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THE ROYAL ASTRONOMICAL SOCIETY OF CANADA Bulletin No. 2 INSTRUMENTATION SECTION The response frcn Bulletin No.1 has been disappointing; possibly it takes a while to get rolling. Information can only be passed on through the Bulletin if it is first received. As suggested earlier, if each Centre would appoint a member to keep me informed, I will see that the material submitted is printed. Not all the information fran each Centre will be used in any one Bulletin; excerpts will be selected so that as many Centres as possible can be represented. The rest of the material will be filed and used later. Mr. Henri Simard, supervisor of the optics and instrument section of the Centre d'Astronomie de Montreal reports that in the latter part of 1966, forty members were constructing telescopes and about the same number will start telescopes in 1967. He also stated that he thought this Bulletin could been very important. Mr. D.J. FitzGerald reported for the Toronto Centre. He and Mr. Archie Ostrander have each constructed an 8-inch Richest Field telescope. Mr. Ostrander's is an F3.9 and Mr. FitzGerald's is F4.5. These feature tubes that are sealed with plate glass windars. A hole was drilled through the centre of the plate and the diagonal attached directly across it. This removed the conventional spider and spider diffraction. Star images appear more like those in a refractor. Air currents in the tube are practically eliminated and the optical surfaces remain cleaner with the life of the reflective coatings extended. Mr. FitzGerald explained their method of testing the glass plates. Libby Owens Ford Twin Ground plate was found most suitable. The glass was subjected to an exhaustive bench test by setting it up immediately in front of the main mirror and observing with a Foucault tester and a Ronchi ruling. Although the light had to pass through the glass twice, they could not notice any diffrrence in the appearance of the lines when the plate glass was in or out of the optical path. Apparently one piece of this glass had to be rejected; another make of glass with a better appearing surface finish proved unsuitable when tested. The University of Victoria is presently having a new 12-inch Tinsley reflector installed in the 16-foot steel dome on the roof of the four storey Science Building. Through the generosity of the tJniversiiaj the Victoria Centre had their U-inch refractor mounted in this dane for the past two years. A roll-off roof enclosure on the sane building will now be used for this. Would all the Centres intending to participate in the display at the 1967 General Assembly in Montreal please advise their Presidents as soon as possible. Pictures from all Centres would be welcaned for the exhibit on astrophotography, equipment, amateur observatories at any stage, star parties and group observing. Ccnplete information should be included so that your Centre or an individual may receive full credit. George R. Ball, National Co-ordinator, Instrumentation Section, Standing Committee on Observational Activities, 54 West Naddock Ave., 28 February, 1967. Victoria, B.C.