Editing Samuel Langley (section)

==Allegheny Observatory==
Langley arrived in Pittsburgh in 1867 to become the first director of the Allegheny Observatory, after the institution had fallen into hard times and been given to the Western University of Pennsylvania. By then, the department was in disarray – equipment was broken, there was no library and the building needed repairs. Through the friendship and aid of [[William Thaw Sr.]], a Pittsburgh industrial leader, Langley was able to improve the observatory equipment and build additional apparatuses. One of the new instruments was a small transit telescope used to observe the position of the stars as they cross the celestial meridian.<ref>[http://www.pitt.edu/~aobsvtry/history.html University of Pittsburgh history]</ref>

He raised money for the department in large part by distributing standard time to cities and railroads. Up until then, correct time had only occasionally been sent from American observatories for public use. Clocks were manually wound in those days and time tended to be imprecise. Exact time had not been especially necessary. It was enough to know that at noon the sun was at its highest elevation for the day. That changed with the arrival of railroads, which made the lack of standard time dangerous. Trains ran by a published schedule, but scheduling was chaotic. If the timepieces of an engineer and a switch operator differed by even a minute or two, trains could be on the same track at the same time and collide.

Using astronomical observations obtained from the new telescope, Langley devised a precise time standard, including time zones, that became known as the [[Standard time#North America|Allegheny Time System]]. Initially he distributed time signals to Allegheny city businesses and the [[Pennsylvania Railroad]]. Eventually, twice a day, the Allegheny time signals gave the correct time via 4,713 miles of telegraph lines to all railroads in the US and Canada.  Langley used the money from the railroads to finance the observatory.  From about 1868 revenues from Allegheny Time continued to fund the observatory, until the US Naval Observatory provided the signals via taxpayer funding in 1883.

Once funding was secure, Langley devoted his time at the Observatory initially in researching the sun. He used his draftsman skills—from his first job out of high school—to produce hundreds of drawings of solar phenomena, many of which were the first the world had seen. His remarkably detailed 1873 illustration of a sun spot, observed while using the observatory's 13-inch Fitz-Clark refractor became a classic. It is featured on page 21 of his book, ''The New Astronomy'', and was also widely reprinted in the Americas and Europe.

In 1886, Langley received the inaugural [[Henry Draper Medal]] from the [[United States National Academy of Sciences|National Academy of Sciences]] for his contributions to [[Sun|solar]] physics.<ref name=Draper>{{cite web|title=Henry Draper Medal|url=http://www.nasonline.org/about-nas/awards/henry-draper-medal.html|publisher=National Academy of Sciences|access-date=19 February 2011}}</ref> His publication in 1890 of infrared observations at the Allegheny Observatory in Pittsburgh together with [[Frank Washington Very]] along with the data he collected from his invention, the bolometer, was used by [[Svante Arrhenius]] to make the first calculations on the [[greenhouse effect]]. In 1898, Langley received the [[Prix Jules Janssen]], the highest award of the [[Société astronomique de France]] (the French astronomical society).