[AZ-Observing] Re: The Orion 120mm ED Refractor
- From: DBogan3220@xxxxxxx
- To: az-observing@xxxxxxxxxxxxx
- Date: Sat, 5 Aug 2006 23:39:53 EDT
Then why bother with a refractor. Celestron had the C5 Schmidt Cass they
marketed for years and produced decent color free images. The Orion Achro
Doublet is OK but being an Achro suffers from Chromatic Aberration with the
corresponding loss in contrast due to CA and Sphero Chromatism. Again the fix
is
simple a Newtonian has all the advantages and the cost in the most minimal.
Both
the Orion Achro and APO are relatively long for their size. If what you are
looking for is a quick setup scope for the moon or planets then to me it would
be the Newtonian. The big plus for the short focal length APO is the
portability and the high contrast available when you want to take the
instrument to
high powers. Of course if your interested in wide field Astro-Photography
with 35mm or the 6X7 film format or CCD then the APO is the way to fly. Last I
might mention that a lot of people don't see the Chromatic aberration in the
doublets. Its come to mind that a lot of Americans out there are color blind.
So a short focus Achromat is going to appear quite good. I have perfect color
Vision and I find the color in the Achromat to really objectionable esp at
the higher powers. I've come to this conclusion because of all the reports
I've read about how people just don't see the color error in the Achromat at
all. Even when you explain it to them they still claim they just don't see it.
Clear Skies
Dwight L Bogan
In a message dated 8/5/2006 6:13:39 P.M. Pacific Standard Time,
stan_gorodenski@xxxxxxxxxxxxx writes:
remember Orion had a 5" refractor that they called an ED(I think)
5-10(?) years ago. It was in a white tube and was fairly inexpensive. I
looked through one at RTMC and it seemed good to me, but I am probably
not hard to satisfy in this regard due to my ignorance of really super
refractors. For some reason they stopped producing it.
Last year when I was in NM I stayed overnight at the Oliver Lee Memorial
state park south of Alamogordo. I got in late at night, and as luck
would have it a person, Fred Sweeney, needed to have his vehicle jumped
so he could charge the car battery in case he needed to take his wife to
the hospital. He had an Orion 5" refractor set up. It had a white tube
but was not the ED. Although not an ED I was impressed at the quality of
the images, if you do not demand too much. When necessary, he used a
lens from Orion that is supposed to reduce the chromatic abberation. If
one is not too demanding, the Orion is probably a real bargain for the
price.
Stan
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