THERE is an apocryphal tale told to young designers about the dangers of rigid thinking, which concerns the early years of NASA's space programme.

One of the APOLLO rockets, so the story goes, was made 6" taller than the earlier craft. When the time came to transport it from the construction site to the launch pad, the team hit an unforeseen problem. The rocket, which for technical reasons had to be transported vertically, was a couple of inches too tall to pass under the bridges which lay along the route.

A quick calculation showed that even partial destruction and rebuilding of the bridges would cost millions of dollars. The only other option they seemed to have, taking the rocket apart and re-assembling it at the launch site would cost at least as much.

A lot of intelligent people began to feel rather stupid. In a last ditch attempt to avoid incurring the kind of expenses which do nobodies career much good. The project called in a consultant who did not pretend to be an expert on space flight or on bridges . . . .

He did however, have an uncanny ability to solve problems. Within minutes, this man hit upon a solution which cost not a cent.

He suggested they deflate the tyres of the transporter every time it had to go under one of the bridges. as soon as the rocket was safely through, the tyres could be reinflated.

Obvious? Maybe, but for most people only in retrospect.

STEVE PAYNE

THE following notes may be of interest to members, not only to those who are beginners in finding their way around the night sky, but also those who are a little more experienced.

Once basic star and constellation recognition skills have been established it will now be possible to apply ones time in a slightly more serious manner; namely naked eye variable star observing.

I've prepared two charts to start you off, of the well known constellations, Cassiopeia and Gemini. The object of the exercise is to estimate the magnitude of a variable against the stars listed whose magnitudes are stable and accurately calibrated and not too dissimilar to the total range of amplitude of the variable being studied.

For example, if you consider g Cass. the variable star in Cassiopeia to be equal to b Cass., write down 2.2. However if you feel g is slightly fainter than b but may be a little brighter than 6 Cass. write down your magnitude estimation as 2.4 as this is half way between 6 and b in brightness along with the date and time and perhaps the quality of the seeing which might be judged by noting the faintest star magnitude visible overhead. And its as straight forward as that...

Of cause the above notes are aimed at the very beginner who wishes to make a start in variable star observing. For the more demanding and serious study of variable stars a little more time and attention to detailed will be needed and of course access to a telescope, which could put off the beginner variable star student, so I've purposely kept the procedure of studying g Cass. and h Gemini very simple.

g Cassiopeia is a peculiar variable star normally the 3rd brightest in Cassiopeia, regarded as a young star of around 9 million years old.

Because its a young star newly formed, we know from its spectrum that the star is rotating at a very high speed, as a result of this, along with other unknown reasons the star expels its outer atmosphere. Now until 1936 it had shone steadily as a 3.0 mag. star, but early in that year it suddenly and unexpectedly started to brighten, this continued until May 1937 by which time it was of magnitude 1.4 making it slightly brighter than b Cass., and deepening in colour to an abnormal yellow tint. Although a brightening of 1.5 magnitudes is not that unusual for a star, but when it happens to a 3rd mag. star, that star becomes one of the brightest stars in the entire sky.

During the later months of 1937 it faded rapidly with fluctuations of decreasing amplitude and by 1940 it had sunk to a lower level than from which it had started (about 2.8); here, more or less consistently remained. My own observations show a steady magnitude of 2.2 over the last few years. Very accurate measures have however shown that faint and quasi periodic variations still persist and there is no reason to suppose that its more spectacular performance may not one day be repeated.

A large number of spectroscopic observations were made during its outburst and these indicate that the star expelled its outer atmosphere and photospheric layers; ultimately this envelope became entirely detached from the star.

In 1965 g Cass again showed signs of brightening but not to the same degree as occurred in the late 1930's

Frequency of Observation and Comparison Stars to use.

Due to the very slow change in the magnitude g needs to be kept under careful scrutiny and as such its on the BAA variable star priority list. The frequency of the number of times you make a estimate of its brightness, some authorities suggest once or twice a week, but I find this far too frequent for my observing practice and so I limit it to only once or twice per month.

Suggested comparison stars;
a And. 2.07
e Cyg 2.46
g ±Cygni 2.22
a Pegasi 2.48
b U. Major 2.35

Before leaving Cassiopeia the following may be of interest.

r Rho Cassiopeia, this star can be seen with the unaided eye on any clear night, however r was discovered to be variable by Miss Wells, an American lady working, I believe, at a professional observatory in1901.

r Cass. a super giant star with a diameter of 600,000,000 miles, of intermediate spectral type. Usually of 4.4 mag. and known to fade on very rare occasions to a 6.2 minima, the last known fade was during 1945 to 1947. As its so faint for effective naked eye observations, binoculars are required for a proper study of it.

