More from the Cooke at Mauritius

 

On the afternoon of November 14^th 1907 a transit of Mercury was observed from Mauritius using a 6 inch equatorial by Thomas Cooke & Sons York with a diagonal eyepiece power 80. I believe this was the same 6 inch Cooke that was used to observe the Transit of Venus in 1874.

The afternoon of the transit was cloudy but the Sun emerged from behind the clouds one minute before the internal contact at ingress. The Sun’s limb was boiling considerably; the definition of the limb was bad, but the spots at the centre and near the limb good.

Mercury appeared as a clear cut black disc, perfectly circular, with no white spot or fringe. No flashing across of cusps was detected.

Almost immediately after internal contact at ingress the Sun became obscured, and was not visible again until about 15 minutes before internal contact at egress. A careful watch was then made for any distortion, white spot, or disc, but none could be detected in the equatorial.