Transit of Venus by R Bray

[Harry Roberts]

Bob Bray is perhaps Australia's leading heliophysicist - with a great number of papers and books about the Sun. Here's his account of the history of the TOV.

http://articles.adsabs.harvard.edu/cgi- ... etype=.pdf

Bob's work with the Sydney five inch photoheliograph and later the 30cm Culgoora photoheliograph (Fig) produced extraordinary insights into the physics of our daytime star. The latter 'scope was a further development of innovations used on the "five inch", including a seeing monitor that enabled resolution better than an arc second to be achieved in photos made through a tunable 1/8 angstrom (ie 0.125A) Lyot filter with 1 angstrom pre-filter. Amazing for a 1968 telescope. Note the open truss and fork mount. Sunscreens shade the two counterweights, and perhaps the triangular sunscreen at the top is the hollow "sandwich" type first employed on the five inch in late 1950's (ref "Sunspots").
Key texts are "Sunspots" R. J. Bray and R. E. Loughhead, and "The Solar Chromosphere" by the same authors.