Tuesday 27 March 2012

Naming The Stars

About 4000 stars are visible on a really dark, clear night. If you know that stars, you can mention them by name. "There's Sirius, the brightest star in our night sky." Or, "Over there is Polaris, it's only the fiftieth brightest star, but it always shows which way is north." (If you want to drive your friends mad, suggest they count out the first 49 bright stars to find Polaris.)

Sirius as a name come from ancient Greek, and means bright in that language. The star is located in the constellation of Canis Major, the Big Dog. There are two other dog constellations, Canis Minor, the small dog, which has a very bright star named Procyon in it. Procyon means the leading dog. Finally we have Canes Venatici, the hunting dogs, which lacks bright stars, although it has three visible stars with names, Cor Caroli, Chara, and La Superba. There are also four named galaxies, the Whirlpool, Sunflower, Croc's Eye, and Silver Needle. Note the galaxies all have names in English. That is because other galaxies were only recognized after 1923. The names do not come down from centuries ago.

Ursa Major, the Big Bear, has the most named stars, 22, also with four named galaxies. Most of the star names, as is true throughout the sky, derive from Arabic. Dubhe, for example, simply is the Arabic word for bear (perhaps not the most useful Arabic word to know if you find yourself in Cairo). Megrez means base of the tail. This is typical of most star names, which either describe the star, or its location in its constellation.

Of course, there are some oddities, such as a star whose name means hyena in Draco the dragon, or monkey in Columba the dove. These names are remnants of ancient constellations that have been lost, eliminated or ignored.

Some names present challenges in various ways. Libra has five named stars: Zubeneschamali, Zubenelgenubi, Zubenelgubi, Zubenhakrabi, and Mulizi. Zuben means claw in Arabic, and the rest of the names mean north, south, or just "of the crab." Mulizi snuck in from the Akkadian language of 3000 years ago, and means "man of fire." (I used to rattle those names off to my classes, and then say they would be on their next test, "spelling counts." Strictly to see who was awake.)

About a dozen stars are named for astronomers who either discovered them or did major studies of them. The eminent Dutch astronomer Jacobus Kapteyn (1851-1922) has a star in the southern constellation of Pictor, a crater on the Moon, and an asteroid named for him, an impressive celestial trifecta.

There are 88 constellations recognized by the astronomical community today, based on recommendations made about 130 years ago by Benjamin S. Gould, the first American to earn a PhD in astronomy (he got it from Heidelberg University in Germany, where they have been giving such degrees for centuries). Gould selected the 48 ancient constellations and 40 that had been invented mostly between 1500 and 1800 to fill gaps left by the ancients. 81 of these constellations have one or more stars with a name more interesting than a Greek letter or catalog number. Most of the seven with no named stars are modern, dim, southern constellations, such as Antlia and Circinus.

Around 1600 a German mapmaker, Johannes Bayer, created a map of the sky, and for no known reason attached Greek letters to many of the stars. His idea was popular, and thus we have such names as Alpha Centauri. The first Astronomer Royal, John Flamsteed had a different idea, and around 1690 started the practice of numbering stars within each constellation, going from west to east. Thus Sirius is also Alpha Canis Majoris and 8 Canis Majoris (neither of these is a particularly popular alternative). Later catalogs have introduced additional ways to designate a star, the result being that the average star has as many pseudonyms as the average hard working bank robber.

Notice that there is no mention of purchased names. These are totally ignored by the astronomy profession, and it is a source of annoyance to have people walk into a planetarium and ask to be shown a star they think they purchased. (If they bought the Brookyn Bridge it would be as meaningful.) In my many years of training students to work in the planetarium field, one of the things I have had to advise is how to handle people with negative reactions to learning they wasted their money, particularly bereaved parents who had hoped to create a lasting memorial to a deceased child.

Wednesday 21 March 2012

Neighbor Stars

There is an old trick question in astronomy, what is the nearest star? The correct answer is the Sun, unless one specifies "nearest to the Sun" or "nearest to the Solar System."

