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Orion 100mm f/6 OTA
| Brand | Orion |
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| Availability | available |
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Product Info
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Reviews
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Feb 29, 2008
An Achro With Apo Desires
Pros:Adjustable lens cell; Nice balance between speed and power; Solid construction.
Cons:No Crayford focuser.
Comments:I bought an Orion 100mm f/6 achromat used from Orion several years ago, and this little scope has served me well. No, it's not an apo, but it sure acts like one at times. This achromat sports a 3.9" multi-coated lens that's nestled in an adjustable aluminum cell....a feature you don't find commonly in a scope in this price range, but a welcomed feature. Focusing is handled by a 2" rack-and-pinion focuser that is typical Synta, but very serviceable and usable. I've replaced the stock focuser with a Crayford focuser from an Orion 100mm ED, it fits perfectly, and works very well. The tube has a 1/4"-20 mounting block.
Bottom Line: Would you recommend this item? Yes
The wide field views through this scope are absolutely stunning! Even at f/6, you really have to look hard to see any chromatic aberration. Only the brightest of objects will show any color, and even then you have to look pretty hard for it. This particular scope acts as though it's an ED doublet. Any color that does render its head is easily tamed with a minus violet filter (I use a 2" Baader Fringe Killer filter).
This scope will handle both local solar system and deep space objects with aplomb. I really enjoy using this scope and it has met my needs without breaking the bank! If you're looking for a 4" fast achromat with "Apo" aspirations, then you won't regret giving this scope a try.Feb 29, 2008Short, Fast, and Sweet!
Pros:Short lengeth; Fast f-ratio with minimal CA; Light weight; Inexpensive.
Cons:Minor Chromatic Aberration (CA); Some lateral motion in focuser especially with heavy 2" diagonal and eyepieces.
Comments:I purchased an Orion 100mm f/6 OTA last year while preparing for a trip to Australia. I needed a telescope that would be short enough to fit in a suitcase, and still light enough to be used on a moderately sturdy camera tripod. Price was also a major factor, as I didn't want to risk a super expensive scope going through baggage handling and customs. After looking at a lot of options and reading many reviews and forum comments, I decided to try this scope. I have always been impressed with the performance of the Orion 120mm f/8.3, and I felt that I had a good chance of getting something in this faster scope that I would be pleased with! I was quite well rewarded!
Bottom Line: Would you recommend this item? Yes
I ended up staying for three months in Australia and this telescope performed better than I had reasonably hoped for. I was worried a bit about chromatic aberration (CA), but I found that my scope had much less CA than anticipated. Yes, there was a little, especially on very bright objects, but it was not really troubling. I did take an Orion 1 1/4" minus violet filter with me but never felt that I had to use it. During this trip I only used a variety of 1 1/4" eyepieces (UO Orthos, Modified Achromats, etc.) and a 60 year old 2" 32mm Erfle adapted down to 1 1/4". These were used with a 1 1/4" mirror type diagonal on a variety of "Southern" objects and I was very pleased with the results.
After returning to the USA, I mounted this scope on a Konus EM-10 mount (CG-5 clone) with dual motor drives and it performs admirably. I also began using an Antares 2" enhanced diagonal. Here is where I ran into problems with the stock focuser. I had originally cleaned up the stock focuser (removed the old "Chinese" grease and relubricated with white lithium grease). With the 1 1/4" diagonal and light weight eyepieces there seemed to be only minor lateral motion in the focuser. However, when I hung the 2" diagonal and used several different 2" Erfle eyepieces, the lateral motion and play became quite apparent. The stock focuser is definitely a candidate for replacement! I also noticed that some of the longer FL 2" eyepieces will not come to focus. There is just not enough "in travel" in the stock focuser for this combination. Possibly a different diagonal would solve the problem or a replacement of the stock focuser.
As for optical performance, I can't ask for more. Using modified achromat eyepieces on a night of excellent seeing, I have observed as much detail in M42 as I have many times with an 8" SCT. I have also pushed this little scope to 200x with a 6mm Ortho and a 2x 'shorty' barlow. On Saturn, the performance was outstanding with the rings shadow clearly visible as well as detail in the planet's disc.
I am completely satisfied with the performance of this scope and would highly recommend it to anyone that doesn't want to pay the higher prices for an APO or ED scope. It is a good grab-and-go scope, good for traveling, and a fine general purpose scope.Sort by