Comparison stars to use are;
c Cass 4.2
q Cass 4.5
l Cass 4.8
s Cass 4.9
g Cass 5.1

For positions of the comparison stars may I suggest you refer to Norton's star atlas for their positions in the sky.

r Cassiopeia is also on the priority list of the BAA variable star section and so worth monitoring. At one time a Cass. was considered to be variable with a range of 2.2 to 2.8, but no definite period. The discovery was made by W.R. Birt - (presume-able the same Birt, an English selenographer) in 1831. However professional astronomers consider the alleged variability of a Cass. is almost wholly attributable to errors of observation. But could a be a star that varies at very infrequent intervals and with long periods of inactivity?

h Geminorum was discovered by Julius Schmidt during the last century along with many others he discovered during his long active observing life. h Gem. is a semi-regular star with a range of 3.2 to 3.9, with a period of 233 days, so quite suitable for naked eye observation with a frequency of once every 7 to 10 days. Over the long term if you are persistent enough you will notice a different pattern of variation both with amplitude and periodicity on each successive cycle as the years go by.

Comparison stars to use are;
m Gem. 2.8 (slight var.)
e Gem. 2.9
d Tau. 3.0
x Gem. 3.3
l Gem. 3.6
u Gem. 4.1
11 Gem. 4.1

If any of the above is attempted, you will have gained some first hand experience of variable star observing and also improve your knowledge; like knowing the names and positions of the comparison stars listed, which otherwise you would never probably bother in getting to know.

GO OUTSIDE on a clear night and look at the sky. What you see is not necessary what actually is there, what you are seeing is mixed in your minds eye with all of the knowledge of the late 20th century's science of astronomy along with all of the wonderfully images beamed to us from distant space craft or the Hubble Space Telescope's new sharp views of the heavens.

You can't help it, you know what you're seeing when you look at a star, a misty patch of light of a distant galaxy or a nearby planet. Turn your telescope on to the Moon and you can see the dust, the rocks, the craters, or look at the mare; flooded, not with water, but with long solidified lavas. You know because we've been there and everyone has seen the films of the 12 astronauts bouncing around on our twin world we call the Moon.

We have all read in books and magazines what the worlds of the Moon and the planets are like. Mercury, moon like, roasted by the sun on one side and freezing on the other. Venus, Hell? Mars, no Martians, just craters and dust with a little frozen water at the poles. Jupiter, nearly got to be a small star and would have had its very own solar system with its large and small moons. Saturn, best looker in the system?

Going outward, the stars form not just groups of patterns of the ancient gods and goddess's, but complex systems of binary and triple systems, of clouds of gravitational linked suns rotating along with us around the rim of our Milky Way galaxy. The stars to us, are dynamic objects: we understand how they burn, how long they live and how they are born and die.

Most of this knowledge has been gathered recently in the course of the last 300 years and most of all in the last 30 years as spacecraft have explored the planets and telescopes both on the ground and in orbit have looked at all the wavelengths in the electromagnetic spectrum. 30 years is a very short time in which a whole new universe has been created in the minds of men. Of cause is was there all along just waiting to be discovered, but it took a lot of work and explaining for us to be able to understand it. And it's most likely we have still got some things wrong.

But can we see the sky as the people 1000's of years ago did? Yes, find a dark spot away from lights and just look up. Clear your mind of what you know and look. To the folk of long ago the stars brought order to there lives. They where there every night and with each year repeated their movements night after night. Some nights they would see a meteor or two flash across the sky or see a comet move from night to night across the star patterns. But overall they knew the stars stayed still in the heavens.

With each season the same star patterns repeated themselves. This predictability helped to organise the year, the time for planting and the time for harvest. All over the world our ancestors built devices to measure the passing of time, at Stonehenge in England; Abu Simbel in Egypt; Chichén Itzá in Mexico; Angkor Wat in Cambodia; Chaco Canyon in New Mexico. Some of these were sophisticated sundials to measure the longest day and the shortest, some of them could predict the eclipses of the Sun and Moon.

It was obvious to the superstitious that the stars along with the Sun and the Moon controlled man. Early on in the history of astronomy the visible stars were given names as an aid to remembering and they were grouped into constellations. Old stories and legends formed the base to the names in each country along with the 12 zodiac constellations through which the Sun and the Moon moved along with the five strange bright stars.

