6755third light - ZSFD
- Jan 4, 2006Hi All,
This is a rambling, casual third light report, for my new WO ZSFD red
scope. Twice before tonight I was able to find time on clearish nights
to gaze upward, but only for about 10 minutes each time due to the sky
becoming cloudy and family obligations during the holiday evenings.
The new scope is my first "real" (well, "real good") telescope, the
prior one being a cheap refractor owned as a kid. I don't remember
seeing anything but the moon through that one. It is long lost and
forgotten. My observation skills are not developed! And, so, I won't
try to give any detailed analysis of the optics, etc. Just what
equipment I used, what I saw, and some ideas I have about optical issues.
Tonight, here in my urban backyard in Raleigh, NC, skies haven't been
fantastic for viewing. (Clear skies since the scope arrived have been
exceedlying rare, as expected.) I just came inside, around quarter
till 1AM. The clear sky clock lists transparency as too cloudy to
forecast, and bad seeing, with only occasional pockets that aren't
covered by clouds. And that prediction seems consistent with what I
experienced. But, I was able to see what I wanted to see!
I didn't expect an opportunity to observe. But, about 2 hours ago I
poked my head out and saw a few stars. Enough clear spots that I
thought I might be able to spot Saturn. And so I set the scope up. I
spent about an hour observing, only occasionally steering away from
Saturn (which I guess is the "star" of the skies this month).
Equipment was the ZSFD red scope, a Stellarvue M1 alt-azimuth mount on
a Manfrotto 3021 pro tripod, a WO 6x30 finder scope, and 3 eyepieces:
a 25mm WO SWAN, a 12.5mm Celestron X-Cel, and a 4mm Burgess Planetary
eyepiece. Oh, and a wrought iron lawn chair, brought into service when
I got tired of sitting on my knees.
I am not finding the finder scope to be terribly useful. I have found
that I have difficulty mounting it to the scope securely enough that
it stays aligned. A small locking/alignment pin for the finder mount
would be an *extremely* welcome feature (really, I mean it). The
finder has helped a bit, but I have also found it awkward to peer
through. I'm thinking a red dot finder may be a bit nicer, but when I
ordered the scope I was looking for a more traditional-looking finder
scope. Perhaps I don't even need a finder scope, and can simply use
the 25mm SWAN for locating objects. Oh well, I am learning.
I am somewhat familiar with the Orion complex, and was able to use
Betelgeuse as a starting point to find Saturn (once it rose above the
mature pine trees in my back yard).
The 25mm WO eyepiece is very nice, in my opinion. Well made, to be
sure. Wide angle, very bright and (to my eyes) sharp views. It is big
(but, I'm guessing, not as big as a similar Nagler?). In this
eyepiece, @ 22x, Saturn looked kind of like a smudged star. I was not
able to distinguish the rings. I suspect that I might be able to
distinguish the rings in dark skies with better seeing and a more
stable mount (more on the latter later).
With the 12.5mm Celestron, @ 44x, the planet was a bit larger, and
only slightly dimmer. Here, I was able to separate the rings from the
disk, but only by carefully allowing the vibrations to settle. This
was tedious. I had to be sure to hold my head away from the eyepiece
to avoid exciting another vibration. This was the first time in my
life that I have seen Saturn live in person, and it won't surprise you
that I found it breathtaking.
With the 4mm Burgess eyepiece, @ 138x, the planet was larger still (no
duh!), and noticeably dimmer. But still quite bright. Again, I had to
wait for the vibrations to settle, but because of the enlargement I
actually found it easier to hold on to the visual separation between
disk and rings. Even with quite a bit of vibration during settling, I
never lost my hold on the separation.
I was unable to detect any ring divisions. I don't think this is too
surprising. It is only a 3 inch scope. Transparency and seeing were
not particularly good. And, skies here are not particularly dark. With
the 4mm Burgess, I was unable to achieve a tack sharp focus on Saturn.
That could have been due to seeing, etc. I also was unable to achieve
a tack sharp focus on stars with the 4mm, but was with the other two
eyepieces. Which, I believe, suggests that the distance from primary
to eyepiece might not have been sufficient. At this point, I believe
the objective lens was beginning to fog up a bit, and that too could
have caused perceived focus problems. Next time, I think I'll try to
lock the eyepiece in place slightly above its well-seated position, to
see if I can achieve better focus. Still, the focus I achieved on
Saturn was about what I expected, based on various astronomy books
I've been reading. The planet was bright enough and large enough that
I think it might be possible to detect (if only by averted vision) the
Cassini division at a dark site with good seeing through the 4mm.
I was not able to really detect any surface features on the disk.
Again, I don't think this is too surprising. The planet was large
enough and bright enough that I might see something at a dark site, or
with more practice observing.
I am learning a few things here. Things that I've read about, but
haven't experience first-hand until now. My house is located
prominantly at the front of the main drag through the neighborhood.
Its a show home spot. There are street lights up front. I have 1/4
acre lot, with mostly front yard. We like trees here. Big ones. I
decided to set up in back, since the back yard is more in shadow from
the street lights. But, the trees are all 50+ foot pines. And the back
yard is small. And, there is a deck. If I set the scope up in the
yard, I would only be able to see things at zenith. The deck gets in
the way. So, I decided to set the scope up on the deck, to have a
wider altitude range. With the combination of: a) the scope on a
wooden deck; b) Manfrotto tripod holding its absolute max weight limit
(actually a bit more); and, c) tripod center-post extended about half
way to enable the mount to look close to zenith, I found that I had
quite an unstable setup. Very little risk of the tripod toppling over,
but we're talking 10 seconds (TEN seconds) for vibrations to settle. I
believe that is quite poor! The scope was balanced fairly well on the
mount. But the M1 mount doesn't seem to have a mechanism to support a
counterweight on the other side. That could be an issue, I think. Some
similarly-styled alt-azimuth mounts provide a way to add a
counterweight bar... For those who want details, I had only extended
one set of tripod leg segments, and those were extended fully. And, as
mentioned above, the center post was half way up. In this
configuration, I found observing to be extremely comfortable in the
lawn chair for objects near zenith. Without the chair, I was on my
knees. For objects nearer the horizon, it was comfortable enough to stand.
About the Stellarvue mount...I will try to post more about over @
Cloudy Nights, in the Mounts forum, soon. I'll also try to find time
to take some photos and put up on my web site (www.gsrhodes.com), on
the telescope page. For now, I will just say that it is very well
made, appears sturdy and capable of holding the scope stably. I do not
have any real belief that a counterweight would help with stability in
my setup. I believe my stability issues arise from the tripod and deck
far moreso than the mount. That is not to say that I don't have some
(extremely minor) issues with the mount. I won't say more about this
until I've had time to take some photos and think about it further.
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