The most significant memorial [to Sir John Herschel] is the Herschel obelisk. On 28 November 1838 the Cape Governor, Sir George Napier, presided over a public meeting at which a committee was elected to raise funds for a permanent monument to the Herschels. The committee decided on an obelisk, and funds were raised by donations from the friends of the Herschels in Cape Town. The stone for the memorial was quarried at Craigleith, near Edinburgh, and shipped to the Cape, where it was erected in 1841.
The piece of ground around the obelisk was given to the Claremont municipality by the Herschel descendants in 1906, and in 1934 the obelisk was declared a national monument, one of the first to be so recognised. Today it is within the playground of Grove School. Its base is hollow and enclosed on only three sides, so that the granite cylinder that Herschel purchased and set at the centre of rotation of his great telescope can be seen. On one side of the obelisk there is a plaque which reads: 'During a residence of four years in this colony Sir John Herschel contributed as largely by his benevolent exertions to the cause of education and humanity as by his eminent talents to the discovery of scientific truth'.
To astronomers, the Herschel obelisk is looked upon almost as a shrine – it is where one of the greatest of their number laboured for four years and produced a unique book that laid the foundations of our knowledge of the southern heavens.
Immediately prior to his departure from Cape Town to England in 1838, Sir John Herschel sold the estate, ‘Feldhausen’,  on which he had erected his telescope and had conducted his astronomical observations, to Mr. R. J. Jones, an auctioneer. The property was sold with a servitude: a circular patch of ground 63 feet in diameter bounded by newly planted fir trees was to be kept in Sir John’s possession in perpetuity.  This area marked the spot on which the telescope had actually stood. At the centre of the circle Herschel placed a small cylindrical column of granite engraved ‘I. H. 1838’ representing his initials in Latin (for Ioannes Herschelius) and the year in which he had completed his work and was leaving the colony. Subsequently, the members of the South African Literary and Scientific Institution, of which Herschel had been President,  decided to commemorate his scientific achievements and his contributions to education in the Cape. At first they had the idea of devising a series of six gold medallions inscribed with the details of his scientific achievements. These had been paid for by a voluntary subscription and were designed by Herschel’s assistant, Charles Piazzi Smyth, whose father Rear-Admiral William Henry Smyth had recently (1834) published a catalogue of Roman Imperial
medals.However, more had been collected than was expended and so the members decided to widen the scope of the exercise and to erect a more suitable memorial on the ground on which the telescope had stood. A meeting of the subscribers chaired by the Governor, Sir George Napier, was held in November 1838 to decide on the form the memorial should take. The resolutions taken at the gathering stated that it was to be ‘a permanent memorial’ and, although no further information about its exact architectural form was given is given in the resolutions, it must be assumed from subsequent references that it was to be an obelisk.  The committee requested Professors Forbes and Henderson (who had been the second Royal Astronomer at the
Cape) to arrange for stone-cutters to make a yellow-granite obelisk from a granite slab taken from a quarry near Edinburgh. After considerable controversy about the final location of the monument (some wanted it to be erected on the Parade in Cape Town) it was erected on the Feldhausen estate (previously named ‘The Grove’) in 1841 (although the final piece was only added in February 1842). It is now a national monument (and has been since 1934) and still stands in the grounds of The Grove Primary School in Claremont.