International Year of Astronomy - Astronomy Today

In the May issue of Sky Notes I reviewed some of the changes that have taken place in astronomy during my fifty odd years as an observer of the heavens. The title included a gentle pun - Astronomy now and then. I did not point this out at the time but having moved from a glorious summer (here in the Northern Isles at least) to a dull, wet autumn, I think I should say that my intention was to imply that practical astronomy is indeed an on and off affair, dictated by the weather.

One requires a great store of patience. And so when occasionally I am accused of being short tempered I gently point out that most of my reserves have been used up dealing with the frustrations that inevitably follow when one takes up astronomy.

Since the May issue was not archived (and this one should be) then I give the text again at the bottom of this article.

This International Year of Astronomy was chosen the celebrate Galileo’s pioneering work with a small optical telescope just four hundred years ago.

In order to capture something of the excitement that must have driven Galileo one should approach observing in the spirit of the great man himself. First, use the eye unaided to observe the sky, then move to optical assistance in graded, small steps. Only by this means can we form some sense of perspective and achievement.

As I said back in May, today it is possible to purchase a highly sophisticated piece of equipment and to point it to almost anything you desire without having a clue as to how it is done. I am not referring to the computer circuitry but to the fundamentals of what we classicists call spherical astronomy.

At the age of fifteen I had decided I wanted to follow astronomy as a profession. The advice I received from my elders was unanimous – you need to be exceptional at mathematics to do that! Having little money in those days I decided the only contribution I could make to the subject at that time would be done without a telescope – that might come later. And so I set about teaching myself the rudiments of mathematical astronomy; and then, that same year, I joined the British Astronomical Association and began work with the Computing Section, to which I still contribute incidentally.

There were no computers then as we understand them today – the word “compute” referred to the process of mathematically solving astronomical tasks: the production of tables listing forthcoming events and so forth. To work an ephemeris for a comet, for example, would have taken several weeks using six-figure mathematical tables, a task that a modern computer might achieve in minutes.

My progression towards using large telescopes was relatively slow but it was thorough. I do not regret my long apprenticeship for even now I find I can still “outwit” a piece of modern technology when pushed!

Advances in theoretical astronomy have evolved alongside the ever-increasing complexity in instrumentation. The astronomer’s “antennae” now permit us to observe well outside the range of the visible spectrum. (The average human eye is sensitive between 4,000 and 7,000 Angstroms – crudely, blue to red.) In consequence our understanding of the physics, chemistry and dynamics of outer space has had to be revised and revised, again and again.

Interpreting the results of observation tax the human mind to the full. Our natural inquisitiveness is never fulfilled, that is a basic human trait. We now think we understand how things “work” out there far more reliably than we did a century ago. Few would challenge this validity in most areas of modern astrophysics. But astrophysics has broadened enormously in its scope.

As a mathematician of limited means I have constantly to remind myself that this tool has its limitations too. One has to bear in mind that mathematics, along with other similar systems, is of our own devising. We are part of the physical environment not lords over it. We attempt to make sense and order from the functioning of the natural world of which we are part. In this we define and manipulate. Concepts are formed which account to us both the physical and the non-physical. But nothing is straightforward and the more we look into a problem the more complex it becomes. One has only to follow the course of atomic physics to understand what I am saying on this point.

I read from the notebook I kept in those early days that my first recorded observation was of Saturn on May 4th 1951. This was made with a 20 x 60 mm Watson terrestrial telescope mounted on an improvised stand constructed from Meccano. I came across the planet when sweeping the sky: I sat transfixed hardly able to believe my eyes. The image was very small but the rings were there right enough, just as they were depicted in all the books I had read.

Saturn was then in the constellation Virgo in almost the same position it occupies during 2009/2010. Thus Saturn has made exactly two revolutions of the sky during my time as an observer.

As I have stressed many times, the conditions for the observer at the Earth’s surface have deteriorated markedly over the past fifty years. In the looming energy crisis people often talk of the gloom scenario where the “lights go out”. (Many an astronomer, including myself, would welcome that!) But lighting today using LED technology is comparatively cheap and so I fear we may freeze (or fry?) before we have to forgo twenty-four hour illuminations.

