630610Eclipse7_p1

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                      THE ROYAL ASTRONOMICAL SOCIETY OF CANADA
                   Standing Committee On Observational Activities
                    Programme for Solar Eclipse of Ju]y 20, 1963
                   ______________________________________________

Bulletin No. 7                                                          June 10, 1963

                                  SPECIAL PROJECTS


    Since the National Eclipse Committee began issuing this series of bulletins as a
guide for those who intend to observe the forthcoming solar eclipse, a number 
individuals have written describing more advanced or specialized projects which the
intend to carty out. In addition, it was realized while the other bulletins were
being prepared that certain of the programmes described should receive more elaborate
treatment than was then possible. The purpose of this bulletin is to provide a
more detailed description of some aspects of the proposed observation programme.

    The list of projects herein is probably not complete. Hence we would be
interested to hear of arv other special projects which are being contemplated. If
arwone still firS the information in this bulletin inadequate, he is invited to write
to the co-ordinator for further information.


1.  The Committee would like to draw attention to the directions in Bulletin No.3 for
    observing the flash spectrum with a diffraction grating and binoculars or a tele-
    scope. Transmission gratings aflai most of the incident light to pass through
    in a "white" beam. This beam must be avoided as it will injure the eye. The
    spectrum emerges fran the grating at a fairly wide angle to this beam, and this
    angle can be best found experimentally by placing the grating over the objective
    and projecting the image onto a white card. When the spectrum emerges straight
    cut behind the eyepiece, the white beam should not be visible at all. For
    maximum safety the instrument should be mounted so that it will not accidentally
    be aimed at the sun when the observer looks in.

2.  Since Bulletin No.4 was published, Kodak has issued a revised booklet on solar
    eclipse photograjfty. Although substantially the same in most respects as the
    Original edition, it contains the following points which are worth mentioning:

    (1)  Neutral density PHOTOGRAPHIC filters are not suitable for visual use,
         since they transmit infrared rays which can burn the eye.

    (2)  When preparing to photograph the corona, bear in mind that Kodachrome II
         has a speed of ASA 25, raised from 10, and Tri-X pan film is now rated
         at 400 instead of 200.

    (3)  The following section of the exposure table needs to be revised as noted:

                 FILM                INNER CORONA             OUTER CORONA

                                 old            new          old          new

            Tri-X             f/8 @ 1/10    f/16 @ 1/10   f/8 @ 1/2   f/16 @ 1/2
            Roy. Pan              "         f/11 @ 1/10       "       f/11 @ 1/2
            High Speed
             Ektach.              "              "            "            "