truss dobsonian?

Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or a truss Dobsonian is a possibility.
Bruce

On Sat, 15 Mar 2008 17:00:46 -0700 (PDT), brucegooglegroups
wrote:

Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or a truss Dobsonian is a possibility.

They are often lighter, and they break down smaller than solid tube
Dobs. Mirrors may cool faster, and tube current effects are small. On
the negative side, they can be more prone to dewing, and they can have
more issues with stray light (both are fairly easily dealt with). If
they are not well designed and well fabricated, they may have issues
with collimation shifting with position. Again, though, that's not
commonly a problem.
_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

On Mar 15, 6:00*pm, brucegooglegroups wrote:

Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. *Or a truss Dobsonian is a possibility.

The first advantage of a truss Dob that comes to mind is portability
-- especially in larger (than 10-inch) apertures. A related advantage
is the weight the owner will have to carry. When I carry out my 80
pound, 12-inch truss Dob (which I did a few nights ago) I do so in
several, separate trips. IIRC, the heaviest single component of my 12-
inch is about 36 pounds. Some people avoid lifting much weight via
the use of wheeled handcarts.

For 10-inch and smaller apertures the portability and weight
advantages are 'borderline'. Often a 10-inch or smaller Dob is
manageable enough and transportable enough without resorting to a
truss assembly. For some people even a 12-inch, solid-tube Dob is
manageable enough. Appropriate storage of the telescope (regardless
of the design) will have to be worked out in a manner that provides
adequate protection for the optics.

Most owners of truss Dobs cover the truss assembly with some form of
dark material to block light and/or to minimize dew and frost
formation on the mirrors -- yet more work when one wants to use the
telescope. Truss Dobs tend to need re-collimated prior to each use.
Yet, depending upon how well designed the scope and accessories are,
set-up and take-down *can* become a relatively quick and easy
routine.

All things considered, *if* a truss design is necessary in order to
meet your current or future portability requirements -- then a truss
Dob is the logical choice. Otherwise, a solid tube is likely to be
more practical.

Bill Greer
To sketch is to see.

On Mar 15, 10:15 pm, wrote:
On Mar 15, 6:00 pm, brucegooglegroups wrote:

Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or a truss Dobsonian is a possibility.

The first advantage of a truss Dob that comes to mind is portability
-- especially in larger (than 10-inch) apertures. A related advantage
is the weight the owner will have to carry. When I carry out my 80
pound, 12-inch truss Dob (which I did a few nights ago) I do so in
several, separate trips. IIRC, the heaviest single component of my 12-
inch is about 36 pounds. Some people avoid lifting much weight via
the use of wheeled handcarts.

For 10-inch and smaller apertures the portability and weight
advantages are 'borderline'. Often a 10-inch or smaller Dob is
manageable enough and transportable enough without resorting to a
truss assembly. For some people even a 12-inch, solid-tube Dob is
manageable enough. Appropriate storage of the telescope (regardless
of the design) will have to be worked out in a manner that provides
adequate protection for the optics.

Most owners of truss Dobs cover the truss assembly with some form of
dark material to block light and/or to minimize dew and frost
formation on the mirrors -- yet more work when one wants to use the
telescope. Truss Dobs tend to need re-collimated prior to each use.
Yet, depending upon how well designed the scope and accessories are,
set-up and take-down *can* become a relatively quick and easy
routine.

All things considered, *if* a truss design is necessary in order to
meet your current or future portability requirements -- then a truss
Dob is the logical choice. Otherwise, a solid tube is likely to be
more practical.

Bill Greer
To sketch is to see.

Hi Bill,
I am looking at a 10inch. At this size, the solid tube will be more
practical.
I am also thinking a buying a shed to store it outside. Comments on
this?
Bruce

After going through 5 other telescopes of various configurations and prices,
the 10"
Dob I bought from Orion is by far the best one. Exceptional optics and the
tube with
soft case easily fits in the trunk of my '71 Mustang along with camping
gear. The base
is the ~size of a child's car seat.


"brucegooglegroups" wrote in message
...
Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or a truss Dobsonian is a possibility.
Bruce

Careful of the refractor Gods, they may retaliate.


Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or a truss Dobsonian is a possibility.
Bruce

On Mar 16, 8:08*am, brucegooglegroups wrote:

I am also thinking a buying a shed to store it outside. Comments on
this?

A shed can be used advantageously. When stored outside a telescope
tends to be more accessable for use and closer to the temperature of
the outside air. Also, with limited (or no) transport distances, the
collimation is more likely to maintain itself.

There are different concerns in different regions. For myself, dust,
bugs and rodents were a concern with my roll-off-roof observatory. At
the end of an observing session (after I was certain that any dew or
frost had evaporated -- which sometimes meant waiting until the
following afternoon) I would make certain that all openings in the
optical tube assembly (OTA) were sealed or tightly covered. Even the
smallest screw hole should be sealed. Some bugs are very tiny and
capable of multiplying once they get inside! Besides, I try to do
everything possible to minimize the accumulation of dust on my
optics. The less often an optic needs to be clean -- the less likely
it will be damaged. My final step consisted of covering the OTA with
a tarp that I had duct-taped into the proper shape.

You won't *have to* use the same routine as I outlined above. Just
use common sense. When you notice a problem, take steps to fix it so
that particular problem is never a problem again. For the first year
make frequent inspections to make certain that your own protection
scheme is working. After that, you should be able to rest more
comfortably knowing that your telescope will be ready to go to work
when you are.

Bill Greer
To sketch is to see.

On Mar 16, 11:10 am, "goodnigh" wrote:
After going through 5 other telescopes of various configurations and prices,
the 10"
Dob I bought from Orion is by far the best one. Exceptional optics and the
tube with
soft case easily fits in the trunk of my '71 Mustang along with camping
gear. The base
is the ~size of a child's car seat.

"brucegooglegroups" wrote in message

...

Any advantage to a truss Dobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or a truss Dobsonian is a possibility.
Bruce

Hi,
Have you tried Orion's 8inch Dob, and how does it compare? I toying
with the idea of buying an intelliscope, and I will borrow a 10 inch
from my astronomy club. But I am adept enough at reading star charts
not to need the digital setting circles.
Bruce

On Mar 16, 11:10 am, "goodnigh" wrote:
After going through 5 other telescopes of various configurations and prices,
the 10"DobI bought from Orion is by far the best one. Exceptional optics and the
tube with
soft case easily fits in the trunk of my '71 Mustang along with camping
gear. The base
is the ~size of a child's car seat.

"brucegooglegroups" wrote in message

...

Any advantage to atrussDobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or atrussDobsonian is a possibility.
Bruce

Is your Dob an intelliscope or a classic?
Bruce

"brucegooglegroups" wrote in message
...
On Mar 16, 11:10 am, "goodnigh" wrote:
After going through 5 other telescopes of various configurations and
prices,
the 10"DobI bought from Orion is by far the best one. Exceptional optics
and the
tube with
soft case easily fits in the trunk of my '71 Mustang along with camping
gear. The base
is the ~size of a child's car seat.

"brucegooglegroups" wrote in message

...

Any advantage to atrussDobsonian? I am thinking of buying a 10 inch
Dob- perhaps an Orion. Or atrussDobsonian is a possibility.
Bruce

Is your Dob an intelliscope or a classic?
Bruce

Intelliscope, although I have never used that feature.
You must buy the Intelliscope ready model even if you don't
buy the computer. You can always buy the computer later.
A friend and I built a green laser pointer that emanates from the finder
scope.
You point the laser where you want to look and the object
is in the main scope's eyepiece. This setup has proven to be more useful.

mike