Re: Opinions on Meade truss-tube Dob?
- From: Willie R. Meghar <NoMail@xxxxxxxxxxxxxxx>
- Date: Mon, 20 Nov 2006 20:21:22 -0700
"Rune Allnor" <allnor@xxxxxxxxxxxx> wrote:
Is this scope worth considering?
If you're interested in a portable Dob of 8 to 12 inch aperture at an
affordable price I would say; "Yes!"
What about the optics?
I've used the 12" on two nights so far.
For deep sky use the 12 inch optics are excellent. I've viewed DSOs
(and examined star images) at magnifications up to 245x with good
results.
For planetary use: I don't know; but based on observations on a
rising Saturn, the view continued to improve as the planet climbed
higher in the sky. I felt the scope could have handled more
magnification than was used (155x); but the structure the scope/mount
was set up on wasn't stable enough. (Planetary observation wasn't
planned for on that night!)
The included 2" 26mm QX eyepiece performed very poorly compared to a
2" 27mm Panoptic. The QX had *much* poorer performance as one shifted
one's view away from the field center. The scope cries out for better
eyepieces!
Mechanics?
I would give excellent marks to the optical tube assembly.
Collimation changes "a little" upon disassembly and re-assembly; but
the overall design is well thought out and well executed.
The edge-laminate within the recess in the mount for one altitude
trunnion (in the scope I used) was not glued adequately; but the
weight of the scope pressed it into place. If necessary, such defects
can be corrected by the owner.
Don't plan on setting the OTA (off the mount) onto its tail bone. The
Collimation and/or locking screws can stick out far enough that you'll
be resting the OTA's entire weight on the screws!
The "hand holds" at the bottom of the fork tines were not laminated.
It was necessary to remove a small roller-bearing from the azimuth
bolt in order for the bottom of the OTA to clear the top of the
azimuth bolt. The absence of that bearing had absolutely no other
effect on the performance of the mount The bolt did *not* turn (loosen
or tighten) when the scope was moved in azimuth.
It's advisable to install the eyepiece tray "upside-down". Otherwise
the alt. brake blocks the use of one of the holes.
Storage?
The base for the 12" is about 25" in diameter. The assembled OTA is
56 to 57" in length; but there's no need to store the OTA assembled.
Handling?
The deluxe version moves a bit easier than I would like in azimuth;
but it's perfectly manageable. The "stiction" in altitude has a nice
feel to it. There was no need to use the alt. break when swapping
between (not overly heavy) 2" and 1.25" eyepieces.
The mount and the lower section of the OTA each require two hands to
carry. A third hand and arm would be handy to open and close doors!
IIRC, the lower OTA section weighs about 36 pounds; and the mount
weighs about 33 lbs. Those are the heaviest, single components. The
total weight of the telescope and mount is about 80 lbs.
You'll want a shroud to cover the truss assembly (prevents or
substantially delays dew and frost from forming on the mirrors) It's
easy enough to make a good, inexpensive, home-made one. Otherwise
more than one version is available commercially. (I can't speak for
those!)
Willie R. Meghar
.
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