Observing under a street lamp
10/22/00
by Michelle
Stone
Last night, I took out mama's new baby, a Televue SDF 101mm refractor. The
scope is not new. They are no longer manufactured. The scope was sold as a
fluorite apo in its day. I've heard that these scopes do not perform as well as
the AP and Takahashi models in terms of color correction, but I wanted one. And
it is my birthday this month so Paul wanted to make sure I got a nice present.
This year, I really didn't mind selecting my present ;)
I love Televue instruments. Everything is machine made to strict tolerance.
The focuser has a velvet action and the dewshield slides silently to it's
extended position. I was anxious to get set up for some Thursday night viewing.
My problem is that I live in the middle of Silicon Valley. I rarely can see
more than a dozen stars or so in the sky due to the severe light polution. In
addition, I have virtually no sky in the back or side yards that are not
obstructed. The only location in the yard that has access to the sky is in
front, under a street light.
I rarely view from this location but a new scope must have stars to eat. So
out I went. I set it up on a Celestron C5 mount, a clone of the Vixen Polaris
mount. It took me a few short seconds to realize this mount isn't enough to
adequately hold the scope to my liking. Oh it supports it well enough, it's just
that I'm very accustomed to a very steady mount for viewing. The scope is not
long but it is substantial for its size. Even with hardwood legs, the shaking
through the eyepiece was at best annoying. Once settled out however, it
performed quite well. I think that this will be going on my G11 mount most of
the time I use it. I must note here, that most people would argue the G11 is way
too much mount for a small scope this size and that the GP should be fine. I
prefer rock solid stability.
Seeing conditions were remarkably good last nigt. The air seemed steady and
the transparency was not too bad. I spent some time on easy open clusters. I
know where they are relative to my trees... so yes, I was tree hopping to find
objects. The scope has a short focal length so with a large eyepiece, it serves
quite well as it's own finder. Stars were crisp and well defined. What I would
expect from a fine refractor. I popped over to Vega. There was a slight blue
haze around the star. Not perfect color correction but still not objectionable.
Well within expectations.
The double double was an easy clean split. The stars were beautiful pinpoints
of light.
Saturn was up so I popped over for a look see. This was a very nice view for
a small telescope. Excellent detail in the bands of the planet and rings.
Although still low on the horizon, the image seemed fairly sharp and well
defined. A hint of false color was visible.
While out, I decided to compare my Vixen Lanthunum 5mm Eyepiece with the new
Vixen Widefield 5mm. The new Widefield is a much larger eyepiece. It's apparent
field of view is 65 degrees as compared to the 50 degrees with the standard
Vixen. I could tell no difference in image quality or contrast with either
eyepiece on stars or on Saturn. I prefer the wide field however. I was using my
mount without motorized tracking and it seemed that I had to update my RA much
too often. The wider field afforded me the luxury of waiting and spending more
time.
My first looks at Jupiter were through the trees. The image was not good due
to the obstruction. It later disappeared behind a power pole. I went inside to
do some work while the planets got a little higher. I came back out around 11 PM
and it had totally clouded over. I took down and put everything away. It cleared
up.
As far as the street lamp goes... New toys don't care much their first time
out ;)
