University Optics Orthoscopic 4mm

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Brand and Model:University Optics Orthoscopic 4mm
Price ($USD):$59.95
Type:Orthoscopic
Focal Length:4 mm
Barrel Size:1.25 in
Apparent FOV:45.0 degrees
Field Stop Dia.:0.0 mm
Eye Relief:3 mm
Elements:4
Weight (lbs):
Description:

Vote Highlights Vote
University Optics Orthoscopic 4mm
Great planetary ep with good light transmission,sharpness and contrast with no lateral . No problem with comfort taking in the whole field without my glasses on. Great product Mr. Seyfried.


Stan Taylor Vancouver B.C.

Overall Rating: 10
Optics:9 Value:10
Weight: 10 (Trustworthy Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=492647

University Optics Orthoscopic 4mm
I bought the UO 4mm ortho as part of a set of four, including 25mm, 12.5mm, and 7mm (each reviewed respectively). I use these eyepieces with a small, off-axis dob (4" F/10).

Clean, simple, and lightweight, I use the UO 4mm ortho on a DGM Optics OA-4 for my highest power. At F/10, the field of view is flat to the field stop and sharp. On a 1010mm focal length scope, I find the 4mm useful for providing maximum image scale for lunar, planetary, and double star work. While presenting a narrow field of view, what is there is sharp. To ease tracking on my small dob, I don't hesitate to start viewing an object off axis and let it drift through the entire field of view.

Everything about this eyepiece is on the edge and, I admit, I gulped somewhat when I put in the order. The 4mm has a tiny field of view, tiny eyelens, and even tinier eye relief. (I still found this eyepiece more comfortable than a 12mm Koeing!) It takes my small scope to the (still usable) limits and is a challenge to focus and track. A 5mm might have been more practical for this size scope, but I was pretty adamant about having one eyepiece in my starter set that would take my quality optics to the limits.

That said, I love this eyepiece. It's like Mighty Mouse --small but incredibly powerful! Last night, I was observing the Double Double (Epsilon Lyrae) at 146X (UO 7mm) and thought I'd throw in the 4mm for the heck of it, not really expecting much given the seeing. To my delight, the 4mm framed this double duo perfectly and I could easily make out the pairings with the increased image scale versus the 7mm.

Obviously, you are going to have to use this eyepiece without glasses. Without glasses, I can take in the entire field of view as long asf I scrunch down the soft eyecup I bought for it.

I give the optics a 9 only because I've heard that Zeiss and Pentax orthos are even better. Frankly, these no-nonsense, solid little eyepieces strike me as flawless. Value is obviously a 10 and overall 9, only because I think it would be nice if they had integral eyecups. (The Orion full eyepiece cups work well.)

Overall Rating: 9
Optics:9 Value:10
Weight: 8 (Veritable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=131092

University Optics Orthoscopic 4mm
Stick your eye up there and get it full. Clear to the edge no, absolutely no false color. If you wear glasses well then get the 8mm and put it in a nice barlow. If you don't wear glasses then stop whine'n astronomy is a science and these occulars are scientifically accurate, less glass = more light. I like!!

Overall Rating: 10
Optics:10 Value:10
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=175344

University Optics Orthoscopic 4mm
I like all the UO orthos very much; the 4mm seems to be about the limit of the design - eye relief very short and eye lens very small. Definitely takes a little practice to get the hang of using it. Having said that, this is my very finest planetary EP on an f/9 refractor, even somewhat outperforming a 4mm Radian on good nights. But it is hard to use. Forget about it if you need glasses. Next on my wish list is the new Nagler zoom, we'll see how it compares to that....

Also I can't believe how cheap it is, considering the optical performance.

Overall Rating: 9
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43235

University Optics Orthoscopic 4mm
I like this eyepiece very much. Eye relief can be tight but I have actually found that Plossols have tighter eye relief when trying to take in the whole field of view. Light through put on these Orthos is noticeably brighter than more complex eyepieces. As a result more detail is seen at the same magnification. These differences can be difficult to discern when looking at something as busy and bright as a planet (except the image is still noticeably brighter), but become obvious when splitting close doubles or attempting to discern detail in nebulous objects. It is when light becomes a "precious commodity" that these Orthos really shine;-).

When cost is considered, these eyepieces (the entire U.O. Ortho line) are clearly an anomaly in hobby where perfromance is often exaggerated and cost is often inflated.

Overall Rating: 10
Weight: 5 (Veritable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43229

University Optics Orthoscopic 4mm
Tiny lens, small eye relief and field of view. However, not important eyepiece
specs for me since I'm using this one for planetary observations. Detail is very
sharp, bright and has high contrast. Great price too.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43234

University Optics Orthoscopic 4mm
As far as optical quality is concerned, I'd give this eyepiece a 10. However, the short eye relief and relatively narrow field (by modern standards) results in a 7 rating overall. However, I purchased this eyepiece for high power planetary viewing with my 6-inch f/8 Astrophysics refractor. When seeing permits, this eyepiece gives crisp detailed views of such objects. Here, the field of the eyepiece and eye relief are of no concern since planets don't require a wide field, so you don't have to place your eye so close. This is a great value for an inexpensive sharp planetary eyepiece.

Overall Rating: 7
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43233

University Optics Orthoscopic 4mm
10" f/4.5. Fine images. Clear, contrasty, sharp. Tiny eyelens and short eyerelief make it a little difficult to use. But the sharp views compensate for the inconvience.

Overall Rating: 10
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43231

University Optics Orthoscopic 4mm
Used for planetary (small FOV). Eyelens is unbelievably tiny. Tight eye relief. Detail is sharp, but no better than other good short eyepieces or Barlowed Nagler.

Overall Rating: 7
Weight: 3 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43227

University Optics Orthoscopic 4mm
Yes, limited eye relief and FOV - but probably not as bad as you expect. Orthos are much better than Plossls in this regard in short focal lengths. Still, probably unuseable for eyeglass wearers. Some internal reflection but it's easy to "lose" by shifting viewing angle a little bit. As sharp and bright an image as you're going to get. Slightly superior image quality to Pentax XL and Radians, if you can live with the short eye relief. FOV not an issue for planetary. And for sixty bucks! Definitely an excellent value. I plan to order the rest of the UO orthos.

Overall Rating: 9
Weight: 2 (Unreliable Vote)
Date:
By:
Link to this vote: http://www.excelsis.com/1.0/displayvote.php?voteid=43232

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