The Royal Observatory, Greenwich: A Glance at Its History and Work

The Royal Observatory, Greenwich: A Glance at Its History and Work

Author:
E. Walter Maunder
Author:
E. Walter Maunder
Format:
epub
language:
English

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Author: Maunder, E. Walter (Edward Walter), 1851-1928
Astronomy — History
Royal Observatory
Greenwich
The Royal Observatory, Greenwich: A Glance at Its History and Work

E. WALTER MAUNDER, F.R.A.S.

WITH MANY PORTRAITS AND ILLUSTRATIONS FROM
OLD PRINTS AND ORIGINAL PHOTOGRAPHS

 

 

LONDON

THE RELIGIOUS TRACT SOCIETY

56 Paternoster Row, and 65 St. Paul’s Churchyard
1900


LONDON:
PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,
STAMFORD STREET AND CHARING CROSS.


PREFACE

I was present on one occasion at a popular lecture delivered in Greenwich, when the lecturer referred to the way in which so many English people travel to the ends of the earth in order to see interesting or wonderful places, and yet entirely neglect places of at least equal importance in their own land. ‘Ten minutes’ walk from this hall,’ he said, ‘is Greenwich Observatory, the most famous observatory in the world. Most of you see it every day of your lives, and yet I dare say that not one in a hundred of you has ever been inside.’

Whether the lecturer was justified in the general scope of his stricture or not, the particular instance he selected was certainly unfortunate. It was not the fault of the majority of his audience that they had not entered Greenwich Observatory, since the regulations by which it is governed forbade them doing so. These rules are none too stringent, for the efficiency of the institution would certainly suffer if it were made a ‘show’ place, like a picture gallery or museum. The work carried on therein is too continuous and important to allow of interruption by daily streams of sightseers.

To those who may at some time or other visit the Observatory it may be of interest to have at hand a short account of its history, principal instruments, and work. To the far greater number who will never be able to enter it, but who yet feel an interest in it, I would trust that this little book may prove some sort of a substitute for a personal visit.

I would wish to take this opportunity of thanking the Astronomer Royal for his kind permission to reproduce some of the astronomical photographs taken at the Observatory and to photograph the domes and instruments. I would also express my thanks to Miss Airy, for permission to reproduce the photograph of Sir G. B. Airy; to Mr. J. Nevil Maskelyne, F.R.A.S., for the portrait of Dr. Maskelyne; to Mr. Bowyer, for procuring the portraits of Bliss and Pond; to Messrs. Edney and Lacey, for many photographs of the Royal Observatory; and to the Editor of Engineering, for permission to copy two engravings of the Astrographic telescope.

E. W. M.

Royal Observatory, Greenwich,
     August, 1900.


THE NEW BUILDING.
(From a photograph by Mr. Lacey.)


CONTENTS

CHAPTER PAGE
I. Introduction 13
II. Flamsteed 25
III. Halley and his Successors 60
IV. Airy 102
V. The Observatory Buildings 124
VI. The Time Department 146
VII. The Transit and Circle Departments 181
VIII. The Altazimuth Department 205
IX. The Magnetic and Meteorological Departments 228
X. The Heliographic Department 251
XI. The Spectroscopic Department 266
XII. The Astrographic Department 284
XIII. The Double-Star Department 303
  Index 317

