Searching for the Ether
the reticule was measured with the aid of the ocular micrometer of the second telescope.
Using this device, Courvoisier made two series of observations in 1926 and 1927. Afterwards, he had a special instrument built for this purpose, and made a third series of observations in 1932.
In his first experiments the telescopes were placed in a vertical plane in the East-West direction. In 1926 and 1928 Courvoisier built two new instruments that could be rotated. He expected that this would improve his measurements. However, he found out that it was impossible to compare measurements when the device was rotated, due to mechanical problems, and the instruments could only be effectively used in a fixed position.
The equation used to compute the effect was similar to that used in the case of the observation of stars, but instead of the North component of the speed, it was necessary to take into account the West component. As in the former case, the resulting equation has a constant term plus variable components with periods of one sidereal day and half sidereal day.
Fig. 6. Courvoisier’s double telescope apparatus for measuring the motion of the Earth through the ether.
Roberto Martins Searching for the Ether DIO 17
Table 1. Measurements made by Courvoisier in 1926 with the double telescope instrument.
Table 2. Measurements made by Courvoisier in 1927 with the double telescope instrument.
The first series of measurements was made from 31 July and 6 August 1926, with observations spanning between 3 and 20 o'clock sidereal time; the second one, from 28 February to 29 May 1927, with observations covering the period from 21 to 13 o'clock sidereal time. Both series comprised more than 500 measurements. Tables 1 and 2 shows the mean results obtained by Courvoisier for each sidereal time: