paul-Baker design is that the second mirror is spherical, so the light is not exactly parallel after the first two reflections, but is deviated in just the same way as by the corrector lens of a Schmidt camera. Then the third mirror must also be spherical to focus the light, and a large field of view with sharp images is obtained. This telescope has also been called the Mersenne-Schmidt.

Baker suggested that the Hale 200-inch (5.08 metre) telescope might be given a wider field by using two auxiliary mirrors. It would not have been acceptable to enlarge the central hole in the irreplaceable 200-inch primary mirror. The third mirror, 2.1 metres (84 inches) in diameter and weighing one or two tons, would therefore have been mounted directly above it, so the system was never built. The field of view could have been just over 1 degree. In the f/3.3 Hale telescope, it would have been necessary to modify the shape of the secondary mirror to retain small, sharp images.

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The talk began with a look at Hubble’s galaxy classifactions as well as a mention to Fritz Zwicky who studied the Coma Galaxy Cluster in 1933 which was 300 million lightyears from Earth. At this time Fritz put forward the theory that unseen matter must exist, which we now call Dark Matter.

Lindsay also told us about the effect ‘RedShift’ which is when the speed at which a galaxy moves away changes the colour of the light. A red galaxy is moving further away, whilst a blue one is closer.

We were also introduced to the furthest galaxy away from us, which was discoverd by the Subaru telescope which is a Japanese telescope located in Hawaii. This furthest galaxy is said to be 13,000 million lightyears away.

We also got an explanation as to what “Gravitational Lensing” is. Mainly that mass distorts space-time and that galaxies form  where dark matter exists in order to trap gas and make stars. It was also noted that galaxy clusters are so large that they warp space-time around them.

The Schmidt Camera Telescope

After the talk we went out to see the now unused Schmidt Camera telescope. It has not apparently been used since taking images of Halley’s Comet in 1986, and may be moved to Wales, to be used in the project for imaging potentially fatal asteroids coming towards the Earth.

The instrument itself was built in 1952 by Grubb-Parsons of Newcastle-upon-Tyne and replaced an older telescope in the existing dome, which had been made by T. Cooke & Sons Ltd. of London & York at the time of the move of the Solar Physics Observatory from South Kensington to Cambridge.

It is a `Classical Schmidt’ – the simplest and most efficient form of the ingenious wide-field camera invented in 1930 by Bernhard Schmidt of Hamburg Observatory. Light from the sky falls upon a 61 cm (24-inch) mirror with a spherical reflecting surface, at the bottom of the tube. It is reflected to a focus in the centre of the tube and half-way up it, 163 cm (64 inches) from the primary mirror. At the focus a photographic plate P 15 cm (6 inches) in diameter, which must be bent to fit a curved surface, records the star images in an area of sky 5 degrees in diameter. (The full Moon is half a degree in diameter.)

Without any further optical element the star images would be of poor quality owing to “spherical aberration”: light falling near the edge of the mirror would come to a focus too close to it, and light falling near the centre of the mirror would be focused a little too far away.

Schmidt’s invention was to place at the centre of curvature of the primary mirror, near the top of the tube, a weak meniscus lens (in this case 43 cm (17 inches) in diameter) with one aspheric optical surface: this makes the light which passes through it near the edge diverge slightly, lengthening the focus of the outer parts of the mirror, and makes the light passing through near the centre converge, shortening the focus of the centre of the mirror.

This optical combination of lens and mirror forms a fast, efficient camera giving sharp star images of uniform quality over the full 5 degrees field. It is an ideal sky-surveying instrument; by contrast the 36-inch (91.4 cm) telescope, with its paraboloidal mirror of 4.1 metres (162 inches) focal length (f/4.5), has a field of view only 7.2 arc minutes in diameter with images smaller than 2 arc seconds.

The auxiliary 15 cm (6 inch) telescope is for guiding. The exposure time is usually of the order of 10 minutes, and during this time the image can wander about on the photographic plate mainly because of irregularities in the refraction in the earth’s atmosphere. These are corrected by maintaining a star image at the intersection of the cross-wires in the guiding telescope.

The Palomar and U.K. 48-inch (1.22 metres) Schmidt cameras which were used to make the all-sky surveys (now kept in the Cambridge Astronomical Survey Unit) have apertures nearly three times as large as our telescope, but focal lengths (and tubes) only twice as long. Only one Schmidt camera (the 53-inch (1.35 metres) at Tautenburg, Germany) has ever been built larger than these two.

The reason is that, if a Schmidt camera is simply scaled up, its image size is also scaled up, and as Bernhard Schmidt himself predicted, the 48-inch Schmidts are close to the practical limit. The main image defect arises because the thin lens can correct the “spherical aberration” of the mirror exactly in only one colour of light, (usually blueish green), red light is under-corrected, and blue or ultra-violet light is over-corrected.

To minimise the length of the tube, and so the size and cost of the dome, the 48-inch Schmidts have been made with an aperture of f/2.5 (this one is f/3.7) and the “spherical aberration” of the mirror is then 3.2 times as large as in the camera.

Three of the largest Schmidt cameras have been fitted with “achromatic” lenses which reduce the residual colour errors, but astronomers now use very fine-grain emulsions, and wish to observe a wide range of colours of light, so these large Schmidts are still at the practical limit of size.

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