The closest star after the Sun is best known as Proxima Centauri, but masquerades under a variety of names, such as Alpha Centauri C, HIP 70890, GJ 551, and V645 Centauri. Just as we recently passed the centennial of the Titanic disaster, we are soon coming to the centennial of the discovery of Proxima Centauri. It was discovered in 1915 by the Scottish astronomer Robert T. A. Innes (1861-1933), working at the Union Observatory in South Africa, in 1915. But it was not recognized as the nearest star until 1928, when the American astronomer Harold Alden (1890-1964) made the first measurement.

Proxima Centauri is 4.243 light years from us, where a light year is 5,878,625,373,183.6 miles, a fine example of how astronomers avoided writers cramp by inventing the light year. Proxima is 270,000 times further away than the Sun is from Earth. Proxima Centauri is a very dim star, called a red dwarf. Unless one uses a telescope, it will never be visible. The dimness results from its small size (thus the dwarf part of its type), 126,000 mile diameter (14.5% of the Sun's 864,000 mile diameter) and cool temperature (red stars are the coolest). Where the normal, undisturbed temperature of the Sun's surface is around 9950 F (and possibly as low as 8100 F inside sunspots), Proxima's surface temperature is little more than 3000 F. However, in 1951 Harvard astronomer Harlow Shapley discovered Proxima has periodic flares that can increase temperatures in a limited region by a few thousand degrees. No planets have been found around this star (the first extensive search for planets is being planned by the Planetary Society), but they would have to be between 2.14 million and 5 million miles from the star for temperatures to allow water to be liquid. Of course, the flares would fry anything living that close.

With the Sun and Proxima both moving through space, we will be closest in 27,400 years, when Proxima will be only 2.90 light years away, and still too faint to see without a telescope, unless human eyesight has improved a lot by then.

Proxima Centauri is in an enormous orbit around Alpha Centauri, probably taking close to half a million years to go around once. Alpha is itself two stars. one very similar to the Sun, and one a bit smaller and cooler. The pair are among the brightest stars in the sky, but only visible from fairly far south. These two stars orbit each other in 80 years, ranging from one billion to over three billion miles apart. All three stars are believed to be around 4.85 billion years old (about 500 million years older than the Sun). Proxima, however, is expected to last for another 400 billion years, long after its companions or the Sun have burned out.

The next three closest stars are loners, like the Sun, and red dwarfs like Proxima Centauri. The first is called Barnard's Star in memory of the American astronomer Edward Emerson Barnard (1857-1923) who discovered it in 1916 while working at Lick Observatory in California. It is twice the age of the Sun, and 5.9 light years from us. There have been unsubstantiated claims of a planet going around Barnard's Star, but most astronomers think the claims are a mistake. The second is Wolf 359, so called because it is the 359th star in a list of red dwarfs drawn up by the German astronomer Maximilian Franz Josef Wolf (1863-1932). Barnard's is located in the constellation of Ophiuchus while Wolf 359 is in Leo. Third is Lalande 21185, from a catalog prepared by the French astronomer Jerome Lalande (1732-1807), located in Ursa Major. None of these stars can be seen without a telescope, and no planets are known for any of them although Lalande 21185 had an apparently erroneous claim made in1951. Wolf 359 is so small that it is only a third larger than Jupiter.

We finally come to a bright star, Sirius, 8.6 light years from us, and the brightest star in the night sky (although, strangely, some people think Polaris is the brightest, when it only ranks number 50). Sirius weighs twice what the Sun does, and is much hotter, with a surface temperature approaching 20,000 F. Hot stars have shorter life spans, and Sirius is not expected to last more than a billion years, with a couple hundred million yet to go. Sirius has a small very hot star going around it in a fifty year orbit. This companion star was the first white dwarf to be discovered, by the American telescope manufacturer Alvan Graham Clark (1832-1897), testing a new telescope in 1862. It is slightly larger than Earth, but weighs nearly as much as the Sun, 324,000 times the mass of the Earth. It is a star nearing the end of its life, having evolved faster than its companion.

The last three stars within ten light years of us are a pair of red dwarfs, Luyten 726-8, discovered in the constellation Cetus by a Dutch astronomer in 1948, and Ross 154, also a red dwarf. It is in the constellation of Sagittarius. No one has suggested any planets for these stars.

But in 2011 the WISE spacecraft found a brown dwarf in the constellation Lyra, just 9.6 light years away. With a surface temperature of 80 F, it could not warm any planet enough to support life, but no planets have been found around any brown dwarfs.

