Map of the Heavens.

Feilding Star, Volume xv, Issue 335, 9 June 1894, Page 4

Map of the Heavens.

o The scheme of producing a vast photographic nap of the heavens, which was agreed upon by the congress of fifty- eight astronomers, »c » resenting fifteen distinct nationalities, which met in Paris five years ago, is stated by Mr R. A. Gregory in Good Words to be now well advanced. Two English observatories are taking part iv ihis self-appointed task, Greenwich Observatory and Oxford University. The telescopes employed by all the co-operating astronomers are substantially the^same as that constructed by Sir Howard Grubb. Two tube* are rigidly connected, the lower being merely a long camera, and the upper an ordinary telescope The astronomical photographer uses thejtelescope us a view-finder. When he sees through it the bit of celestial scenery, of which he desires a permanent picture, he places a sensitised plate in the lower end of his long camera, and starts the clock which keeps the telescope moving at the same rate as the heaven's vault. The machine can then be left to itself, for it will do the sky sketching automatically. More than twenty-two thousand celestials 6CPnes will, it is stated, have to be photographed in this manner, and the patch- work map which they produce will cover the surface of a globe twenty-four feet in diameter.