All the stars in the sky stay in place, that is except for the five points of light that don't. Could you spot the point of light which moves a little every night while all the rest stay still? I don't think I would for a long while. Could you work out if the Sun went round the Earth or the Earth went round the Sun? After all you can't feel any movement can you? And what about working out when is the longest day and the shortest, (easy with a fixed pole and some stones to mark the suns shadow). But what about predicting an eclipse of the Sun or Moon without my computer? Phew. . .

By following the motion across the sky for a few months of one of these strange wandering or vagabond stars called planets, they would see it move from constellation to constellation and occasionally do a strange slow loop-the-loop in the sky. Also they varied in brightness slightly, dimmest near dawn and sunset and brightest when high in the sky at midnight.

As the Earth was the centre of their universe, all of the sky revolved around it. First was the Moon then Mercury and Venus followed by the Sun in their transparent spheres; then the three outer planets until you came to the last sphere of stars. Simple. All the orbits of the planets where perfect circles claimed Pythagoras in the 6th century BC. No one thought otherwise for nearly 2000 years!

However, even the Egyptians knew that Mars could travel backwards and the name they gave it meant "who travels backwards". In each of the outer spheres it was reasoned, was another smaller planet sphere called an epicycle so that the planet could turn independently. For Ptolemy this solved the problem of the retrograde motion of the planets, and for 1500 years no one tried to change it!

But what were the planets? If you look at them they look like bright stars, just points of light. Mars does look a pink colour and Jupiter creamy, while brilliant Venus is a diamond in the sky. The stars also have colours, red Betelgeuse, blue Rigel, yellow Capella. On most evenings the stars twinkle and shake slightly while the planets seem to stay still. Why? Was it possible that the planets had a solid form? When Venus is near Earth in the morning or evening sky it is seen as a crescent with a diameter of up to 62 seconds of arc. Is it possible to see its thin crescent shape like a new Moon but 30 times smaller in the twilight sky? Venus is the only planet that it may be possible for the unaided human eye to see as a shape.

The other planets have an even smaller angular diameter, which is below the resolution of the human eye see unaided. How else could they be detected as having a form? Well if, say, Jupiter or Saturn, both of which have an opposition diameter of over 40" were to pass behind a distant building, pole or rock when near opposition it would not suddenly blink out as would a star in similar circumstances but would quickly fade, within about 1 second, as it disappeared. On reappearance it would fade up in a similar amount of time. None of the stars in the sky do this, on meeting an eclipsing object they wink out in an instance as befits a distant point light source. Did the ancient astronomers of Babylonia, Egypt or Greece know this? In almost all cases they seemed to think of these bodies as something special. Something which could effect the lives of men. The planet Jupiter was thought to be the King of the planets, how did they know it was the largest planet? Venus and Mars complemented each other being the Goddess of Love and the God of War.

Then in the 16th century, Tycho Brahe spent 25 years plotting as accurately as possible without telescopic help, the positions of the stars and planets. This work helped Kepler prove that Copernicus was right about the Sun being at the centre of the Solar System, but wrong about the orbits of the planets being circles. Kepler believed that the planets had solid bodies and he seems to have been one of the first since antiquity to propose they were made of stuff like the Earth. The orbits of the planets were shown to be ellipses, moving fastest when nearest the Sun and slower when furthest away. It took another 66 years before Isaac Newton published his theory of gravitation and explained why the planets moved in such paths.

In 1610 Galileo Galilei looked through his new telescope at Jupiter and saw that it was a body with 4 stars near it. From night to night he observed them with his blurred 15x telescope. He drew in his notebook the movements of the four moons showing them changing position as they orbited the planet. He was less surprised by the planet having a body than he was at seeing that other moons could orbit a planet other than Earth. This proved that the Earth could not be the centre of all orbital movement and showed that the Copernicus system with the Sun at the centre was correct.

Later that year Galileo looked at Saturn and was surprised with what he thought he was seeing: a triple planet or one with two very large moons. When he next looked a year later, they had gone! The rings had closed up and so his primitive telescope could not resolve them. He found this very disturbing, but a year later the planet's triple nature was visible again. It was nearly 50 years later before Christiaan Huygens had a good enough telescope to be able to see the rings clearly.

Today we have a fairly good idea of what the solar system is like, but to the people of yesterday it was all a wondrous mystery unlikely ever to be resolved. If some of the old philosophers came back today, and looked at our present state-of-the-art telescopes, what would they make of it? It would astound them I'm sure, would it increase their fascination of the heavens?

You can bet it would.