As part of my efforts to explore the utility of 1.25" eyepieces for afocal use with my NVD Micro, I approached Gary Russell with a request to make his 50mm 1.25" eyepiece with filter threads cut next to the eye lens. He was not anxious to attempt this as it hadn't been done before but I am very grateful to him for agreeing to take on the challenge. This exquisite lens is now in my possession and I have some early results to report. The threads at the eye lens allow me to hard couple it to my Micro directly using 1.25" spacers. Last night I was out with a scope that hasn't seen a lot of use by me. It is a Short Tube 80 that was marketed by Bresser and I acquired in a thrift shop while on vacation to the west coast. The optics and focuser are quite fine and I had the new eyepiece coupled to them through a TV diagonal. This new eyepiece has a very long eye relief and I used a total of ~35mm of spacing between it and the ENVIS lens of my Micro. After screwing on my 12nm Astronomik H-alpha filter to the 50mm I trained the setup on the Heart & Soul nebulae with the Double Cluster right next door. Now here is the amazing part. I could not detect any edge of field aberrations. Stars were pinpoints throughout the entire FOV. I was so surprised I would let stars drift into and out of the FOV to see if anything changed but they did not. This is a 3.70 FOV at f/2.65 and it was beautiful. Clouds rolled in before I could move on to other targets. I just had to make this post as these ST-80 scopes are cheap and ubiquitous and with this new eyepiece can provide an exceptionally fine view of deep sky objects.
Edited by chemisted, 10 February 2021 - 04:42 PM.