670228Instrumentation2

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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.