Posted By Judson Mitchell
On axis focus of the SP was sharp and maintained until about 80% out where sharpness began to deteriorate. Not objectionably but obvious. I was able to refocus "down" to regain sharpness at about 90-95% out to the edge. This direction of refocussing may say someting to those more knowledgeable about EPs. I would be interested in their comments. I did not observe any chromatic aberrations or distortions at the edge of the FOV. It was difficult to make any comparisons to other EPs. I used a barlowed 11mm Tele Vue Plossl (220X); the StarSplitter was about 255X; and an 8mm Hyperion barlowed to about 320X. As power increased a corresponding decrease in sharpness and contrast was observed which should be expected. No real other comparisons or conclusions therefore could be made by me. On a 3-4th mag star slight bloating began at about 90% out and gradually increased to the edge.