LIST OF ILLUSTRATIONS

  PAGE
Flamsteed, the First Astronomer Royal Frontispiece
The New Building 7
General View of the Observatory Buildings from the New Dome 12
Flamsteed’s Sextant 36
The Royal Observatory in Flamsteed’s Time 44
The ‘Camera Stellata’ in Flamsteed’s Time 52
Edmund Halley 61
Halley’s Quadrant 69
James Bradley 72
Graham’s Zenith Sector 77
Nathaniel Bliss 83
Nevil Maskelyne 87
Hadley’s Quadrant 91
John Pond 96
George Biddell Airy, Astronomer Royal 103
The Astronomer Royal’s Room 110
The South-east Tower 115
W. H. M. Christie, Astronomer Royal 121
The Astronomer Royal’s House 127
The Courtyard 130
Plan of Observatory at Present Time 134
The Great Clock and Porter’s Lodge 147
The Chronograph 158
The Time-desk 164
Harrison’s Chronometer 165
The Chronometer Room 167
The Chronometer Oven 171
The Transit Pavilion 174
‘Lost in the Birkenhead’ 179
The Transit Circle 189
The Mural Circle 195
Airy’s Altazimuth 208
New Altazimuth Building 211
The New Altazimuth 213
The New Observatory as seen from Flamsteed’s Observatory 219
The Self-registering Thermometers 235
The Anemometer Room, North-west Turret 240
The Anemometer Trace 243
Magnetic Pavilion—Exterior 246
Magnetic Pavilion—Interior 248
The Dallmeyer Photo-heliograph 254
Photograph of a Group of Sun-spots 259
The Great Nebula in Orion 269
The Half-prism Spectroscope on the South-east Equatorial 273
The Workshop 276
The 30-inch Reflector with the New Spectroscope attached 278
‘Chart Plate’ of the Pleiades 286
The Control Pendulum and the Base of the Thompson Telescope 289
The Astrographic Telescope 291
The Driving Clock of the Astrographic Telescope 294
The Thompson Telescope in the New Dome 297
The Nebulæ of the Pleiades 300
Double-star Observation with the South-east Equatorial 308
The South-east Dome with the Shutter Open 314

GENERAL VIEW OF THE OBSERVATORY BUILDINGS FROM THE NEW DOME.
(From a photograph by Mr. Lacey.)


THE ROYAL OBSERVATORY

GREENWICH


CHAPTER I

INTRODUCTION

I had parted from a friend one day just as he met an acquaintance of his to whom I was unknown. ‘Who is that?’ said the newcomer, referring to me. My friend replied that I was an astronomer from Greenwich Observatory.

‘Indeed; and what does he do there?’

This question completely exhausted my friend’s information, for as his tastes did not lead him in the direction of astronomy, he had at no time ever concerned himself to inquire as to the nature of my official duties. ‘Oh—er—why—he observes, don’t you know?’ and the answer, vague as it was, completely slaked the inquirer’s thirst for knowledge.

It is not every one who has such exceedingly nebulous ideas of an astronomer’s duties. More frequently we find that the inquirer has already formed a vivid and highly-coloured picture of the astronomer at his ‘soul-entrancing work.’ Resting on a comfortable couch, fixed at a luxurious angle, the eye-piece of some great and perfect instrument brought most conveniently to his eye, there passes before him, in grand procession, a sight such as the winter nights, when clear and frosty, give to the ordinary gazer, but increased ten thousand times in beauty, brilliance, and wonder by the power of his telescope. For him Jupiter reveals his wind-drifted clouds and sunset colours; for him Saturn spreads his rings; for him the snows of Mars fall and melt, and a thousand lunar plains are ramparted with titanic crags; his are the star-clusters, where suns in their first warm youth swarm thicker than hiving bees; his the faint veils of nebulous smoke, the first hint of shape in worlds about to be, or, perchance, the last relics of worlds for ever dead. And beside the enjoyment of all this entrancing spectacle of celestial beauty, the fortunate astronomer sits at his telescope and discovers—always he discovers.

This, or something like it, is a very popular conception of an astronomer’s experiences and duty; and consequently many, when they are told that ‘discoveries’ are not made at Greenwich, are inclined to consider that the Observatory has failed in its purpose. An astronomer without ‘discoveries’ to his record is like an angler who casts all day and comes home without fish—obviously an idle or incompetent person.

Again, it is considered that astronomy is a most transcendental science. It deals with infinite distances, with numbers beyond all power of human intellect to appreciate, and therefore it is supposed, on the one hand, that it is a most elevating study, keeping the mind continually on the stretch of ecstasy, and, on the other hand, that it is utterly removed from all connection with practical, everyday, ordinary life.

