12 June

1967: On 12 June 1967, the USSR launched Venera 4, a Venus atmospheric probe.

It arrived at Venus on 18 October 1967 and was the first probe to be placed directly in the atmosphere and to return atmospheric data. It was crushed by Venusian atmospheric pressure before it reached the surface.

1843: On 12 June 1843, Sir David Gill was born.

He was a Scottish astronomer known for his measurements of solar and stellar parallax, showing the distances of the Sun and other stars from Earth.

From his first training as a watchmaker, he progressed to the timekeeping requirements of astronomy. He designed, equipped and operated a private observatory near Aberdeen.

In 1877, Gill and his wife measured the solar parallax by observing Mars from Ascension Island. To determine parallaxes, he perfected the use of the heliometer, a telescope that uses a split image to measure the angular separation of celestial bodies. He later redetermined the solar parallax to such precision that his value was used for almanacs until 1968.