I wouldn't buy a short focal length achromat. If you truly want a short
focal length refractor for a reasonable price I would step up to ED glass
and buy the Orion 80mm ED giving up some light gathering for color
correction. Otherwise I would buy the Orion 120mm F8 refractor which has
been given very good reviews also. You might want to hold out for a bit
since the rumor is Synta (who makes the Orion refractors) is coming out with
100mm, 120mm and 150mm ED refractors to complement their 80mm ED refractor
(which Orion is selling like hotcakes ...)

"André P." wrote in message
...
I Alan,

I have the project to buy Orion 120mm ST F6, perhaps APM 102mm (China)
for observing at low power.

Thank.


Alan W. Craft wrote:
On Mon, 06 Oct 2003 10:00:08 -0400, "André P."
....reflected:


Hi all !

Since I have only Newton type télecope, I don't have experience about
refractors.


Do you have a refractor, and will its focusser accept 2"
eyepieces
or a 2" diagonal? If so, then you'd almost have to go with a mirroring
diagonal. If not, then it's probably a 1.25" focusser, in which case
you
could go with either, a mirror or a prism.


Here my question:

Witch is the best between prism diagonal and miror diagonal and why ?


I personally prefer prisms, while others prefer mirrored
diagonals, but
with my preference perhaps the result of inexperience rather than having
tested both.

Give us some more information before we go any further.

Alan