These ideas as to the Royal Observatory, or ideas like them, are very widely current, and they are, in every respect, exactly and wholly wrong. First of all, Greenwich Observatory was originally founded, and has been maintained to the present day, for a strictly practical purpose. Next, instead of leading a life of dreamy ecstasy or transcendental speculation, the astronomer has, perhaps, more than any man, to give the keenest attention to minute practical details. His life, on the one side, approximates to that of the engineer; on the other, to that of the accountant. Thirdly, the professional astronomer has hardly anything to do with the show places of the sky. It is quite possible that there are many people whose sole opportunity of looking through a telescope is the penny peep through the instrument of some itinerant showman, who may have seen more of these than an active astronomer in a lifetime; while as to ‘discoveries,’ these lie no more within the scope of our national observatory than do geographical discoveries within that of the captain and officers of an ocean liner.

If it is not to afford the astronomer beautiful spectacles, nor to enable him to make thrilling discoveries, what is the purpose of Greenwich Observatory?

First and foremost, it is to assist navigation. The ease and certainty with which to-day thousands of miles of ocean are navigated have ceased to excite any wonder. We do not even think about it. We go down to the docks and see, it may be, one steamer bound for Halifax, another for New York, a third for Charleston, a fourth for the West Indies, a fifth for Rio de Janeiro; and we unhesitatingly go on board the one bound for our chosen destination, without the faintest misgiving as to its direction. We have no more doubt about the matter than we have in choosing our train at a railway station. Yet, whilst the train is obliged to follow a narrow track already laid for it, from which it cannot swerve an inch, the steamer goes forth to traverse for many days an ocean without a single fixed mark or indication of direction; and it is exposed, moreover, to the full force of winds and currents, which may turn it from its desired path.

But for this facility of navigation, Great Britain could never have obtained her present commercial position and world-wide empire.

‘For the Lord our God most High,
He hath made the deep as dry;
He has smote for us a pathway,
To the ends of all the earth.’

Part of this facility is, of course, due to the invention of the steam engine, but much less than is generally supposed. Even yet the clippers, with their roods of white canvas, are not entirely superseded; and if we could conceive of all steamships being suddenly annihilated, ere long the sailing vessels would again, as of yore, prove the

‘Swift shuttles of an empire’s loom,
That weave us main to main.’

But with the art of navigation thrust back into its condition of a hundred and fifty years ago, it is doubtful whether a sufficient tide of commerce could be carried on to keep our home population supplied, or to maintain a sufficiently close political connection between these islands and our colonies.

Navigation was in a most primitive condition even as late as the middle of last century. Then the method of finding a ship’s longitude at sea was the insufficient one of dead reckoning. In other words, the direction and speed of the ship were estimated as closely as possible, and so the position was carried on from day to day. The uncertainty of the method was very great, and many terrible stories might be told of the disastrous consequences which might, and often did, follow in the train of this method by guess-work. It will be sufficient, however, to cite the instance of Commodore Anson. He wanted to make the island of Juan Fernandez, where he hoped to obtain fresh water and provisions, and to recruit his crew, many of whom were suffering from that scourge of old-time navigators—scurvy. He got into its latitude easily enough, and ran eastward, believing himself to be west of the island. He was, however, really east of it, and therefore made the mainland of America. He had therefore to turn round and sail westwards, losing many days, during which the scurvy increased upon his crew, many of whom died from the terrible disease before he reached the desired island.

The necessity for finding out a ship’s place when at sea had not been very keenly felt until the end of the fifteenth century. It was always possible for the sailor to ascertain his latitude pretty closely, either by observing the height of the pole-star at night or the height of the sun at noonday; and so long as voyages were chiefly confined to the Mediterranean Sea, and the navigators were content for the most part to coast from point to point, rarely losing sight of land, the urgency of solving the second problem—the longitude of the ship—was not so keenly felt. But immediately the discoveries of the great Portuguese and Spanish navigators brought a wider, bolder navigation into vogue, it became a matter of the first necessity.

To take, for example, the immortal voyage of Christopher Columbus. His purpose i

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