John Herschel in South Africa
We give below a short extract from the article 'Alan Chapman, Sir John Herschel: The 'philosopher' of deep space, Astronomy Now (October 2022), 38-41'. We also give an extract from the article 'Herschel, John Frederick William [Sir]: Visiting Professional Astronomer, Astronomical Society of Southern Africa' (http://assa.saao.ac.za/sections/history/astronomers/j-f-w-herschel/) which mostly consists of extracts from P Moore and P Collins, Astronomy in Southern Africa (Robert Hale, London, 1977), P Smits, A Brief History of Astronomy in Southern Africa (unpublished), and B Warner, Astronomers at the Royal Observatory Cape of Good Hope (University of Cape Town, 1979).
1. John Herschel in South Africa, by Alan Chapman.
It was in order to complete the Herschel deep-sky survey across both hemispheres that Sir John would travel to South Africa. But it was not until the death of his beloved mother, Mary Pitt Baldwin Herschel, in 1832, that he and his young bride felt able to leave England for a sustained period. Then, John, Margaret, their constantly growing family, plus servants, finally departed from Southampton in the big East Indiaman Windsor Castle. Their first-class passage cost £500.
The Herschels were well off. William himself had been an astute businessman as well as an astronomer, while his twice-widowed wife Mary, John's mother, inherited money from stockbroking and landowning spouses. As one might notice, their one child, Sir John, never needed a paid job, in spite of his and Margaret's large number of offspring.
The voyage to South Africa was blessed with fair winds and calm seas, and they made landfall within two months of leaving England. John leased, then later purchased, the Feldhausen estate near Table Mountain, and there he set up the 18-inch reflector and began to 'sweep' the southern sky.
Yet the same nagging problem remained: what were the nebulae made of? The prevailing idea was that they were 'particulate', each composed of billions of individual particles, all exerting gravitational attraction upon each other. It would be another thirty years before William Huggins discovered gaseous nebulae.
Planetary nebulae were mysterious bodies, for while they displayed angular discs, just like planets, they were in the depths of stellar space. We now know them to be gas clouds spewed out by dying stars.
Astronomy in South Africa, however, had its hazards that one would not encounter in Slough. When climbing the steep ladders to the observing platform of the 18-inch in the dark, for instance, one had to be on the alert for poisonous snakes! Likewise, packs of feral dogs, escaped from farms, sometimes prowled the veldt at night, and might fancy a tasty astronomer for supper. Hearing the growling pack below, Sir John would discharge a double-barrelled pistol loaded with buckshot into the thick of them, which soon drove them away squealing.
Snakes also got into their beautiful house, and one suddenly reared up in front of Margaret in the drawing room. She dispatched it with poker and fire tongs. And when John, Margaret, and their growing brood went out to enjoy a picnic on a nearby beach, John always took his rifle along, in case lions or other big beasts caught their scent and came too close.
The family enjoyed a firm friendship with the new Astronomer Royal at the Cape, Sir Thomas Maclear, who was also a qualified medical doctor and acted as the Herschel's GP. On one occasion he skilfully whipped out one of Margaret's troublesome teeth while she was fully conscious! (Sulphuric ether was first used as an inhaled anaesthetic in 1846.)
By 1838, John had completed his great southern sky 'sweep'. and set sail for home. Selling Feldhausen for a handsome profit, the now even larger Herschel family booked a first-class passage on the Mountstuart Elphinstone Indiaman, and were blessed with another storm-free voyage home.
2. Herschel, John Frederick William [Sir]: Visiting Professional Astronomer.
It is often supposed that Herschel was in some way officially connected with the Royal Observatory. He was not; but his presence during the early years of Maclear's work there was invaluable. [Thomas Maclear (1794-1879), born in Ireland, was Her Majesty's astronomer at the Cape of Good Hope.] The two men became fast friends, a friendship founded on mutual respect; it is not too much to say that had it not been for Herschel, with his constant stream of helpful suggestions and his warm personality, the first four years of Maclear's work would have been much less pleasant than they actually were - and considerably less fruitful. At this stage Herschel was world-famous, while Maclear was at the start of his astronomical career. It has been said that at the beginning of their association it was Herschel who provided the necessary impetus, while Maclear was still groping uncertainly to decide exactly where his most useful work might lie. Later, the roles were somewhat reversed, as Maclear's self-confidence grew. Whatever may be the truth of it, the two men remained firm friends to the end of their lives. As a matter of fact, Herschel and Maclear were friends in the U.K., and Herschel's move to Cape Town helped to make up Maclear's mind to accept the post as Her Majesties Astronomer at the Cape of Good Hope. They arrived in Cape Town a few days apart.
