Orion SkyQuest question

I plan to purchase an Orion SkyQuest but unsure what the difference is as
far as seeing what objects with the 4.5, 6 and 8 dobs.
What is the difference in viewing details on
the planets, deep sky objects?? Any info appreciated.

For planet details and for DSO's, the more aperture, the better. Of course,
more aperture does mean more bucks. The brightness of an 8" vs. a 6" is in the
ratio of 64:36, almost twice as bright (but not quite a magnitude). But the
resolving power should be a straight ratio (i.e., 4/3). For times when
atmospheric disturbances are bad: You can mask down the aperture of a
telescope, but you cannot mask it up. So if a 4.5" or 6" would work better
under some circumstance, you can use a 4.5" or 6" mask with an 8". You will
need to make your own decision as to the value of the scope: Is the added
benefits worth the additional cost? A 6" F/8 scope will be a very nice one,
but an 8" f/6 one will give the same magnifications with the same EPs, with
more brightness and better resolution. The F/6 might be a bit more prone to
collimation problems, but with practice, you can get the collimation done just
as well.
Clear, Dark, Steady Skies!
(And considerate neighbors!!!)

On Sat, 16 Oct 2004 00:28:44 GMT, "David"
wrote:

I plan to purchase an Orion SkyQuest but unsure what the difference is as
far as seeing what objects with the 4.5, 6 and 8 dobs.
What is the difference in viewing details on
the planets, deep sky objects?? Any info appreciated.

If you dont buy the 8 , you will wonder what you are missing with
smaller scopes. F.W.I.W I have the 10 inch and I know anything bigger
isnt going to be easily transportable so I'm happy for now.

There is an incremental improvement in brightness and resolution as
you increase size and its a matter of what you can afford and how much
bulk and weight you feel happy shifting.

Geoff

I plan to purchase an Orion SkyQuest but unsure what the difference is as
far as seeing what objects with the 4.5, 6 and 8 dobs.
What is the difference in viewing details on
the planets, deep sky objects?? Any info appreciated.

As others have said, go with the 8 incher. Even consider the 10 but remember
that its pretty big.

Also, consider the Hardin Optical scopes, some of the vendors are selling the 8
inchers for $299 with about $30 shipping.

jon

"David" wrote in message news:0XZbd.503$Ug4.256@trndny01...

I plan to purchase an Orion SkyQuest but unsure what the difference is as
far as seeing what objects with the 4.5, 6 and 8 dobs.
What is the difference in viewing details on
the planets, deep sky objects?? Any info appreciated.

They're all good scopes and all good value for money, especially
at the current sale price for the XT-6 and XT-8.

The XT-4.5 is a fine second scope for anyone, but I would recommend
it as a primary scope only for people with very small children who
can't reach the (rather low) eyepiece height of the XT-6 and XT-8,
or in cases where ultra-portability is required. This scope gives
great views of the Moon, of the brighter open star clusters, and
of a few extended objects, and it does an OK job on the planets,
but a little extra aperture improves things a lot. Most adults
find the eyepiece of this scope uncomfortably low, although
there are some fairly simple solutions to that problem.

For better or worse, the XT-6 and XT-8 are very nearly the same
size -- determined, no doubt, by the desire to get the eyepiece
up to a reasonable height for an adult without any auxiliary
support. The XT-8 is somewhat heavier, but most people who can
carry the XT-6 can also carry the XT-8. Given those facts, the
only real disadvantage of the XT-8 w.r.t. the XT-6 is cost.
The bottom line is that if you can afford the XT-8, you
certainly should buy it, because it delivers significantly
better views of each and every object in the sky, especially
deep-sky objects.

For planetary observing, the XT-6 is just over some imponderable
barrier where genuinely fine planetary detail starts to be visible,
like the divisions within Saturn's rings and festoons within
Jupiter's bands. Moreover, at least in my part of the world,
the XT-6 is big enough that the level of planetary detail visible
is limited by atmospheric conditions rather than the telescope
as often as not. So the benefits of the XT-8, while significant,
are arguably not overwhelming.

For deep sky, however, the XT-8 is really quite a lot better,
regardless of atmospheric conditions. It's hard to describe
exactly what the difference is, but for any given object at
any level of light pollution, you'll see (say) 50% more stars
in the bigger scope, and just a tad more definition within
nebulous objects.

- Tony Flanders