The Lord of the Rings

The Lord of the Rings itself: Saturn. Taken last night, despite a blazing full moon, freezing conditions and frost clouding up my lenses. I've waited half a year to capture this video on my telescope - Saturn was always below or too low on the horizon. But this was well worth the wait - enjoy!

I processed the video above with the Registax astronomical image stacker to see if I could get a bit more detail and obtained the image below. You can just about make out the dark cloud band in the northern hemisphere, as well as the shadow cast by the planet on the rings. Unfortunately, I was not able to resolve Saturn's rings individually or even show Cassini's division (the gap that divides Saturn's rings into two parts) - probably because I hadn't focussed the telescope sufficiently well on the night. Will try harder next time!

The Astronomer's Apprentice: Getting your child to LOVE science and astronomy

There are perhaps very few gifts that a parent can bestow upon his child that is as precious and as valuable as a life-long love for science. And there is no better and easier way for you to introduce a child to the wonders of science than through astronomy.

You don't really need to get your child his or her own telescope to have your child interested in astronomy. But he or she having one of his or her own would make it all that more fun and exciting. Rishon's own telescope is a small 60mm refractor, with a tiny 0.96-inch eyepiece with a 10mm focal length. This particular scope only cost less than £7 from Oxfam, so you don't have to spend too much on these toys. And they are essentially just toys - they are completely useless for serious astronomy. I had to tell Rishon not to expect to see breathtaking vistas such as the rings of Saturn or the cloud belts of Jupiter - if he wants to see those, he can see them through Daddy's telescope. But he could use his own scope to pick out those planets from the night sky and they do provide some quite nice views of the moon and its 'seas' and craters. More importantly, it also allows him to explore the instrument on his own, learn about its parts and how to use them and prepare for when he is old enough to get his own 'proper' scope.


You'll see on his window sill that he also has a smaller spotting scope. Again, it's just a plastic toy - but it can be used for wider field views of the stars and handy for terrestial viewing as well.

Perhaps the first place to start if you want to inculcate a love for astronomy and science is the child's room. A boy's room is his castle and decorating it with a few carefully-selected astronomy objects will go along way to making your child comfortable with and enjoy what could easily be perceived to be a boring old school subject. Take this solar system model that hangs over his ceiling light, for example. Not only does it give him a reasonably accurate illustration of what solar system objects looks like, but it also glows in the dark when he goes to bed. Now, how cool is that?!


And the solar system model below is even more cool. It's like your own solar system navigation computer. You press a button on the keyboard and the relevant planet will magically light up, with a computerised voice telling you all about the planet in question. Press another button and you can sit for a little test, where the computer will ask you a multiple choice question and you have to press the correct button before proceeding to the next space exploration challenge.

Every parent knows how kids sometimes like to wallpaper their rooms with posters. Now, I have categorically state that these posters of starships are not just a refection of his keen interest in Star Trek acquired by constant exposure from his dad - they do have some valuable educatonal value too! Propulsion systems, navigational arrays, science laboratories and communications beacons are not just found on the starship Enterprise of the 24th Century - you'll also see them on the Internatonal Space Station or the space shuttles of today.

Well, okay, Rishon may be a little too young to appreciate the complexities of anti-matter physics and the search for the elusive Higgs boson 'God Particle'. But the poster does have a great picture of Mr Spock! And his Star Trek-themed pillow and duvet set below is both warm and comfortable ... inspirational, yet quite functonal ;)

Be honest now - how many kids would not like the idea of having a real-life space map on the wall of their room? This is Rishon's planisphere - basically a star chart in the form of two adjustable disks that rotate on a common pivot and can be rotated to display the visible stars in the night sky for any time and date. Aside from getting a kick out of spinning the two disks round and round (which Rishon loves to do), he also inadvertently learns how to recognize stars and constellations in the night sky.

And the little cardboard cut-out diorama here was something Rishon got from the local Mad Science club he attended and shows how the different stars in the saucepan-shaped Big Dipper are actually laid out in 3D space.

Like real-life astronomy, Rishon's little dome gadget below requires absolute darkness. Switch the room light off, make sure not a sliver of light enters the room from outside, switch the gadget on and you will actually see the stars and constellations of the Northern Hemisphere projected on your room celing and walls! The transparent plastic dome has a map of the northern sky embossed on it and a light bulb projects a negative image of the map all around the dark room, rotating it slowly around the polar axis. Daddy uses it too - when the night skies are blanketed in cloud and he can't get out to play with his telescope, this is the next best thing!


And below is an ordinary plasma lamp - just the thing to turn any ordinary five-year old boy's room into the laboratory of a mad scientist! Also a good prop to use when trying to explain to your boy the basic principles of electricity, electromagnetic fields, particle theory, ions, states of matter - oh, and of course what the plasma phase inducers do in the warp engine assembly of a Galaxy-class starship!