Thus within ten light years of Earth we have 12 stars (including the Sun) and one brown dwarf, with no confirmed planets except around the Sun. Most of the stars are small, cool and dim red dwarfs, leaving the Sun as one of just three larger stars. This seems to match what is found throughout our galaxy, that about three quarters of all stars are red dwarfs, six percent are white dwarfs, and only about five percent are similar in size and temperature to the Sun. But with over 200 billion stars in our galaxy, that leaves a lot that match the star we are in orbit around.

Thursday 15 March 2012

Where Is the Space Race Today?

In the 1950s and 60s the Soviet Union rolled up an impressive series of first in space, including the first satellite, the first animal in space, the first man in space, the first woman in space, the first spacewalk, the first spacecraft to orbit the Moon, the first spacecraft to land on the Moon, and the first spacecraft to land on Venus (after eight tries). Until the Gemini program, the USA was definitely lagging. The Apollo landings on the Moon seemed to end much of the competition. Both countries settled down to creating systems of communications, weather and spy satellites.

After the Soviet Union collapsed, Russia tried to continue its space efforts, but on a reduced scale. President Reagan's dream of a space station was to be transformed into the International Space Station, largely built with the use of America's Space Shuttle.

But the Space Shuttles were supposed to be good for 100 launches each, and there were supposed to be two launches per month. Neither happened. In fact, the Shuttles rolled into retirement after only 136 total launches, and most years saw no more than four launches.

So today the USA has no access to the space station it was largely responsible for building except to ride aboard a Russian Soyuz spacecraft. Even supplies are mostly taken on Russian Progres unmanned vehicles, although American firms such as SpaceX hope to get much of that business in the near future.

Meanwhile, other countries are moving into space. China, Japan, India, Israel, and the European Union have all successfully launched satellites using their own rockets. China has launched their own astronauts as well, and have tested a space station of their own design in orbit. China, India and the Europeans have placed satellites in orbit around the Moon, and Japan has visited an asteroid. China has made public plans for manned landings on the Moon, probably followed by construction of a permanent base there.

The USA claims to be designing new rockets capable of taking crews to the Moon or a nearby asteroid, but with no well-defined plans for either, and with Congress viewing the NASA budget as a prime place to take away funds. The only candidate in this year's Presidential primaries to raise the issue of space was widely ridiculed for it.

So while NASA has held a conference recently on a one hundred year plan for design and launch early in the next century of a probe to nearby stars such as Alpha Centauri and Barnard's Star, America may well find itself incapable of any activities in space, either through neglect or by unfriendly countries.

The most hopeful thought is that American space efforts have always fluctuated from neglect to emergency crash efforts, and may continue to do so. After all, in 1957 the American Secretary of Defense expressed the opinion that he was glad the Soviet Union was the first to launch a satellite, and America would in fact have been first by over a year had not some Pentagon official made sure the top stage of a test rocket in September 1956 had sand instead of rocket fuel.

So in the words of an old sci fi movie, "keep watching the skies", because there is no assurance what will happen next.

Friday 9 March 2012

The Spiritual Significance of Astronomical Events in 2012

As I write just hours after the blessing of the new moon here in the UK on 21st May 2012, somewhere else in the world our moon is being born anew.

The eclipse which accompanied the birth has been called a lunar ring of fire because that is how it appeared, and many who witnessed it, largely in Japan and parts of the US, were awed by its beauty and mystery as the moon, far, far from Earth, was overshadowed by the sun and the two celestial beings which are so influential on Earth walked together.

Annular eclipses occur regularly but this one was special, coming as it did exactly between the two great spiritual festivals of Wesak two weeks ago and that of the Christ, at the full moon to come. You can see how perfectly the moon's cycle correlates with events in the story of man as you look at the ring of fire around you - indeed, "firewalls" are being attempted everywhere to stop the unravelling of life as we have known it, but they will not stop the powerful combination of sun and moon together moving us forward to where we have chosen to go.

Rather than fighting the ring of fire, accept and embrace it as a gift from Spirit. For me, today, I take the fiery ring of sun and moon and place myself within it, choosing to be a part of it and not excluded from it. What better firewall can there be than the fire itself?

