Finsen WS

FINSEN,  “Bill” W S  [Dr]

Professional Astronomer

In brief :
Famous for:
Director of the 
Republic Observatory 1957 – 1965
Developed  the 
Finsen Eyepiece Interferometer.
Discovered 73 double stars.
Took 54 000 photographs of Mars.  These were considered to be the best photographs of Mars until the space probes became available.
Finsen became the director of the Republic Observatory in 1957. During his time as Director, the South African  Government decided to close down the Republic Observatory and amalgamate all the astronomical services into what became the S.A.A.O.  Finsen was ardently opposed to this decision (as were many other), but he could not stop the decision.

Historical background :
Van  den Bos had been succeeded by Dr W. S. Finsen, who had devoted  his life to the Observatory and who was yet another outstanding  astronomer who specialised in double stars and in minor planet work. Finsen’s achievements matched those of any of his predecessors, and he was responsible for some vital improvements in instrumentation; he it was who developed what is called the eyepiece interferometer, a device which could be attached  to a telescope to help in measuring very close double stars.  Finsen found 73 new pairs, examined over 8 000 stars, and measured  the orbital motions of many binaries. For this work, of course  he used the 263-inch, generally with a magnification of 620. He also concentrated upon the photography of the planet Mars and obtained the best results available before the first space probe flew past the Red Planet in 1965. Finsen took 54 000 photographs of Mars altogether. There was yet another branch of  research in which he was pre-eminent; his observations and predictions of the first artificial satellites made up a vital link in the chain.”[Copied from Collins p.104.]
Director of the Republic Observatory 1957 – 1965
He was a very good and much sought after public speaker. [Personal  Communication with Peter Smits who knew him]


Link to the Telescope Manufacturers.


Link to the Main Bibliography Section and more information about Sources.

Remaining  Artifacts:
Finsen Eyepiece Interferometer.

Laing, J.D. (ed.), The Royal Observatory at the Cape of Good Hope 1820  – 1970 Sesquicentennial Offerings, p.
Moore, P. & Collins, P.; Astronomy in Southern Africa, p99; pp.104  – 106  (General Source)
History  of Astronomy Questionnaire Reply (R no.)
Overbeeck, D., W.S. Finsen: More than a Double Star Observer, MNASSA, Vol.  56, Nos. 9 & 10, 1997 October.

By Finsen:
W. S. Finsen and C. E. Worley Third Catalogue of Orbits of Visual Binary Stars, Rep. Obs. Circ. (Johannesburg), No. 129, 1970
Finsens publications on Interferometric Observations:

External Link
Finsen, W.S., Union Obs. Circ. 3, 379, 1933
Finsen, W.S., Union Obs. Circ. 4, 134, 1935
Finsen, W.S., Union Obs. Circ. 6, 94, 1951
Finsen, W.S., MNASSA 11, 30, 1952
Finsen, W.S., MNASSA 12, 86, 1953
Finsen, W.S., Union Obs. Circ. 6, 170, 1953
Finsen, W.S., Union Obs. Circ. 6, 240, 1954
Finsen, W.S., MNASSA 14, 1955
Finsen, W.S., Union Obs. Circ. 6, 259, 1956
Finsen, W.S., MNASSA 16, 113, 1957
Finsen, W.S., Union Obs. Circ. 6, 302, 1958
Finsen, W.S., Union Obs. Circ. 6, 315, 1959
Finsen, W.S., MNASSA 18, 31-150, 1959
Finsen, W.S., MNASSA 19, 28-97, 1960
Finsen, W.S., Union Obs. Circ. 6, 333, 1960
Finsen, W.S., MNASSA 19, 178, 1960
Finsen, W.S., Union Obs. Circ. 6, 367, 1961
Finsen, W.S., Republic Obs. Circ. 7, 10, 1962
Finsen, W.S., Republic Obs. Circ. 7, 32, 1963
Finsen, W.S., Republic Obs. Circ. 7, 53, 1964
Finsen, W.S., Republic Obs. Circ. 7, 79, 1965
Finsen, W.S., Republic Obs. Circ. 7, 108, 1966
Finsen, W.S., Republic Obs. Circ. 7, 138, 1967
Finsen, W.S., Republic Obs. Circ. 7, 187, 1969
Finsen, W.S., Unpublished, manuscript or reference not found.

Remaining Artifacts:
Saxonworld Military History Museum: Simple sun compass (Reference:)

Related External Links:
Fourth Interferometric Catalog :
Third Speckle Catalog:
Fourth Catalog of Orbits of Visual Binary Stars:
Simple Sun Compass:
Obituary Notes:


Source: Moore

The object at the eyepiece is the interferometer desinged by Finsen.