Which Is the Better Deep-Sky Telescope?

Without a doubt more aperture is better, all other things being equal, when
it comes to deep sky objects. The 127mm is a fine telescope; I own one.
But I also don't use it for deep sky, visual or imaging. The 10-inch is
over 4 times the light capture area of the 127mm, again everything else
being equal, and that means significantly brighter views of deep sky stuff.

--
Yours Truly,
--- Dave

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'raid if you're afraid you'll have to overlook it.
Besides, you knew the job was dangerous when you took it.
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"Dave Mitsky" wrote in message
om...
I'd like to hear your opinions on whether a 127mm Orion
Maksutov-Cassegrain is a better deep-sky telescope than a 10" Orion or
Hardin Dob that is now on sale for about the same price. Don't laugh I
have a very good reason for collecting this information.

Dave Mitsky

For visual use on deep sky objects, all other things being equal, IMO
the 10" Newtonians would be better than the 127mm Mak-cass.

1) The 10s collect more light and concentrate more light into the
image of any given deep sky object. Small, faint DSOs would appear
brighter with the 10s. More stars would be visible in star clusters.

2) The 10s have shorter focal lengths. This translates into the
possibility of achieving wider true fields of view with the 10s. As a
result the 10s would be superior to the 127 for viewing large DSOs.
(The option of using 2" O.D. eyepieces will also be beneficial.)

3) Assuming reasonably well-designed and well-built mounts, it would
be possible to beneficially use higher magnifications with the 10s.
This would make visible smaller and fainter DSOs. This will also
reveal greater detail in DSOs.

The 127 also has some advantages: It's a more compact telescope.
Motorized tracking is convenient. Some observers enjoy the challenge
of undertaking deep sky work with smaller apertures. Eyepiece
location wouldn't change as much. The 127 would be easier to
configure for non-visual use.

The longer focal length of the 127 would not be a disadvantage for
small DSOs or for using high magnifications.

Still, if the bottom line is the view in the eyepiece the 10s hold a
very definite advantage for large as well as small deep sky objects,
for fuzzy DSOs as well as for open and globular star clusters.

If compact size is critically important, if a person simply enjoys the
challenges associated with using a smaller telescope, if there's a
willingness to sacrifice large fields of view, or if motorized
tracking is very important for someone then the 127 Mak-cass. *can* be
effectively used for quite a bit of deep sky work. Just don't expect
the eyepiece view with the smaller Mak-cass. to equal or surpass that
of a 10 inch Newtonian. The 10 inch will show *all* deep sky objects
better.

Sketcher
To sketch is to see.

(Bill Kocken) wrote in message . com...
Sorry, I'm laughing.. I hope you'll tell us why you're asking.
The 10" by far. Only possible reasons to choose the 127mm are
portability or ability to put it on an equatorial mount.
Bill Kocken

I'd like to hear your opinions on whether a 127mm Orion
Maksutov-Cassegrain is a better deep-sky telescope than a 10" Orion or
Hardin Dob that is now on sale for about the same price. Don't laugh I
have a very good reason for collecting this information.

Dave Mitsky

I asked to prove a point to someone who has insulted me repeatedly on
another forum when I informed him that his newly purchased Orion 127mm
f/12.1 MCT was perhaps not the best choice as a deep-sky telescope.
This was in response to a query that he himself posted. This fellow
seemed to think because he could see some of the showcase Messier
objects with the Mak that aperture was irrelevant. He's got very
strong opinions for someone who's only been observing for a few months
and didn't know how to locate M31.

Dave Mitsky

I asked to prove a point to someone who has insulted me repeatedly on
another forum when I informed him that his newly purchased Orion 127mm
f/12.1 MCT was perhaps not the best choice as a deep-sky telescope.

Dave:

I hope the fellow in question has been following this thread.

As Rod says, "There are no bad telescopes" and I agree to a large extent. But
it is also clear that a 10 inch F5 DOB will do the number on a 125mm MAK, and
of course especially true when it comes to DSOs.

In situations like this, one must walk a tightrope, balancing the enthusiam of
a fledgling observer with the need provide realistic information so that others
will not be mislead.

My suggestion: If the fellow happens to live in my neck of the woods, I would
be more than happy to drive up to the mountains some moonless night so we can
compare my 10 inch F5 Asian Astromart special with his 125mm scope.

Over the years I have enjoyed several 125mm scopes for viewing DSOs, somehow
that size provides enough aperture to see some detail without being overwhelm.
I enjoy particularly in open clusters like the Wild Duck, nice faint little
pin-points.

But as we know its about aperture....

jon
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