On 17 July 1850, astrophotography was taking its well-deserved place in the history of human progress. On 17 July 1850, the first photograph of a star other than our Sun was taken. It was Vega, a star which means so much to astronomy and to us. So this week, the week we relish the sight of the comet NEOWISE and capture spectacular images, take some time and think about this major achievement. Indeed a predictable achievement, but one that took us one step closer to the stars. One step closer to the vastness that is the Universe.
In fact, astrophotography began somewhere in 1840, when John William Draper took an image of the Moon, using a technique called daguerreotype. It was based on polishing a sheet of silver-plated copper to a mirror finish, treating it with fumes that made its surface sensitive to light and exposing it in a camera for as long as it was necessary.
The first photo of Vega was also taken using this technique. The exposure time was 20 minutes. So on July 17, 1850, William Bond and John Adams Whipple imaged Vega. John Adams Whipple was a photographer and American inventor, completely unrelated to astronomy, and William Bond was the first director of the Harvard Observatory. The telescope in the picture is a 15-inch (38 cm) refractor.
But What Is Vega?
Maybe the first thing that comes in your mind when thinking about Vega is its constellation, Lyra. Indeed, it is the brightest star in the Lyra constellation (or the alpha star). Also, it is the fifth in the ranking of most brightening stars. The star is also relatively close to us, at only 25 light-years from Earth, and really young: Vega is just 450 million years old.
An important thing about Vega is that it is considered by astronomers as a baseline in
calibrating the photometric scale, and its apparent magnitude can be considered 0. Astronomers consider it “arguably the most important in the sky after the Sun”, as it is one of the most extensively studied stars. Vega also came into the pop culture, with the movie “Contact”, based on the famous Carl Sagan story. In the movie, Vega is the point where extraterrestrial signals seemed to come to Earth.
So photographing Vega was a major milestone, indeed.
There Was More About Vega In 19th Century
Now there is something more about Vega. A milestone of equal importance to that of
photographing the star. Besides being the first star other than the Sun to be photographed, Vega is also the first star to have its spectrum recorded. Henry Draper, the famous astronomer took the first photo of Vega’s spectrum in August 1872, and he became the first person to show absorption lines in the spectrum of a star.
William Huggins used all of the data in 1879, of Vega and a few other stars to identify a set of “very strong lines”. They were later identified as the lines of the Balmer series. So identifying Vega’s spectrum was very important, as it became one of the standard points from where classifications are made.