Wow, what a great collection! I would think the 28mm RKE would be a very cool view of the Saturn, Jupiter conjunction in December!
My gal and I recently (near opposition) observed Mars using the 28mm RKE with the 5X Powermate plus a 1.5-inch extension tube between the Powermate and the eyepiece. The 1.5-inch extension increases the 5X Powermate magnification to 6.2X.
The effective focal length of the combination above was 4.6mm, which in conjunction with my 600mm FL TV85 provided a 130X view, which was about optimal given our seeing conditions.
We were looking straight-through, no diagonal, via 3.5-inches of 2" extension tube inserted between the focuser and Powermate.
Although the exit-pupil behavior made eye-positioning a bit challenging to initially acquire, once positioned, the view of Mars through the 28mm RKE was really nice, with excellent contrast and sharpness and without vignetting.
The "floating in space" view added a nice aesthetic too --it was fun! My partner Esther particulary liked the Powermate-amplified view of Mars with the 28mm RKE.
We both kept thinking, however, that the experience would have been much more relaxing with the benefit of a polar mounting with RA drive. Trying to keep good eye positioning while readjusting the alt/az mounting for drift was a bit of a hassle.
Also: we tried out a 'Baader 570nm Orange Longpass Filter' with the above setup. The view with the 570nm filter was captivating, as the planet took on a very rich tangerine glow. The dark albedo features jumped-out strongly, surprizingly. The South polar cap also became very clearly defined, portrayed in a bright light-yellow caste. So, not very true-to-nature, but a very revealing and engaging view nonetheless. We now call the 570nm lowpass filter our "orange sunshine psychedelic fun filter"
A problem we did encounter with the 570nm filter was that it darkens the sky background glow severely, and so one has difficulty seeing the field-stop boundary. It thereby becomes challenging to acquire the proper eye positioning for the RKE 28mm when searching for the target. Again, RA clock drive would make this combo much more relaxing and enjoyable.
I see the purchase of a used GM-8 polar mounting in my future...
Edited by Thomas_M44, 07 November 2020 - 10:52 PM.