You can observe the passage of Venus through the solar disk by means of buried glass, binoculars, a small pipe or a telescope. There is another way of observing. So, if you point the instrument at the sun and not look at the eyepiece, but place a sheet of white paper at some distance from it, you can see a magnified image of the Sun with its spots and passing Venus. A similar effect occurs as a result of the scattering of rays by an eyepiece.
On 26 May 1761, the simultaneous observation of this astronomical event was conducted by about 100 scientists at various points around the globe, allowing the distance to be calculated Suns. This method of calculating the astronomical unit was proposed by the famous scientist E. Halleem as early as 1691. According to this method, it was necessary to record from distant positions the exact time from the beginning of Venus’s first touch of the edge of the solar disk to the last.
In the observation of 1761 participated and M. IN. Lomonosov. The planet in the background of the solar disk looks like a small black circle. At the moment of Venus’s first “touch” of the Sun, a thin light border can be seen around it. It also drew attention to Lomonosov, having concluded that this border is visible from – for refraction of the atmosphere of the planet’s atmosphere of sunlight. In other words, the greatest Russian scientist was made an important discovery: Venus has an atmosphere.