Such a routine carried on with iron inflexibility was exceedingly trying, as it was absolutely impossible for an observer to keep any regularity in his hours of rest or times for meals.
This routine has been considerably modified by the present Astronomer Royal, partly because the instruments now in regular daily use are five instead of two, and partly because a less stringent system has proved not merely far less wearing to the observers, but also much more prolific of results. It was impossible for a man to be at his best for long under the old régime, and from forty-six to forty-seven has been an ordinary age for an assistant to break down under the strain.
One point in which the observing work has been lightened has been in the discontinuance of the altazimuth observations at the full of the moon, another in the shortening of the hours of the transit circle watch; and a further and most important one in the arrangement that the observers with the larger instruments should have help at their work. The net result of these changes has been a most striking increase in the amount of work achieved. Thus, whilst in the year ending May 20, 1875, 3780 transits were taken with the transit circle, and 3636 determinations of north polar distance; in that ending May 10, 1895, the numbers had risen to 11,240 and 11,006 respectively, the telescope remaining precisely the same.
One principle of Airy's rule still remains. So far as possible no observer is on duty for two consecutive days, but a long day of desk work and observing is followed by a short day of desk work without observing.
It will be readily understood that with five principal telescopes in constant work and one or two minor ones, some demanding two observers, others only one, each telescope having its special programme and its special hours of work, whilst by no means every member of the staff is authorized to observe with all instruments indifferently, it becomes a somewhat intricate matter to arrange the weekly rota in strict accordance with the foregoing principle, and with the further one, that whilst a considerable amount of Sunday observing is inevitable, the average duty of an observer should be three days a week, not seven days a fortnight. There is a story, received with much reserve at Cambridge, that there was once a man at that university who had mastered all the colours and combinations of shades and colours of the various colleges and clubs. If so gifted a being ever existed, he may be paralleled by the Greenwich assistant who can predict for any future epoch the sequence of duties throughout the entire establishment. At any rate, one of the first items in the week's programme is the preparation of the rota for the week, or rather, to use an ecclesiastical term, for the 'octave,' i.e. from the Monday to the Monday following.
The special work to be carried out on any telescope is likewise a matter of programme. For the transit circle a list of the most important objects to be observed is supplied for the observer's use, and the general lines upon which the other stars are to be selected from a huge 'Working Catalogue' are well understood. With some of the other telescopes the principles upon which the objects are to be selected are laid down, but the actual choice is left to the discretion of the observer at the time. There is no time for the watcher to spend in what the outsider would regard as 'discovery'; such as sweeping for comets or asteroids, hunting for variable stars, sketching planets, and so forth. Indeed, there is a story current in the Observatory that some fifty years ago, when the tide of asteroid discovery first set in, Airy found an assistant, since famous, working with a telescope on his 'off-duty' night. That stern disciplinarian asked what business the assistant had to be there on his free night, and on being told he was 'searching for new planets,' he was severely reprimanded and ordered to discontinue at once. A similar energy would not meet so gruff a discouragement to-day; but the routine work so fully occupies both staff and telescopes that an assistant may be most thoroughly devoted to his science, and yet pass a decade at the Observatory without ever seeing those 'show places' of the sky which an amateur would have run over in the first week after receiving his telescope. For example, there is no refractor in the British Isles so competent to bring out the vivid green light of the great Orion nebula—that marvellous mass of glowing, curdling, emerald cloud—or the indescribable magnificence of the myriad suns that cluster like swarming bees or the grapes of Eshcol in the constellation of Hercules; yet probably most of the staff have never seen either spectacle through it. The professional astronomer who is worth his salt will find abundance of charm and interest in his work, but he will not,
'Like a girl,
Valuing the giddy pleasures of the eyes,'
consider the charm to lie mainly in the occasional sight of wonderful beauty which his work may bring to him, nor the interest in some chance phenomenon which may make his name known.
It is not every field of astronomy that is cultivated at Greenwich. The search for comets and for 'pocket planets' forms no part of its programme; and the occupation so fascinating to those who take it up, of drawing the details on the surfaces of the moon, Mars, Jupiter, or Saturn, has been but little followed. Such work is here incidental, not fundamental, and the same may be said of certain spectroscopic observations of new or variable stars, and of many similar subjects. Work such as this is most interesting to the general public, and is followed with much devotion by many amateur astronomers. For that very reason it does not form an integral part of the programme of our State observatory. But work which is necessary for the general good, or for the advancement of the science, and which demands observations carried on continuously for many years, and strict unity of instruments and methods, cannot possibly be left to chance individual zeal, and is therefore rightly made the first object at Greenwich.