Yesterday they “dropped” two projectiles close to the Moon’s south pole in a search for water. And so I shall end this brief summary with a short poem one of many such efforts I have made in my “parallel career” as a writer:

No rival

There was a time,
not so long ago,
when the moon at night,
reflected in a mill pond,
had no rival.

JV 15/10/09

International Year of Astronomy - Astronomy now and then.

This may be a good opportunity to compare briefly the state of amateur astronomy now to how it was when I started out some sixty years back.

The first thing to say is that the range of equipment today is far and away more advanced than anything we had back in the fifties. Today even a basic refracting telescope of good quality may be purchased for a fraction of the cost (in real terms) and there is a far greater selection from which to choose. Much larger apertures may be achieved, as they always have, by the use of reflecting telescopes. There have been great improvements here too: the Cassegrain system is less unwieldy and more durable that the open tube Newtonians. A Maksotov-Cassegrain is a good compromise for those lacking the resources for an equivalent size in refracting telescopes, and it too is a good deal more compact.

But the most significant advance has come from the developments in digital technology providing observers with the means of securing images of astronomical subjects unimaginable fifty years ago. Not only that, but everything has been speeded up – you can view your images as they are being gathered whereas film takes hours to process.

Telescope mountings too have been made more accessible in terms of cost and size. The equatorial head alone for my 5.2 inch Cooke (Fig.1) weighs over 60 kg – nearer 80 kg with counterweights. By contrast the shorter focal length (smaller “f” ratios) in the case of modern refractors means that a comparable aperture may be mounted on a portable assembly such as that shown in Fig. 2. However, a word of caution is necessary for those contemplating a larger telescope working outside in such places as the Northern Isles. In general fork mounts fitted with equatorial wedge plates are too unstable for serious work at high powers when exposed to anything more than a gentle breeze. [At the time of writing this article a force 10 gale is raging in the Westray Firth and here, on this sheltered east side of Rousay, I am reduced to a small 80mm refractor for observing Venus.

On the other hand, one advantage for most observers offered by these modern mounts is the addition of so-called “goto” software. Even the process of polar alignment has been simplified so that for the most part one does not have to understand the basic principles involved. And once set up all one has to do is master the handset, press a few buttons in order to access an object from a database.

And astronomy today (magazine publishers please note) is far better served by the media in general than it was in my youth.

As a result of these “improvements” observers may undertake more advanced work – much of it digitally recorded and stored. But for me there are two questions that need to be answered. First, have modern techniques increased the observers understanding and pleasure? Second, has the visual observer’s contribution been downgraded?

There is a third and more fundamental question at the core to all this: what is it all for – what use can it fulfil? There is no short answer to that. We may think of ourselves as adding to the fund of scientific knowledge when we discover a new comet, an asteroid, a nova or what have you; certainly we are helping to expand the databases. In fact so vast is the assemblage of recorded “fact” that we have had to hand over its analysis to the computer itself. In a nutshell (a Hawkinsian concept?) the practice of astronomy has lead us into realms of conjecture and hypothesis only intelligible to a relatively small number of specialists.

I take the view that unless our science leads us to make humane choices in the use to which our knowledge is put we might be better off without it. Our ability to tap into nuclear processes has led the world into a perilous condition - that cannot be denied.

Leaving aside all the changes in technology how does the more casual observer of the sky fare today compared to sixty or so years back? When in 1948 we moved into the Essex countryside from a London suburb the skies were dark at night and unsullied by aircraft condensation trails by day or night. When I left the same area in 1960 the night sky was an orange glow from sodium lighting and civil aircraft plied their way contributing to the formation of high cirrus cloud.

Much the same pattern has followed worldwide and Orkney offers no more the pristine, clear skies it did back in the seventies and early eighties. From my home on Rousay there are literally hundreds of lights visible on the other islands and from the sea – no longer is the Milky Way visible from horizon to horizon on a clear night. And in the near sky, artificial Earth satellites are in abundance turning constellations into contorted depictions of themselves.

Things have changed. For good or bad depends upon your perspective. The main thing IS to enjoy what is still a minority pursuit and to pass on one’s enthusiasms as best we can, often under challenging circumstances.

JV 05/05/09