Historical Section meeting 2020

The 2020 BAA Historical Section Meeting was an online webinar on the 21st November. This was in lieu of the scheduled meeting at the Birmingham & Midland Institute, Birmingham which could not be held due to the Coronavirus pandemic.

The meeting started at 14:30, with around seventy participants following live on the Zoom platform and the BAA’s YouTube channel.

Our speaker:

Dr. Geoff Belknap The Early History of Astrophotography

Section Director Mike Frost introduced Dr. Belknap who is Head Curator of the National Science and Media Museum, Bradford to give his presentation.

Geoff started by outlining the differences between photography and other processes of visual recording such as drawing, painting and litho and woodcut printing. Chemical photography had one great advantage in objectivity as it required no human interpretation in the production of a visual record. The pioneer in this field was William Henry Fox-Talbot (1800-1877) who recorded a latticed window at his home, Lacock Abbey in Wiltshire in August 1835. His work was followed a few years later by John Herschel (1792-1871) who imaged his father’s ‘40 foot’ telescope shortly before it was dismantled in September 1839. Early photographic emulsions were frequently deposited on glass plates to record images.

Early workers not only made records of celestial object and events, but also made images of instruments as well.

John William Draper (1811-1882), in America made an image of the Moon 1840 using the Daguerreotype process. But in the U.K. by the 1850’s Frederick Scott-Archer (1813-1857) wet plate collodion process had taken over as it was a more ‘robust’ process although it still required the facilities of a ‘dark-room’ to be built into the camera.

In 1856 Charles Piazzi Smyth (1819-1900) made an expedition to Tenerife and demonstrated the clear air at mountain tops was advantageous to observation. By this time Fox Talbot had moved on to reproduction rather than pure photography, devising ‘Photolithic’ printing.

In 1860 a partial solar eclipse crossed northern Spain and Warren de la Rue (1815-1889) recorded it. His techniques were continued at Greenwich Observatory to produce daily records of the Solar surface at visual wavelengths. Techniques in solar spectroscopy were developed and details of the solar spectrum were recorded rather than simple disc images.

Photography was expected to play a critical role in recording the transit of Venus in 1874 at five identically equipped expedition sites across the World. However the expedition failed to produce any new insights due to insufficient images resolution. Pierre Jules Janssen (1824-1907) devised a photographic revolver in an attempt to record rapid changes.

By the beginning of the twentieth century photography moved into other fields of scientific recording, while the astronomical community became bogged down in the international Carte du Ciel project which set out to record the whole of the night sky photographically. In astronomy scientific progress allowed photography to operate at wavelengths beyond the visual spectrum.

In recent years the historical value of old records has been realised and projects such as the Digital Access to a Sky Century @ Harvard have made images available.

Having completed his presentation, Dr. Belknap took a dozen questions from the audience. Mike Frost then thanked Dr. Belknap for his presentation, the audience for attending and Andy Wilson for managing Zoom and YouTube.

The meeting adjourned at 15:45.

An edited version of this event is available on the BAA’s YouTube Channel

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