Transit of Mercury seen from Canada with a Cooke

 

Dr Donaldson of Fergus, Ontario was among many astronomers who watched the transit of Mercury on the May 8th/9th 1891. He used his 3.5 inch Cooke refractor and was singularly fortunate in his observations.

He reported that internal contact occurred at 6.57.45 Eastern Standard Time and that from the time the planet, as a wedge apparently, began to cut into the solar limb until it stood “clear, black, and distinct on the sun’s disc, only a very fine rim of brilliant light separating it from the outer darkness beyond the limb”, the “black-drop” was very noticeable and that evidence of it did not disappear until Mercury was well in the disc.