The stars in the afternoon

The stars in the afternoon - these are the stars above our heads, which six months ago were visible at night and six months later will decorate the night sky again. Illuminated Earth's atmosphere prevents us from seeing them, because air particles scatter the sun's rays in a larger amount than they send us stars.

The stars in the afternoon - these are the stars above our heads, which six months ago were visible at night and six months later will decorate the night sky again

A simple experience can clearly illustrate the disappearance of the star in the daytime in daylight. In the side wall of the cardboard box, several holes are punched, arranged like a star, and a sheet of white paper is pasted from the outside. The box is placed in a dark room and illuminated from the inside: on the punched wall, then clearly illuminated from the inside holes - this is the stars in the night sky. But it is only necessary, without stopping the lighting from inside, to light in the room a bright enough lamp, and artificial stars on a sheet of paper disappear without a trace: this is how the stars are extinguished in the afternoon.

It is often necessary to read that from the bottom of deep mines, wells, tall chimneys, etc., one can distinguish between the stars in the daytime. This widespread belief, supported by references to authoritative names, only recently was subjected to a critical test and was not confirmed.

In fact, none of the authors who wrote about it - from Aristotle in antiquity to John Herschel in the 19th century. - I did not see a single star in the daytime. All refer to the certificate of third parties. How much, however, there are little reliable evidence of "eyewitnesses", shows the following curious example. An article appeared in the American magazine that included the visible stars from the bottom of the wells in the daytime to the number of fables. This opinion was vigorously refuted by a letter from a farmer who claimed that he himself had seen Capellus and Algol himself from a 20-meter silo tower during the day. The audit found, however, that at the latitude where the observer's farm is located, these stars do not occur at the zenith at the indicated time of the year during the day and, therefore, could not be seen from the depth of the tower.

Theoretically, there is no reason why a mine or well can help to see the stars in the daytime. As we have already said, the stars are not visible during the day because they are drowning in the light of the sky. This condition does not change for the eye placed on the bottom of the shaft. Only the side light disappears throughout the shaft, but the rays emitted by all particles of the air layer above the hole in the shaft must continue to interfere with the visibility of the stars.

What matters in this case is that the walls of the well protect the eyes from the bright rays of the Sun; But this can only facilitate the observation of bright planets, not stars.

In telescope the stars are seen by day not because many think that they are looked at from the bottom of the pipe, but because the refraction of the rays in the glasses or reflection in the mirrors weakens the brightness of the section of the sky in question, while the brightness of the star itself (represented as a dot), on the contrary, increases. In a telescope having a lens 7 cm in diameter, you can already see the stars in the day of the first and even second magnitude. But the wells are not applicable to wells, mines, chimneys. Another thing is bright planets: Venus, Jupiter, Mars in the confrontation. They shine much brighter than stars, and therefore, under favorable conditions, can be seen during the day.