Kids love computers and you can use this love of computers to get them to love astronomy too - even if it's just computer games. There's nothing Rishon loves to do more than join Dad when he's zapping Klingons and Borg cubes on Star Trek Online or Freelancer. But we also do take a breather from inter-galactic warfare now and then to have a close look at asteroid belts, black holes and supernovae.


There are also a lot of websites that have online games that teach astronomical and space exploration principles to very young children. The NASA Kids Club website  , for example, has games that lets kids manage fuel payloads for the space shuttle, build space station modules, explore microgravity environments and build the International Space Station from scratch!

Computers aside, there's of course the old-fashioned but just as effective way of making your child learn more about astronomy - books! There are a huge number of books for young children that introduces them to the joys of astronomy. Rishon particularly enjoys those produced by Ladybird (because they're easy to read for a five-year old) and Wiley's Visual book series (because they have loads of colourful pictures!).

The Ladybird book 'The Night Sky' in particular has special meaning for me - this was the very same book that I read when I  was six. Published in 1965, it was a good, simple read and absolutely beautifully illustrated in the old classic Ladybird style. The first thing you see when you open the book is a simple star map with the most exotic names like Andromeda and Pegasus, and a menagerie of dragons, bears, serpents and scorpions lurking in the skies above. Turn the page and you behold Saturn - and you've only just reached the title page. The light of a billion suns, galaxies and nebulae awaited in the rest of the book, all the wonder of astronomy, the beauty of art, the awe of the natural word, in a slim 52 pages. A life-changing book for me and I hope it's the same for Rishon.

And talking about life-changing books, here's another one for me - Antoine de Saint-Exupéry's 'The Little Prince'. A little prince leaves his home planet to see how the rest of the universe is like, exploring six planets before he ends up on Earth. Though ostensibly a children's book, the Little Prince makes several profound and idealistic observations about life and human nature. With phrases like "One sees clearly only with the heart - what is essential is invisible to the eye" and "what makes the desert beautiful is that somewhere it hides a well" - this is no ordinary children's book about exploring stars and planets!


Other than reading, children of course also like drawing and writing (and especially drawing). So get them to write about what they read and what you teach them. I have my own astronomical observer's log book and taking pride of place within it are the inciteful astronomical notes from Rishon below 

I also try to get Rishon involved in my own astronomical activities. As Rishon goes to bed at 7.30 PM, it doesn't really leave a lot of time for him to be out in the back garden observing the night sky with me and even when there is time during the early nights of winter, it can also be too cold for him to be out. Nevertheless, he still enjoys helping me set up my equipment before the night's observing starts. And he gets a real kick the next day looking at any pictures I may have taken - especially since he helped Daddy set it all up.


And you don't even need a telescope to enjoy the night sky with your son. Just sit down with him one dark night and quietly explore the amazing array of lights, colours and lines that are painted on the vast velvet canvas above you. I really can't think of a better father-son bonding exercise than showing your son the naked eye wonders of the night sky.

And if extreme room make-overs, toys, gadgets, games or books don't seem to work, just show him one of these in your telescope eyepiece one night. He'll be hooked for life!.

Oh yes, my final tip for you - start 'em young!

Twin Beacons

March this year was perhaps be the best month to watch the planets for years to come - it was when the two brightest planets in the night sky come together for a stunning conjunction. For the Northern Hemisphere, mid-March 2012 presented the best time to see a Venus-Jupiter conjunction in the evening for years to come. The night sky's two brightest planets – Venus and Jupiter – were near each other in the west as soon as the sun went down, like twin beacons. The next Venus-Jupiter conjunction after this one falls on May 28, 2013 but it won’t be as spectacular then as they are in 2012 because it will be in daylight! This image was taken on March 11th at 10 pm - Jupiter is on the left and Venus on the right. The best night to see the conjunction was actually March 15th - unfortunately, I was in Geneva for a bloody meeting that day :[

This image of Sirius below was taken at the same zoom, aperture and exposure settings as the previous image of Venus and Jupiter. The usually stunning Sirius - the brightest star in the night sky - pales by comparison.

Measuring double stars

Let's have a look at three double stars I have observed and recorded below, see how we can do some real science with them. At the top are Mizar and the dimmer Alcor in Ursa Major. Bottom right is Mizar resolved to a higher magnification with a 2X Barlow lens and split to Mizar A and B. And bottom left is Cor Caroli, split to α² Canum Venaticorum, the fainter α¹ Canum Venaticorum.