Once at Cape Town, Herschel stayed at Feldhausen. At first he rented and later purchased the estate in that is located on the border between Wineberg and Claremont. His decision was influenced by the previous director of the Cape Observatory, Thomas Henderson. Henderson detested the site of the Cape Observatory and commented to Herschel that the Wineberg area is much better suited for astronomy and better protected from the wind. Some of the prominent visitors he received, included Charles Darwin; Sir John Franklin (discoverer of the Northwest Passage) ...
Herschel had been pursuing his programme of cataloguing the clusters, nebulae and double stars of the southern sky. His father, Sir William, had devised a method of observation, which he termed sweeping. This was done by fixing his telescope at a particular declination and recording the objects, which were carried through the field of view by virtue of the Earth's rotation. Sir John swept in declination; he was remarkably accurate and even today some of his observations have not been bettered.
In his four years at the Cape, Herschel had accomplished his aim of surveying the southern sky, discovering in the process 700 nebulae, 100 double stars and a miscellany of other astronomical notabilia. True, his catalogue of nebulae has stood the test of time more successfully than his list of double stars. In many cases he listed optical pairs - that is to say, doubles which are not made up of two stars which are genuinely associated. However, his catalogue of nebulae was first-class. It even contained several objects which we now know to be external galaxies, many of which are spiral in shape (though the spiral forms were not described until 1845, by the Earl of Rosse - with the aid of his vast 72-inch reflector at Birr Castle in Ireland).
Herschel's drawings were, in the main, excellent, but are not consistent; it has often been commented that some easily-observed objects were inaccurately represented, while the much more difficult ones were drawn with surprising correctness. One feature to which he devoted special attention was the nebulae round the erratic variable star Eta Argus, now known as Eta Carinae. (The old constellation of Argo Navis, the Ship, has been split up; Carina is its keel - containing Canopus, the second brightest star in the sky.) Herschel spent many nights in drawing the nebula, and he also made notes about the rise to brilliance of Eta … At this time Eta Carinae was probably the most luminous star in the entire Galaxy, but since Herschel's time it has fallen from grace, and for almost a hundred years now it has been invisible to the naked eye. Today it looks very red, and is obviously not a normal kind of star; it is in a class of its own. Astronomers would dearly like to see another outburst. Few accurate estimates of it were made when it was near its peak, so that Herschel's observations were timely.
As a further aside, Herschel was also the last to record Halley's Comet as it receded from the Sun after passing perihelion in 1835.
To carry out his work of cataloguing, Herschel had to know the right ascensions and declinations of marker stars which acted as reference points when he wanted to measure the positions of the new objects which he was discovering night after night. In this he was greatly assisted by Maclear, who obtained the required information by using the transit circle and mural circle which had been sent out and set up at the Royal Observatory.
Herschel's influence on cultural matters while in residence at the Cape was very great. With a small, carefully-chosen committee he laid the foundations of education in South Africa, and was assiduous in ensuring that it was put into effect after he returned to England. This committee had far reaching impact on the history of South Africa.
Herschel assisted Maclear in setting up a Meteorological Committee. He also sketched various indigenous flowers.
When he announced that his astronomical work had been completed, and that he was about to leave the Colony, the South African Literary and Scientific Institution, of which he was President, gave him a specially-designed gold medal which he cherished above many of the other honours which were bestowed on him. The medal was acquired by The South African Museum, where it was stolen.
Herschel made a great impact on Cape society and when he left the idea was proposed to erect a monument to him. A newspaper war ensued over the best site. The Grand Parade was proposed but those who proposed the Feldhausen won. A fund was raised to erect a monument on the spot where his 20-ft. reflector had stood; and after his departure, this was done. As we have noted, it took the form of an obelisk. It was carved from giant blocks of Craigleath stone from a quarry outside Edinburgh, and it arrived in two packing cases in August 1841. Work on the monument took six months to complete. In its foundations were buried glass bottles filled with silver and copper coins; there were also inscription medals and medals of the South African Institution bearing statistical and geographical notices relating to the Colony. There were engravings of nebulae observed by Herschel at Slough, together with a plan of Maclear's triangulation, connecting Feldhausen with the site of La Caille's observatory and the Royal Observatory, four miles away. Other items, such as details of the discoveries made by Captain Ross in the south Polar Regions in 1841, and the measurement of the arc of the meridian in 1842, were added before the base of the structure was finally sealed. The Obelisk was declared a National Monument.
A picture of the obelisk is at THIS LINK.
Last Updated February 2023