The blackout has made us very conscious of the light of the night sky. On clear moonless nights, the light coming from the sky is quite sufficient to enable us to see the outline of such things as trees, houses, etc., or even of the mountains miles away. On cloudy nights, on the other hand, the limit of visibility is practically reduced to zero.
Before leaving 1943 we should remember Copernicus, for the thoughts of astronomers all over the world have been, with him this year. He died in 1543, 400 years ago, and on his death bed a printed copy of his great book was handed to him. This book contained his thoughts and reasonings on the ""heavens and the earth"" and as they were such as to overturn the ideas of the men of science and ecclesiastics of his time, he had not dared to publish it before.