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Two weeks ago I purchased an Orion delectric mirror diagonal from you and I am quite pleased with it (despite my prejudice for correct-image viewing). Compared to my prism diagonal, this one substantially improved many aspects of the image in my telescope -- generally brighter, more contrast, and a noticeable reduction in colour aberration (especially in the blue range). An additional benefit was focus stability (less wobble) with its slightly longer light path which decreased the extension of the focus tube by almost a full turn.
The most striking advantage with this diagonal was at higher magnifications. Viewing the Moon, I could use my zoom eyepiece down to 7mm and still retain reasonable contrast. And with the 9mm Nagler coupled with a 3x barlow I enjoyed my closest views of the moon to date; this works better at half-phase or less. Viewing Saturn was much improved, so that I could use my zoom eyepiece with a 3x barlow (though below 11mm the resolution does drop significantly, but that has nothing to do with the diagonal). Still with my telescope (90mm SkyScout refractor) I only saw one solid ring and the distinctive orb of the planet (the view would be better in early Spring).
I was most impressed with the diagonal while viewing Jupiter and its moons. Jupiter is about 100 million km further away than it was last year at this time and that makes the moons harder to see in the city. The Orion diagonal significantly improved my views of the moons (as far as seeing them as little jewels of light goes), especially last night (July 25) when Io and Europa were very very close together. With the Orion diagonal I could easily distinguish the two moons and even the dim Callisto was easy to see (Ganymede was there too). For comparison, I also viewed them with my old prism diagonal. Through the old one Io and Europa were quite difficult to distinguish and Callisto all but disappeared. At a rough guess I would say that the Orion diagonal increased the apparent brightness of the image by about a full magnitude.
I was also pleased to see the Southern band of Jupiter coming back, though it is not yet distinct.
With the Orion diagonal I was able to push my telescope down to the 3mm level (220 times). Past that and the contrast goes to nil, the image goes dark and the resolution becomes quite "watery". Generally I would say that having very good eyepieces made the difference. Having a better diagonal allowed these eyepieces to see more light and see more clearly.
I'm quite happy; I've achieved another "rung" on my cosmic distance "ladder".
cheers,
Robert Tzopa
Rating:  [5 of 5 Stars!] |
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