Just got my copy of Physics Today, and noticed that the cover looked familiar. It’s a drawing from a photo, depicting Simon Newcomb at the USNO’s 26″ telescope, and the article inside, Simon Newcomb, America’s first great astronomer, was co-written by a colleague. And it’s one of the free stories.

A complete account of Newcomb’s many achievements in astronomy, mathematics, physics, and economics is beyond the scope of this article. Indeed, the collection of his works held in the Library of Congress contains more than 46 000 items. We focus on Newcomb’s contributions to one of the central astronomical issues of his time: accurately determining the astronomical unit, the distance from Earth to the Sun. Newcomb did everything he could to ensure the success of massive American campaigns to better determine the astronomical unit by observing the transits of Venus in 1874 and 1882. Yet he also set out independently on a different path to reach the same goal. Ultimately, he succeeded in deriving a more accurate value sooner, at a tiny fraction of the cost, and without leaving Washington.

(I got to see the transit of Venus in 2004, with one of the views being through one of the telescopes that has been used to observe these 19th century transits)