The Eclipse of the Sun

1900 001

Second Contact, 1900, May 28th
(Photographed at Wadesborough, U.S.A., by Mr. J. N. Maskelyne, with 3.5-inch kinematograph)
©  E. WALTER MAUNDER, F.R.A.S., The Total Solar Eclipse 1900, London, Knowledge Office, 1901


The Eclipse of the Sun 


1 Maskelyne  
2 John Nevil Maskelyne
"The Eclipse of the Sun," taken by Mr. Nevil Maskelyne, F.R.A.S.
Folkestone, Hythe, Sandgate & Cheriton Herald, Saturday 01 September 1900, p. 8.
3 28/05/1900  
[From Our Own Correspondent.]
NEW YORK, May 29.-Mr. Maskelyne, of the British Astronomical Association, took six hundred cinematograph photographs; 350 during the period of totality.
Birmingham Daily Post, Wednesday 30 May 1900, p. 10.
4 États-Unis, Wadesborough  


07/09/1900 Grande-BretagneFolkestone
[David Devant]
The Eclipse of the Sun
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Tournage de l'Eclipse du soleil (mai)

E. WALTER MAUNDER, F.R.A.S., The Total Solar Eclipse 1900, London, Knowledge Office, 1901.

maskelyne 1900 02

At Washington we were joined by our chief colleague, Mr. Nevil Maskelyne, F.R.A.S., to whom a terrible mischance had occurred. He was the designer of the kinematograph telescope, the film of which had been mysteriously stolen when in my custody at the last eclipse in India, and now by another strange fatality the optical part of the same instrument was missing, having by an oversight never been shipped in London, and thus a second time this novel instrument seemed for the moment doomed to failure.
But our unrivalled mechanician, whose genius is so well known to every frequenter of the Egyptian Hall, had already determined on the Herculean task of manufacturing an adequate telescope and fittings from selected photographic lenses, and of completing the work within the three or four working days that at most would be at his disposal. The endeavour was like that of a sailor attempting single-handed to rig a jury mast under stress of weather when his main mast had gone by the board; but our friend faced it, and so, having caught us up, was hurrying down to the front with a jaded look, in sooth, but with set purpose in his eye. p. 7-8.
But in spite of little twilight there were daylight hours early and late when work could and did get on apace, and when two days later the rest of the party joined us preparations were fairly advanced. Mr. N. Maskelyne was still slaving at his stupendous task which was eventually crowned with complete success. Mrs. Maskelyne kindly took over the management of a clock-driven actinometer which at my desire her husband had designed. Miss Woolston elected to confine her attention to photographing the Corona, Miss Dixon took charge of the opera glass spectroscope, the same instrument that she had used at the eclipse at Buxar, Mr. G. Dixon, whose skill as an operator is second to none, essayed single handed to take photographs of the Corona with a three inch o.g. by Dollond, and with a tele-photo camera. My daughter was provided with a battery of four cameras, with which she proposed to photograph the outer extensions, using Dallmeyer and other lenses ranging from f/6 to f/12. I myself was using the same telescopic camera of 4.1 o.g. with which my son had successfully photographed the inner Corona at Buxar. Other work of a minor character was also undertaken, and the day before the Eclipse our camp unexpectedly received the addition of Mr. Hadden, an American member of the B.A.A., using a three inch equatorial refractor. p. 13.
BESIDE our attempt to photograph the long coronal streamers, one great object with us in the recent eclipse was to push a little further the experiment which we had made in India in photographing the corona out of totality. For this purpose we took in all some forty photographs during the partial phase, with varying instruments and exposures, and our experiments have been very strikingly supplemented by the work which Mr. Nevil Maskelyne, F.R.A.S., carried on with his kinematograph in America. Mr. Maskelyne's instrument had an aperture of 3 1/2 inches, which was stopped down before and after totality to an aperture of 3/8th of an inch. The instrument was run for about 5 ¾ minutes, commencing some 25 seconds before totality, and running for nearly 4 minutes after totality was ended. In all 1187 exposures were made, 87 before totality, 299 during totality, and 801 after. The corona is seen very definitely on the first exposure, and can be traced right away to number 841, that is to say, to number 455 after the return of sunlight. Allowing 0.29 seconds for the mean interval between the middle of one exposure and that of the next, this gives us for the last photograph showing the corona, the time 2m. 12s. after the return of sunlight. This duration is worked out by assuming that the duration of the photographic eclipse was the same as that of the visual, the latter having been observed by Prof. Flint with a 3-inch equatorial, at the same station of Wadesborough. p. 143.
Mr. Maskelyne's kinematograph film is of special interest by the way in which it enables us to trace the gradual fading of the corona in the face of the increasing sunlight. The aperture was the same with all the film photographs -after the diaphragm was put on,- the exposure was the same in all cases, the only variable was the increasing arc of sunlight. The exposure was equivalent to about 1/60th of a second with f/15, and the film may be considered as about as quick as an ordinary "rapid" plate. It is very instructive of the conditions of the problem to note how quickly, after the first bead of sunlight is seen, the outer corona fades and disappears; and also that when the aperture is cut down, diminishing the exposure almost to 1/90th of what it was when the aperture was full, the corona is almost lost at first, but reappears, and for some little time becomes stronger as the sunlight strengthens, fading again when the sky-glare becomes too strong for that exposure and aperture. There can be no doubt that could the exposure have been gradually shortened as the sunlight gradually increased, the corona would have been traced on the film further still. p. 145.
To sum up, we learn from Mr. Maskelyne's film, that to secure the inner corona from half-minute to one minute after totality is over, an exposure of about one-hundredth of what is necessary for a full representation of the corona in totality is required. Earlier the exposure should be somewhat longer for best effect, later it should be diminished. In this way Mr. Maskelyne has followed the corona two minutes and twelve seconds after totality on a single coated film, and we have increased our Indian record of thirty-nine seconds to five minutes, very faintly shown on a Sandell triple-coat, and this again is extended to eight minutes by Mr. Willis's photograph. The advance made is a real advance indeed, but exceedingly small as compared with the full magnitude of the problem. Indeed our progress is rather towards a truer appreciation of its difficulties than towards its solution.
A. S. D. MAUNDER. p. 146.

E. WALTER MAUNDER, F.R.A.S., The Total Solar Eclipse 1900, London, Knowledge Office, 1901.

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