Circa 1983 we have an Edmund 6" f/15 achromat on a large alt-az mount. The rings are sections of 13" sewer pipe. This mount was contracted by the owner of the scope.
Telescopes big and small, good and poor, light and heavy, cheap and pricey.
Circa
1983 we have an Edmund 6" f/15 achromat on a large alt-az mount.
The rings are sections of 13" sewer pipe. This mount was
contracted by the owner of the scope.
From
about the same time, this is an AstroPhysics 6" f/8 apo. This
was one of the first 6" oil-spaced triplets, made from the
original batch of NASA glass. It was housed on an alt-az mount. One
of my most memorable observing experiences was looking at M13 at 600x
with this scope shortly after it arrived. There is not enough light
in a 6" to 'hold the images' at this magnification; instead the
mass of jewels that filled the view of the 9 mm Nagler twinkled. (To
get the high magnification, a 2" barlow was used with the 2"
star diagonal between the barlow and the eyepiece, effectively
multiplying the nominal power of the barlow by about 1.5).
In
1985 I made by first big Dob. It had a horrible 17.5" mirror
from a (thankfully, now) defunct firm at Salt Lake City. The
altitude bearings are plywood, cut with an Egyptian motif. The upper
cage is a piece of aluminum flashing spray painted black. The mirror
had 18 pt flotation and a sling. The scope was sold to a local
laboratory; I believe they replaced the optics. The highest
magnification the scope could handle was about 67x (with a 30 mm
Televue WideField), and it never showed stars fainter than mag 13.
At the right you can see part of the base on which the altaz mount for the AP-6 (above) sat.
Now
here is a mount. The fork arms of this Mathis-M11 are ½"
sand cast aluminum and each weighs more than the entirety of an LX200
mount. This mount has been modified and now is servo controlled,
with one declination bearing housing a 6" bronze worm. In this
view, the mount was driven by a 60Hz synchronous motor with a drive
corrector. The C11 tube is from about 1984.
Seen behind is the black tube of a 10" f/6 with a wonderful mirror made by Gerry Wilkinson.
Missing
part of one 'head' is a 12.5" f/5 binocular telescope. This
scope was active about 1990-2. The design was somewhat problematic;
you could adjust the collimation at the eyepiece, and it would hold
so long as you didn't move the scope. It was awkward to use, but
gave some great views, and amply demonstrated the benefits of
binocular vision. It is said that our vision system is
'common-mode', meaning that our brain tends to reject differential
signals (those that appear in one eye and not the other). I had this
scope out in the driveway with two 30 mm UltraScopic eyepieces giving
53x and a field just smaller than one degree. A neighbor came by and
asked for a look. Being an experimental sort of person, I removed
one eyepiece and showed her M13. "What's that? -- it looks like
cotton candy" Then I put in the other eyepiece. "Whoa",
she said, "its made of stars!".
Over-mounted?
No way. Here is an early Vixen/Celestron C102F 4" fluorite on
the Mathis mount. That's right, an 8 lb telescope on a 250 lb
mounting. This telescope, which I still have (the picture is from
about 1984) deserves any mount you put it on. It is the 900 mm FL
model, and it is magnificent. At f/9, the images are best I have
ever seen (Takahashi and A-P not withstanding). During the
occultation of 22 Sgr (?) in 1986(? - I should check these), I had
this mount in the Santa Cruz mountains with the C11 tube. The C102F
was relegated to being propped up on the deck railing. You could see
the star 'merge' into the rings as it moved behind them in the C11.
In the C102F, the star popped in and out as clearly as "night
and day". After that, the fluorite got to use the mount, as
shown here.