The partial eclipse was observed using an old brass 4" refractor and Herschel
wedge solar / star diagonal loaned to me by the Manchester Astronomical Society.
The instrument has been adapted specifically to undertake solar photography.
The brilliant reflection from the front surface of the Herschel prism, even at
3% reflectivity, was attenuated by the incorporation of a polarising filter and
a neutral density ND 2.0 filter placed about 1" inside prime focus of the telescope.
The telescope is mounted on a spar-type equatorial mount made by the late Mr John
Rustige, an MAS member and very active contributor to the Solar Section of the
British Astronomical Association. John was a retired engineer and built his
equipment to be functional rather than aesthetic. Used with the solar diagonal,
the mounting allows comfortable, seated observations to be made. The picture
shows the set-up. The mounting is designed to be very robust but to allow
declination movement only within the limits needed to observe the Sun from Manchester
(53.5 N). It could also be used for lunar observations.
I had hoped that the optical set-up would allow sunspot photos but as it turned out
there were no surface details visible that day. Clouds did interfere but I got about
twenty slides, at about 5 minute intervals, taken on Kodachrome 200, with between
1/500 and 1/60 sec. These were automatic exposures with my Pentax ME Super camera body.
I have photographed several partial and two total solar eclipses with telephoto lenses
on a similar set-up so most of my pictures were rather routine. However, as the moon's
disk encroached onto the sun, a large crater was clearly seen in profile. This was
observed directly through the telescope as well as photographically. The seeing was
not good but one image was reasonably steady, as can be seen from the smooth solar limb,
and this shows the crater profile quite well. Even a central peak is visible. Please
look at the pictures.
To be seen in such profile, the crater has to be near the Moon's south pole.
It is also big, perhaps 150-200 miles in diameter. Can anyone identify it for me ?
What is the big plateau to its left ?
Kevin J Kilburn