"As Nelson swept the seas you sweep
the skies, leaving little for those who may come after you."
Letter
from Thomas Maclear to John Herschel,
Royal Observatory, April 5, 1834 |
ON JANUARY 15, 1834
there arrived at the Cape a young English scientist and philosopher who for
sheer drive, intellectual capacity and versatility has had few equals in the
long history of callers at Table Bay."
"John Frederick William Herschel, Bart., K.H. was born at
Slough, near Windsor, on the 7th March, 1792 and died at Collingwood, Kent on
the 11th May, 1871, in his eightieth year. He was the only child of Sir
Frederick William Herschel and, like his father, was one of the greatest
astronomers of all ages."
"In 1820, assisted by his father, [John Herschel]
completed a mirror of 18 inches diameter and 20 feet focal length [f/13] which
became the heart of the telescope with which much of his later observing was
done."
"...there was an air of dilettantism about Herschel. His
mind ranged over a vast number of subjects ... but when it came to physical hard
work his enthusiasm would often flag ... Professor Pritchard in his biographical
notice in the Encyclopaedia Britannica wrote 'Herschel had become an astronomer
from a sense of duty, just as his father had become one by fascination and fixed
resolve: hence it was by filial loyalty to his father's memory that he was now
impelled to undertake the completion of that work which at Slough had been so
grandly commended. William Herschel had explored the northern heavens; John
Herschel determined to explore the heavens of the south, as well as re-explore
the north.' "
Evans continues: "We need now to envisage Herschel some
time in 1832: He is one of the most celebrated scientists in Europe, a knight,
honored by numerous scientific bodies, happily married, acquainted with all the
most distinguished scientists of Europe, a polyglot, with German, French,
Italian, Latin and Greek at his command. He has made a name for himself in
mathematics, astronomy, chemistry and several other fields. Now he thinks of
observing the southern sky just as he has done the northern, and he seeks for a
place to carry out his ambition. The choice is very limited . . . South America,
South Africa, and Australia." For obvious reasons he chose South Africa; it
offered, amongst others, "an astronomical tradition and an active
observatory, a healthy climate, and a convenient longitude."
"To achieve this object, he and his family set sail from
England late in 1833 aboard the East Indiaman, the 'Mountstuart Elphinstone'.
After a voyage of two months they came ashore, Herschel himself, his wife, the
four children Caroline, Emilia Mary, William James, and Isabella. Then there
was the mechanic, John Stone, who had in his charge the 20-foot reflector of 18
inches aperture (with classical pedantry the mirrors provided for it were often
referred to as 'sesquipedalian') and an equatorially mounted refractor of 5
inches diameter and 7 feet focus [f/17]."
For the next four years, Herschel swept the southern skies,
producing a detailed catalogue of non-stellar objects, published in 1847 as "Results
of Astronomical Observations made during the years 1834, 5, 6, 7, 8, at the Cape
of Good Hope; Being the completion of a telescopic survey of the whole surface
of the visible heavens, commenced in 1825"
This southern catalogue gives positions and descriptions for
1708 objects, of which 98 also appear in his northern catalogue. Of these
objects, Herschel notes, "206 have also been identified, with more or less
certainty . . . with objects observed by Mr Dunlop, and described in his
Catalogue of Nebulae. The rest of the 629 objects, comprised in that catalogue,
have escaped my observation; and as I am not conscious of any such negligence in
the act of sweeping as could give rise to so large a defalcation, but, on the
contrary, by entering them on my working lists . . . took the usual precautions
to ensure their rediscovery; and as I am, moreover, of opinion that my
examination of the southern circumpolar region will be found, on the whole, to
have been an effective one, I cannot help concluding that, at least in the
majority of those cases, a want of sufficient light or defining power in the
instrument used by Mr Dunlop, has been the cause of his setting down objects as
nebulae where none really exist. That this is the case, is many instances, I
have convinced myself by careful and persevering search over and around the
places indicated in his catalogue."
Some interesting objects and comments appear in his observing
logs; some of these can be found on the "Notes from h's Cape Diaries"
page.
"Herschel died in 1871 and is buried in Westminster Abbey
not far from Newton. Few men have done as much in their lives."
HERSCHEL'S CAPE
CATALOGUE can be downloaded
as an ASCII file. It lists Herschel's h number from the Cape Obs versus the
number in the NGC.
THE ABSTRACT OF
CHAPMAN'S ARTICLE in Vistas in Astronomy: "Sir John
Frederick William Herschel occupies a pivotal position in the history of British
astronomy. He formed the living link between two styles or traditions of science
by being the last major specimen of one breed, and the inspiration and
intellectual role model for the generation to follow. For John Herschel was
perhaps the last significant figure to devote himself wholly and full-time to
fundamental research in astronomy and its related sciences on the strength of a
private fortune. And while the stature that he enjoyed did much to stimulate the
concept of the 'professional' astronomer in Britain, so many of these men of the
rising generation who admired his thorough-going dedication to science were
themselves more obviously professional in the respect that they earned their
livings through academic science. One sees in him, therefore, an eclectic blend
of attitudes towards what science was, how it should be pursued, and how it
should be paid for. |
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