The implications of the transit of Venus on 6th June 2012 across the face of the Sun are much more significant for Planet Earth than is generally understood, and very important, for they are all about the acceleration of your spiritual journey and the completion of the Plan of God.

Venus, like Sirius, is a staging post for certain enlightened souls which return to Earth for a new human incarnation: just as some individuals are put through an intensive pre-training process before undertaking a new job, so too you may have spent time on the Rose Planet, learning about what love means before entering the heavy and self-centred world of matter. So, there is a connection with Earth already, but this Venus transit, more than any other so far, is taking the link to another level as its breath upon Earth enables the releasing of new spiritual energy and signals a change in the role of all the planets in our solar system, particularly ours, the Blue Planet.

Just as millions of us watched the Queen, the personification of the gift of constant giving, light the national beacon 24 hours earlier, so God, through Venus, has set fire to the touch-paper which leads to a new phase, a new future for us all, everywhere. You are being released to claim your human and planetary birthright, written in the stars in every sense, whereby our planet and your soul become the cosmic centre of communication and training based on the deepest aspects of love, in time replacing Venus in a startling reversal and enhancement of role.

Remember this as you see pictures of this transit of Venus, the dark circle highlighted upon the solar sea of fire which is, in truth, God's fingerprint. We have been blessed.

Saturday 3 March 2012

Useful Accessories for An Amateur Astronomer

You've got a telescope and a choice of eyepieces, so what extras can make your watching hours more pleasant as well as effective? Listed here is a number of several very helpful add-ons in order to take your star gazing to the next step

You've devoted around 30 minutes getting your eyesight modified to the dark, you believe you can view a weak star cluster and consequently take advice from your star chart to ascertain if you're right. You start up your torch in order to look over the guide and within a moment you lose your night vision. You may have to wait patiently to acclimatize your eyes again. The simple answer is to acquire a red-colored light flashlight. An effective way to accomplish this is usually to place reddish colored finger nail polish upon an aged flashlight you don't want to have or you can acquire these easily.

A good Barlow lens often comes in twice as well as three times zoom. You place the Barlow lens in the standard position for your main eyepieces on your own telescope and then insert your own eyepiece directly into the Barlow lens. The main reason they can indeed be so handy is that you automatically multiply by two the number of eyepiece zoom you own, as every eyepiece is now able to provide you 2 distinct magnifications. On top of that, reduced strength eyepieces usually are a lot easier to gaze through because the lens is bigger and therefore the space your eyeball should be from the lens is far more pleasant (termed eye relief) thus a Barlow lens permits you to see increased zoom a lot more pleasantly also.

Just like a Barlow lens aids in zoom a very good wide-field eyepiece lets you discover more of the night time sky through the eyepiece. This allows you to identify objects quicker and revel in quite a few constellations.

There are a number of star chart software out there pertaining to smartphones on the market. The Distant Suns software on the Apple iPhone comes strongly recommended. It'll show you specifically what is up in the night time sky for you at the current time, focus in to just about any star, constellation or even deep space target. It's also possible to direct it at the night sky and it'll clarify what you are staring at.

Filters go with your eyepiece and alter the light entering your view. Quite possibly the most valuable one is without a doubt a lunar filter which will take the glare away from observing the moon and additionally offers contrast to your observation. Color filters can easily enhance the observation of the planets and a light pollution filter is built to minimize the orange colored illumination as a result of suburban lighting. These can boost the contrast between a faint deep space target and the night sky. Having said that the improvement doesn't seem to be fantastic.

Monday 27 February 2012

Types of Astronomy Observatory Domes

When making an astronomy observatory, it is essential to consider many factors like the location, size, forecasts, budget and equipment. One very important point to note is that the equipment needs to be protected from the elements and also from animals or trespassing people. Yet at the same time the protection should not be rigid to prevent the telescope from moving or changing angles. The best solution for this is the Astronomy Observatory domes. They help in preventing light diffusion along with protection.

The modern astronomy observatory domes are lightweight, easy to install, easy to clean and of various sizes and colors. The observatory dome does not need to be a hemisphere, its function is to protect the equipment and that can be done even if it is not a semi-circle. There are many classes of domes based on their shape. Pyramidal class of domes consists of all faceted structures and is the most simple and easy to construct, they consist of conical or drum shaped domes too. The conical or drum shaped domes have the problem of providing the slit at the peak which is required to enable the astronomer to see right above the head. There is another problem of providing shutters to such slits.

