The key concept is to use a 2″ diagonal to achieve an ultra-wide field of view. This setup allows the system to reach infinity focus. Surprisingly, GSO’s SuperView 42mm eyepiece seems to be a perfect match for this short focal length. So this is 6x magnification.
Before inserting an eyepiece, I tested for mechanical vignetting by placing my finger in front of the objective hood. I could clearly see it, so there is no mechanical vignetting.
When I focus on the optical axis, I can see some minor aberration at the edge of the field of view, which I expected. It’s not too bad, but when I intentionally focus on the middle of the field, the stars look good across the entire field of view. It provided a very comfortable wide field of view.
My ultimate goal is to achieve infinity focus through BinoTechno’s erecting mirror diagonal, which has an optical path approximately 30 mm longer than that of a conventional 2″ diagonal. I’m confident that the 54Ach should work well, since it has a focal length 50mm longer than the 55FL. As always, a shorter focal length is more challenging.
Once I have all the necessary parts in hand, I’ll perform the final test including 54Ach. Stay tuned!