Orion 50mm Correct Image - Right Angle Finder



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Date: 4-30-2002
Price: $76.95 + $8.95 for optional dovetail mounting bracket
Design: 50mm 90-degree erect/correct image finder, non-illuminated reticule. Field of View 5 degrees; Weight 18.6 oz
Description: Mid-sized finder scope that features a 90-degree prism diagonal.


For most of the 4 or 5 years, that I have been actively observing, Iíve 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 ďoomphĒ. 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, Iíd find it in a couple of minutes, sometimes, much longer if I wasnít 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 didnít 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 neednít 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 isnít 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 didnít 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 couldnít spot it naked eye. Open Clusters and Globular Clusters were a snap. Some brighter galaxies are visible in Mag 5 skies.  All in all itís a keeper.


Good value for the money.

Works nicely in conjunction with a Telrad or Rigel Unity Power Finder.


Spherical aberration on bright objects on outer third of field.

Not recommend for use by itself, (I think itís easier to use a straight- through).

Submitted by Paul Hart - USA

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