I have been going to the local star parties for several years and would like
to buy a 10 " dob as my first telescope. any suggestions what to buy and
what not to buy? Ron

Lots of thoughts on this one and lots of different ways to go.

Some have suggested getting a Meade 12.5 inch F4.8 scope, some have suggested
expensive scopes, these might well be good options for you.

Some things to consider. Size. A 12.5 inch F4.8 scope is quite a handful to
move around and fit into a car. The OTA is close to 60 inches long so it is
unlikely it will fit across the back seat of a normal sized car. Just getting
it out the door can be an issue. The general consensus on the Meade is that it
is a work in progress. Discovery mades a nice 12.5 inch F5 that is a finished
product. There is also the PDHQ 10 inch F6 DIscovery DOB. Size wise, it is
nearly as large as a 12.5 inch scope and about as heavy.

But as the owner of 8, 10 and 12.5 inch DOBs, I think there are many advantages
to the Asian 10 inch F5 DOBs, either the Orion XT-10 or the GS 10 which is sold
by a variety of stores including OPT, Hands on Optics, Harding Optical.

The OTA is only 48 inches long and weighs 35 lbs which makes moving the scope
as well as fitting into a car less of a task.

Optically these scopes seem to be quite good, some vendors are guarantying 10th
wave or better. The focusers are pretty good on these scopes and in general
they are a finished product that will not need significant tweaking just to get
the scope working. The "Correction Tension Springy Things" really do work and
eliminate the need to add balance weights and move them while observing.

These scope range from about $500 to $650 for the Orion XT-10. The new XT-10
has a couple of things that make it attractive, encoders for Digital Setting
Circles and a Pyrex mirror. For another $150 you can buy a handset with a
large database that turns this scope into a PUSH TO scope, a nice feature. The
Pryex mirror should help with cool down, though for me that is not a big
problem.

The one disadvantage to the XT-10 is that it is F4.75 rather than F5 as the
others are. This is getting into Coma Corrector territory, I am not quite sure
where this begins but at F6 it is not needed, at F5 it helps and at F4 it is
pretty much a necessity. Probably not a big difference between F4.75 and F5
but there is some to be sure.

The question of the 8 inch vs 10 inch vs 12.5 inch DOB has come up here over
the years on several occasions. I have had an 8 inch for several years and
added a 12.5 incher a few years ago. Several months ago a bargin OPT Star
Hunter 10 came up on Astromart, I jumped at the opportunity, partially just to
be able to answer this question at least for me.

What I have discovered is that most often it is the 10 incher that I use,
whether it is at home in my light polluted backyard, going to the mountains for
a nights observing or taking a long trip in our motor home.

Yes, the 12.5 incher does provide more glorious views, but the views in the 10
incher a likewise still quite amazing and joyful and it is just easier to deal
with.

So, you have been around, want to buy a 10 inch DOB, I think you have made a
good choice. There are many choices out there, what you choose depends on your
needs and situation.

I can recommend the OPT Starhunter 10 and the other GS DOBs, I think that when
Orion designed the original XT-10 they made some very wise design choices.
They realized that a 10 inch TUBE Dob is about the limit of practicality so
they optimized the size for both optical performance and
portability/useability. Optically they seem to perform well.

Certainly one can spend much larger amounts of money and get a nicer scope.
But these Asian scopes are quite nice and capable of providing many years of
serious viewing enjoyment.

Best wishes and dark skies

jon isaacs