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Product review: The Orion Stratus Wide-Field eyepiece.

Posted by Robert Piekiel   06/09/2005 12:00AM

Product review: The Orion Stratus Wide-Field eyepiece.
In the late spring of 2005 an S&T advertisement by Orion caught my eyes for a line of wide-field eyepieces with a 68-degree AFOV and 20mm of eye relief. Shortly after that, they appeared in the Orion catalogue that I receive on a regular basis. These eyepieces were being offered in focal-lengths that were similar to the Tele-Vue Radians (In fact the Stratus eyepieces are similar in other specs to the Radians as well – physical size, AFOV, eye-relief, etc) but the Stratus eyepieces were priced at $119 each. Intrigued, I ordered some, and began testing them on both conventional SCTs as well as short-focus refractors.
My interest in astronomy is both professional and personal. I’ve been a hobbyist for 35+ years, but more recently I have been employed at a local nature center doing public programs and classes on a regular basis. Public programs are an excellent way of judging the “ease of use” factor of a product, as you get a wide variety of observers at them, both skilled and unskilled. In order for an item to be accepted by all, it has to be easy to use.

I have a wide assortment of eyepieces from various manufacturers, but I have found that even the more expensive ones do not always fit the bill. Using an eyepiece with a long eye-relief is desirable (I myself wear glasses), as it makes it easy for ANYONE to peer in and see what’s there. The problem with some long-eye-relief eyepieces is that you can actually have problems by getting too CLOSE to the exit lens, and the field becomes distorted, obstructed, or hard to identify. A case-in- point would be the Radian eyepiece. Sharp as it is, it comes with an “eye stop” that has to be positioned a set-distance from the exit lens, and in order to see into the eyepiece properly, you have to look directly at the point the stop positions your head (different for eyeglass wearers vs. non-glasses wearers). So many times, I have to coach viewers as to how to get positioned with an eyepiece in order to see the field, but NOT SO WITH THE STRATUS!
The enormous 1-1/4 inch exit lens is very forgiving as to where in the 20mm of relief that you place your eye. Whether you’re close or far, you can easily see the field without kidney bean or other effects, making it ideal for novice and experienced viewers alike. The 68-degree AFOV is easy to get all of without having to move your head around in order to see all of it, something I’ve never been able to achieve with more expensive eyepieces.
Image quality is superb from edge-to-edge with the typical f/10 light cone of a commercial SCT. Switching to an f/5 refractor, the same is true, and the images are comparable to what you would expect “high performance” types like Orthos, except the Stratus gives a much wider field of view at all powers.

The Orion ads describe the Stratus as an 8-element design with fully multicoated optics. I can’t discern any light-loss with the Stratus compared to a 4-element Plossl, but I suppose it is possible for very faint objects. The available focal lengths (3.5-21mm) make the Stratus usable at a medium-to-high power eyepiece, which is where the COMBINATION of wide field and good eye-relief really come in handy.

The eyepieces have rubber grips, a large, white number printed on the barrel telling the focal length (easy to see in the dark), and, thanks to a dual barrel design, fit either 1-1/4 or 2-inch focusers. The only caution here is that the section of 2-inch barrel is only about ½ an inch long, so be careful not to let them slip out of a 2-inch focuser. They have fold-down, removable rubber eye guards, and can be used with digital camera adapters (similar to conventional Plossls) if you get the proper size for the eyepiece and your camera.

To sum it up, I would recommend them highly, as a very well-performing eyepiece that offers comfortable, wide-field views and a very forgiving 20mm of eye relief, allowing just about anyone to see what the telescope is pointed at with minimal fuss. If it’s easy for the novice to use, it will be easy for the professional. All this at a price ($119 each) that’s about half the competition’s. Robert Piekiel, 6-9-2005