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Orion 50mm Correct Image - Right Angle Finder |
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REVIEW ARCHIVES Refractors Barlow
Lenses LINKS FAVORITE LINKS NASA
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Review For most of the 4 or 5 years, that I
have been actively observing, I’ve used various types of unity finders
such as the Telrad, or Daisy type red dot finders on my telescopes and
binoculars. I found them easier to use than powered finders. However there
were times, when hunting deep sky objects, that I wished that I had
something with a little more “oomph”. My technique was to aim to where
I thought something was, and then hunt around with my widest field
eyepiece until I saw the object. Generally, if I were lucky, I’d
find it in a couple of minutes, sometimes, much longer if I wasn’t as
lucky. The biggest problem was on objects that were high overhead, finally
after much procrastination, I decided to augment the Telrad with a powered
right angle finder. There were 3 reasons why I decided
on the Orion unit. The first was they had recently listed this finder for
a good price. Secondly, because of a neck injury, I am unable to twist my
head into awkward positions without some discomfort; otherwise, I would
probably have opted for a straight through finder.
Lastly, the Messier Marathon date was rapidly approaching, and I
knew my star hopping skills needed help, if I hoped to get some kind of a
decent score. I ordered the finder with the
optional dovetail mount, as my scope didn’t have one. It installed
without too much trouble. The balance of the telescope was affected.
Whenever I used my lowest powered eyepiece, a fairly hefty Orion Lanthanum
22 mm. Superwide, I found the front end would slowly sink downward
whenever the scope was pointed below around 20 degrees above the horizon.
This was fixed with a 2-pound counterweight on the rear of the mirror box.
Alignment of the finder was next. I
had some concern about how easily it could be done, as there are only 2
adjustment screws. I needn’t have worried though, as I was able to align
the finder very quickly, and correctly. Finally, it was time to give it a
try and see how it worked. Despite some minor complaints, I am happy with
the unit. My biggest gripe is it isn’t as bright as my Orion 10x50
Ultraview binoculars. Also there is a large difference in optical quality,
which is reflected in the price. The binoculars are fully multi-coated and
have very good optics. The
finder in comparison has quite noticeable spherical and chroma aberrations
on bright objects on the outer third of the field. This is seen on objects
brighter than around mag. 2. I didn’t see any on dimmer stars. However,
I was aware of this before I purchased the finder. For the amount of money
that I paid, I am happy with the finderscope. How Does it Work in the Real World
I
was very pleased when I used these in the field. The first major use, was
Messier Marathon night, 2002. I found that finding most objects was much
easier when using a combination of a Telrad and powered finder. For
example, I have always had a hard time locating M36, M37 and M38, I have
always had to spend a few minutes hunting them down, This time, I was able
to all 3 objects in less than a minute, by getting the general area with
the Telrad, looking in the finder and zeroing right in, as all were easily
visible. I did manage to find 87 Messier objects that night, under so-so
skies. Comet Ikeya-Zheng was very easily visible in the finder, although I
couldn’t spot it naked eye. Open Clusters and Globular Clusters were a
snap. Some brighter galaxies are visible in Mag 5 skies.
All in all it’s a keeper. Pros: Good
value for the money. Works
nicely in conjunction with a Telrad or Rigel Unity Power Finder. Cons: Spherical
aberration on bright objects on outer third of field. Not recommend for use by itself, (I think it’s easier to use a straight- through). Submitted by Paul Hart - USA
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