 

Let's start with Mizar and Alcor. The simplest method to measure binary star characteristics is by using what is called the drift method. This method consists of taking a long exposure image or a video recording of a pair, so that its movement across the skies is recorded. The lines produced by the drifting star images (called the drift lines) define the east–west line of travel of the pair in the image.

Once I captured a video of the binary with my CCD imager, I then extracted the first and last frames of the video and saved them as two separate image files. Merging these two images into one single image produces the image below.

Draw a line joining the primary star from the first frame with the primary in the last frame (and repeat with the secondary star). This produces the drift line which defines the east–west line of travel of the pair (in blue above). Draw another line perpendicular to this (in white here( - this would now point to celestial north. Then draw a line joining the primary and secondary star (in red above). You can now measure the position angle (PA) of the binary directly with a protractor. Knowing the pixel resolution of your optics and using simple O-Level coordinate geometry and trigonometry, you can also now calculate the separation (the distance between the two stars, in arc seconds). Simples!

The visual method described earlier will work well for widely-separated pairs like Mizar and Alcor. However, with closely-spaced pairs and pairs where the stars nearly align with the east–west line, the magnification and scales you will be working with may not give you accurate results. In these cases, you may want to use specialised software that will take a video image of a travelling pair and do all the calculations for you at the pixel level. Let's try this with Mizar A and Mizar B below.

 

One simple (and absolutely free!) software programme you can use is BinStar, by Ed Hitchcock ( see http://www.budgetastronomer.ca/index.php?page=binstar ). Just load your video file into the programme, click on the primary star and then click on the secondary star.

Click on 'GO!' and BinStar will play the video and trace the drift line of the binary pairs as it moves across the sky, while automatically working out the position angle and separation.

An even more sophisticated programme (and free as well) is Reduc by Florent Losse (see http://www.astrosurf.com/hfosaf/Reduc/Tutorial.htm ). Let's now examine Cor Caroli below using Reduc.

You first load in the video file and Reduc will then extract all the frames from the file and save them as individual image files.

Reduc then reduces each frame individually to produce a pretty accurate drift analysis, below.

Position angles and separations are then calculated for each frame - you can save these results and manipulate the data in whatever way you please!

A double dip in the BIg Dipper

Ursa Major is one of the most recognizable constellations in the northern sky. The tail end of the constellation is called by our American cousins the Big Dipper because it looks just like a huge water ladle in the sky. This picture was taken with a Camedia C2040 without the use of a scope (I had to wait until 3 in the morning to take this picture as the bloody neighbours had all their bloody lights on all night until 3 and it was polluting my views). The star in the middle of the 'handle' is called and if you look really carefully (without telescopes or binoculars), you might even see two stars. That's because there is a second much fainter star called Alcor. The ability to resolve the two stars with the naked eye is often quoted as a test of eyesight - if you can't see two stars, you probably need glasses!

Okay, time to use the telescope now, with a Neximage CCD imager and magnification equivalent to a 6mm eyepiece. The two stars can be clearly seen now. They are about 1.1 light years apart (that's 6,500,000,000,000 miles!) but are what's called a true binary system - that is, they orbit around one another. But that's not at all. Mizar (on the right) may look like one star but it's actually two - Mizar A and Mizar B. Mizar A is closer in the foreground and shines so brightly that's its luminance blocks out Mizar B, which is slightly behind it. 

Let's take a closer look at Mizar. Stick on a 3X Barlow lens to the CCD imager and all is revealed - a binary star system within another binary star system. Mizar A is the larger star that we see in the foregound. Not only that - stereoscopic studies have shown that Mizar A actually has another companion star that, unfortunately, is too close to it to resolve with any earth-bound telescope.

Seeing double: The joys of binary stars

A binary star is a star system consisting of two (or more) stars orbiting around their common center of mass. We had cloudless skies over Longstanton for the first time this year, so I managed to have a quick look at a few binary star systems last January (despite the glare from the gibbous moon and bloody freezing cold).  The first is Cor Caroli, which can be found in the crook of the Big Dipper's handle, just to its right, standing almost due east. The star is a true binary, consisting of two stars orbit each other (each orbit is estimated to take about 7,900 years). These two stars are designated Alpha-1 (the fainter of the two) and Alpha-2, and are thought to be about 650 Astronomical Units apart (that's 650 times the distance between the Earth and the Sun).

And here's a processed still image of the video:

A close-up of Cor Carioli. Cor Carioli (the heart of Charles) is named after Charles I of England, who was executed during the English Civil War in 1649. According to legend, this star brightened when his son, Charles II, return from exile on May 29, 1660. Cor Carioli is in fact a variable (it's brightness changes). The strong magnetic field of these stars are believed to produce starspots of enormous extent, which cause their brightness to vary considerably during their rotation.

