Hello Fellow Stargazers, and ATM'ers!
...and Welcome to the web pages covering the construction of the VSC's "SAO
Carton 100mm f/13 'Mary Dawson' Refractor". Though this refractor is smaller
in aperture as compared to the 127mm f/9.4 "BGRP" refractor I constructed
back in December, 2009, its optics are far superior. The instrument utilizes
a brand new vintage 1980 mounted Carton 100mm f/13 achromatic Fraunhofer
doublet, that is said to be the finest objective that Carton Optical Company
of Japan had ever produced. And I must say, that all of the hoopla about
these optics have held true in my experience.
After spending a great deal of time
with my SAO Surplus Shed 127mm f/9.4 "BGRP" refractor, I was well aware
that it was not the planetary instrument I was hoping for. Yes, it was
awesome from low to medium magnifications, but I longed to see greater
detail on those grand outer planets we amateurs love to gaze upon so much
through a refractor. From that fresh mindset, a new drive arose for me to
build a refractor for planetary and double-star use. In researching to
find adequate optics, I ran across a threads on Cloudy Nights that truly
sparked my interest immensely. It was start by Cloudy Nights member Doug76
regard the build of his Carton 100mm f/13. I followed along and partook in
his thread. I was pleased with Doug's comments to the point that I was
nearly pounced on a set of the optics immediately, but I wanted to do more
research before I committed to the build. The mounted Carton 100mm f/13
Fraunhofer achromatic objectives were being sold by Sheldon Faworski, an
affiliated of the now defunct Apogee, Inc. In my search I discovered a
wealth of knowledge about these lens from several resources, which
ultimately convinced me to purchase a set form Sheldon for $215.00. This
was a fantastic price considering how much the telescopes holding this
lens set was going for. The Italian based retailer "NortheK" was offer a
custom built Carton 100mm f/13 refractor OTA sporting a carbon fiber tube,
Crayford focuser, anodized components, and cradle rings with dovetail bar
for around $1800.00!!! A testament to the true quality of this fine
instrument. With that, I must say that I was not disappointed and was
sold. So, I made the investment. To make this a special memorial piece, I
named the scope after my dear mother, Mary Dawson, one of the main
catalysts for sustainability, growth, love and well-being within my life.
Now let's see how the VSC/ SAO Carton 100mm f/13 "Mary Dawson" refractor
came to be via this construction overview. I hope each and everyone that
reviews the contents of these pages will find inspiration to embark on
their own telescope project. Believe me when I say that it is one of the
most rewarding experiences of my life.
FIRST
LIGHT
REPORT
-- JULY
10, 2010
Hello Good Friends,
Thanks
to the prayers, strength, support of so many of you and God, I am happy to
announce that I was able to perform First Light with my Carton 100mm f/13
tonight!
As dusk came and the skies turned a deep teal blue at
around 9:00pm EDT, my first target with the "Mary Dawson" refractor was
Venus. Using a TeleVue 15mm Plossl, which yield a magnification of 87x, I
slowly focused Venus in the field of view and was very pleased at the
image I was seeing. Despite some purple fringing, Venus was very sharp and
CA was held very, very low even though Venus was low in the sky.
Typically, viewing objects that low in the sky would general tease out the
CA of many a celestial object. But, the instrument held this aberration to
an extreme minimum; impressive indeed! Enjoying the view, I moved up to a
TeleVue 11mm Plossl. This gave me a power of 118x. At this magnification I
could easily make out slight irregularities in the Venusian terminator of
its gibbous phase. That was quite a sight! It was the best view I have
ever seen through and refractor I have owned. Again, purple fringing was
present, but in no way was it an issue. CA was practically nonexistent.
Contrast was outstanding through the test.
Darkness settled in
good at about 10:00pm EDT, and it was time to check out some of those
DSO's and Double Stars! With my good friend Gary Barabino on the other end
of the phone, he suggested that I check out M13, the Hercules Cluster. The
globular cluster was approaching the meridian from my vantage point and
prime for viewing. I realize that the 100mm is not a light bucket; however
I wanted to see what it could do on DSO's. Bright globular clusters can
produce surprisingly beautiful images when put under moderate
magnification. It was no surprising in the Carton. M13 was resolved to the
core with ease at 87x with the TeleVue 11mm Plossl. At 118x with the
TeleVue 11mm, the core sparkled like diamonds. I only wish I was out at a
dark remote site to take it all in. The next DSO I chose to check out was
M57, the Ring Nebular. Why the Ring Nebula? Well, I wanted to see how well
the optics of this "four incher" would fair on an object that is generally
viewed with large aperture telescopes. Once again, I was quite impressed
with the image. The ghostly ring stood out even at 118x! Of course, seeing
the central star was impossible. Nevertheless, you could make out the
shape and some faint structure in the ring's nebulosity. I am really
digging this scope, man!
Around 10:45pm EDT, I decided to check
out a couple of brightest stars. First up was Arcturus. This star produced
a very tight disk with minimal flaring. Diffraction rings (two) were close
to the star's disk and the color was a pale orange. Only a little purple
fringing was discerned. Very nice image! Next up was Vega. Again tight
diffraction rings (two) and the color appeared a brilliant blue-white.
Purple fringing was a bit more prominent on Vega as compared to Arcturus,
but nothing to be upset over at all.
Moving on, it was time to
check out a double star, and the one of choice was Epsilon Lyrae, the
Double-Double. What really struck me was how tiny the disks of the stars
were. Also how tight the diffraction rings were in relation to the stars.
Simply amazing how small the airy disks were.
I wanted to check
out a few more objects, but I started to get a bit tired. So at around
11:30pm EDT, I called it a night. In conclusion, I could not have asked
for a better result after tonight's First Light session with my Carton
100mm f/13 "Mary Dawson" refractor. Total success was achieved! Doug is so
right to exonerate the attributes of this fine instrument the way he does.
It literally produces APO like image quality, but in a larger package.
However, an APO would never touch the magnification this lady could
produce. I am very pleased with this instrument and will be reporting back
with more observing session details in short order! If you want a
telescope in the 4” range, get yourself one of these objectives. I saved
plenty cash in building my own like many others here on this thread. But,
the optical results of this refractor are worthy of telescopes costing far
more.
At the top of this page is a shot of
me with my homebuilt Carton 100mm f/13 during the First Light session. My
mom would truly be proud of this instrument, which carries her name.
Sincerely, Mel Dawson
..."Clear Skies, Forever!"