There are many cases of astronomy observatory domes where the shutters are made with over-lapping joints. In many cases a single shutter might not be enough and multiple shutters are used. Flexible shutters are also used to cover the slit in some cases, but then it might be strong enough to withstand strong winds, hail storms, ice, and heavy rain.

The next class of astronomy observatory domes is the pseudo-hemisphere domes, these use flat planes and also single plane curved panels. The main and most commonly used is the hemisphere class of domes. These are the most aesthetically appealing type of dome. A point to note is that more the number of edges and corners, more the chance of constructional problems like leakage and breakage. One important aspect of all astronomy observatory domes is the ability of the dome to move freely and ideally 360 degrees. They should also have an opening which can comfortably accommodate the telescope at any angle allowing the astronomer to view the skies in any direction or in any angle. At the same time the opening should have the capacity to shut with a shutter to prevent direct exposure of the equipment to the wind, rain and sun.

The most critical and difficult part to design is the shutter. Fabricating a shutter is not an easy task. The pseudo-hemisphere style will have to be fabricated from trapezoidal plates while the hemisphere style has just two panels which curve in two directions thus forming a uniform curve. Making such uniform curvature is more difficult than making a straight faceted panel. In case of pseudo-hemisphere many trapezoidal plates are joined together to give faceted kind of look to the dome. Astronomy Observatory domes are the main stay of any observatories, might it be a backyard observatory or a school or institutional observatory. The observatory domes are usually hemispherical in case of the ready-made astronomy observatories available in the market. Whatever is the color or the shape of the astronomy observatory dome, its main job is to give protection to the equipments from the elements.

Tuesday 21 February 2012

Backyard Observatories - Location Is an Important Point to Be Considered

Every night when the stars are out, one always wonders how they look from close and what stories they have to tell. The beautiful night sky with bright stars and the planets in different shapes and colors are an intriguing picture for many especially children. The dreams of astronomy starts young and many take steps towards their dream by building backyard observatories.

Backyard observatories are not very difficult to construct if proper instructions and precautions are followed. There are lots of options in making backyard observatories. It is possible to buy ready-made kit of the complete infrastructure required or it can be done by the person itself. There are lots of documents and books available providing guidelines for construction of the observatories. The minimum area required, the location, the types of roofs, the construction material required, the type of telescopes, the precautions are all dealt with in "Make it yourself" books or documents. The first main step to make a backyard observatory is the location. It is the most vital decision that needs to be taken.

Astronomers forecast are an important aspect for viewing the skies, it is important to know if the skies are cloudy or clear. There are weather forecasts, especially developed models of numerical weather forecasts which are accurate. The forecasts cover, cloud cover, transparency, seeing ability meaning the ability to magnify finer details at a particular time. The darkness level of the night sky varying from black to dark blue to diffused lights is also important. The wind speed at the tree-top level is also considered. Humidity levels are also important. The general temperature is also kept in mind, to help the person wear suitable clothing while star-gazing.

One important thing to note while building backyard observatories is the location. It definitely needs to be an area where the clear night sky will be seen. The sky conditions vary from slightly polluted suburban localities to clear small rural areas. The area should not be wooded which would obstruct the view of the telescope. The skies should be clearly visible, without being polluted by city lights or even building lights; the clarity of observation will not be good, if there are diffused lights while viewing through the telescope.

The reasoning behind this is that to see any object through the telescope there should be a difference in the background and the object being observed. If the background has diffused light and the object is also faint, then the chance of seeing minute details are less. The contrast between the background and the object is the most important. If the object itself is very bright on its own, like the moon, then there is no problem even if the background is light diffused.

The other factors are also important while choosing a location for building a backyard observatory. The Humidity of the area, the turbulence of cloud cover usually seen in the area, the transparency seen in the area are all important while deciding on a location. The tree cover and the height of the surrounding buildings are important because this can obstruct view of some parts of the sky. Thus the first step of choice of location for building a backyard observatory is an important one to be considered carefully and wisely.