We now come to Polaris below, so named due to the position of the star near the north celestial pole. Point a telescope at any other star and you will see it moving across your field of view, but point it at Polaris and it stays dead still. This made it a reliable beacon for early navigators. Polaris actually consists of one bright star - Polaris A - and two companion stars. The brighter of the two companions, Polaris B (the faint star on the left of the picture), is about 2000 Astronomical Units (AU) away from Polaris A (that's 2000 times the distance between the Earth and the Sun). Polaris A actually has another close companion star orbiting with 5 AU from the primary but it is too close to the primary star to be resolved visually.

Not everything that looks like a double is in fact a binary star system. Procyon below IS a binary star system, consisting of a white main sequence star Procyon A, and a faint white dwarf companion Procyon B. However, that faint star to the left is NOT Procyon B. The separation of Procyon A and B is 15.0 AUs - a little less than the distance between Uranus and the Sun - so Procyon B would be too faint and too close to the 'glare' of Procyon B to be observable on an 80mm scope. At a distance of 11.46 light-years away from earth, Procyon is one of our near neighbours.

The Colour of Stars

You might think that the stars that we see in the night sky are all white but that is only because our eyes cannot easily distinguish colours when objects are very faint. In reality, the night skies are ablaze with colour, with stars ranging from cool blue hues to fiery reds. Take a look at the image of the constellation Orion below. In particular, look at the top left star Betelgeuse and the bottom right star Rigel. They might look white initially but even on a fast 2-second exposure without the aid of a telescope, closer inspection of the picture can reveal a glimpse of reds and blues.

Zoom in with a telescope and Betelgeuse can now clearly be seen below as a fiery red star. That's because Betelgeuse is classified as a Class M red supergiant, one of the largest stars known. Strange as this may seem, fiery red usually indicates a cool star that is losing its radiation and dying out, while cool blue stars are the hottest, youngest stars. Betelgeuse is in fact in the last stages of its life and is expected to go supernova any time in the next million years (which is a very short time in stellar terms).

You can go deeper into the mysteries of star colours with spectroscopy - this is the science of determining the properties of a star by analysing the electromagnetic light radiation from it. By attaching a special optical filter called the Star Analyser 100 to my telescope eyepiece, I am now able to see the the colour spectrum that is unique to light radiation produced by Betelgeuse. The Star Analyser is basically a diffraction grating (as you would see on the surface of a CD or DVD) that is mounted in a standard 1.25 inch optical filter cell.

The image of the spectrum produced by the Star Analyser can be further analsyed using special software to reveal the spectral profile of the star that will tell you a lot about the star you are observing. The broad shape of the spectrum gives information about temperature - for example, this spectrum of cool Betelgeuse is quite different to that of hot Sirius. Narrow absorption (dark) or emission(bright) lines on the spectrum tell us about the chemical elements that are present in the star and how they are behaving - for example the spectrum of Betelgeuse reveals the tell-tale signature of molecules (and not just hydrogen atoms) in its atmosphere. The software I used to produce this spectral profile is a free product called Visual Spec - see http://astrosurf.com/vdesnoux/

Now let's take a look at the star in the opposite end of Orion, Rigel. Seen through the telescope below, you can clearly see that this is a pale blue star. Rigel is in fact a Class B blue supergiant. While blue supergiants are much smaller than their red counterparts (like Betelgeuse), they are amongst the hottest and brightest stars in the known Universe.

 

Attach the Star Analyser to the front of the CCD imager eyepiece and you'll see the spectrum produced by Rigel is quite different from that of Betelgeuse - with the bands in the blue end of the spectrum much stronger and the red band being significantly weaker.

Analysis of this spectrum with Visual Spec shows a presence of neutral helium and moderate hydrogen lines. Ionized metal lines include Magnesium II and Silicon II.

Let's now take a look at Sirius - the Dog Star. Sirius is the brightest star in the night sky and that is primarily because of its intrinsic luminosity and its proximity to our Earth. At a distance of just 8.6 light years away, the Sirius system is one of Earth's near neighbors. It is a Class A star - amongst the more common naked eye stars - and these are white or bluish-white, as you can see from the image below.

The spectrum produced by Sirius:

Analysis of Sirius' spectral band reveals strong hydrogen lines and also lines of ionized metals (Iron II, Magnesium II, Silicon II) and the presence of Calcium II lines.

And I can't talk about the colour of stars without of course mentioning our very own star - the sun. The sun is sometimes called a yellow star and it does indeed appear yellow to us on Earth (viewed through our atmosphere) but the Sun's own intrinsic color is white (aside from sunspots), with no trace of color. And if you want to do a spectral analysis of the sun, there's no need for a Star Analyser 100 to produce an image of its spectrum bands - just look out for the rainbow in the sky just after it rains!