Monday, March 10, 2014

The Transits of Venus

The transit of Venus 2012
The 2012 transit of Venus by Michael Umbricht

Ladd Observatory
The June 5, 2012 transit of Venus across the Sun at 6:21:38 PM EDT captured using a modern digital camera through the historic main telescope at Ladd Observatory.

The telescope is a refractor with 12" aperture and 15' focal length. A solar pre-filter was used on the objective of the telescope and the camera used a broadband hydrogen alpha nebular filter to further reduce the brightness due to the sensitivity of the camera. The weather was mostly cloudy during the day and this image was taken during a brief thinning of the clouds which gives the Sun's surface a mottled appearance. 

The photo at left shows Michael Umbricht preparing the telescope and camera before the transit.

Sunday, March 9, 2014

The Chemical Furnace

Celestial Globe
Celestial globe, late 19th century.
This closeup image of a celestial globe shows an obsolete constellation called Machina Electrica (electrostatic generator) and Fornax Chemica (chemical furnace) which is now simply called Fornax. The latter constellation was originally named le Fourneau by La Caille in 1756 and was Latinized by him to Fornax Chimiæ in 1763. There are a variety of alternate spellings.