I use to work for EPOI which back in 1970's owned Nikon and many other companies like Bronica, Fuji...etc.
I asked their Head Salesman if I could purchase some Demo Nikon Microscope eyepieces. He was nice enough and went to the lower level
of the building and searched for a series of Nikon Microscope eyepieces. He found a Nikon 5x, Nikon 10mm WF, Nikon HKW 10mm with
cross-hair reticle, Nikon HKW 15mm and a Nikon K20x. I also got a FM (Early model to EFM) and more all for $50!
I at that time had a Lafayette Galactic 70mm refractor. That scope had a 0.965mm eyepiece holder. Typical for Microscope eyepieces, their
OD is 0.913", so they are less in diameter than that 0.965" standard ,
In the 1980's, I had access to a professional Metal Lathe. I was able to produce three, 0.020" aluminum sleeves that I turned down from a 1.0" Aluminum round stock.
I made these, so I could put these sleeves over the Nikon Microscope eyepieces to use with my Lafayette Galactic's 0.965" eyepiece holder.
I sold off the Lafayette Galactic and then every scope from that point had either a 1.25" or 2.0" eyepiece holders.
I basically, mothballed those Nikon Microscope eyepieces.
Currently, I own a Questar Duplex and a 10" Meade LX850 OTA. I recently remembered that I had the Nikon Microscope Eyepieces
and I saw on eBay a Seller(China based) that offered a 0.965" to 1.25" eyepiece adapter for $7.95. It also include a 1.25" to 0.965"
I have accumulated quite a few Televue eyepieces. I own a 4mm & 10mm Televue Radians and a Televue Type 2, 16mm Nagler.
The Questar came with 2 Brandon's 16mm & 32mm. Those were Erfle designs.
Up to that point, my 16mm Nagler was my prized possession and there are Many reviews about this particular eyepieces performance.
Then that Chinese 0.965" to 1.25" eyepiece adapter arrived and I could finally use my Nikon eyepieces.
The Questar Duplex's views are incredible to start with. When I dropped in the Nikon's into the eyepiece holder, my mind
was absolutely blown away. These eyepieces were brighter, had more contrast and Detail than ANY eyepiece I own!!
The Nikon K20x was very close in magnification to my Televue Type 2, 16mm Nagler. This little K20x blew the doors off the
Nagler! In fact, I noticed by comparison of view of Jupiter as my test bed, that the Nagler had a warm and unnatural tone.
The Nikon K20x had just as good eye relief and offered more detail and contrast. The Nagler 16mm is 4x's the Nikon's K20x size!
I also added a Mitutoyo 30x eyepiece as well. This one has a strange 1.200" OD, so it's shy 0.050" from fitting a 1.25" eyepiece holder.
All of these eyepieces give you great eye relief and the best imaging I've yet to have seen.
Now I'm not going to get into a debate with Televue Owners but I will ask them to perform a simple comparison by duplicating what
I just found out.
These Nikon eyepieces are going for Dirt cheap on eBay. You could buy the same set and pay probably less than $160 for them all.
I could have saved myself a lot of money, if I had done this sooner!! Of course you will need that 0.965' to 1.25" adapter.
A CN friend of mine also owns a Questar Duplex. I told him about this and he purchased a use Nikon HKW 10 from eBay.
He used some flexible Stainless Steel tape to increase the Nikon's 0.913" OD up to the 0.965" OD.
He also confirmed what I said about the clarity and detail this eyepiece delivered.
These eyepieces will completely change your mind on what a Telescope Eyepiece will deliver as far as imaging.
So, if you are looking for a cheap but totally affordable way to improve your viewing, do what I did.
So far, 2 friends of mine, purchased these eyepieces and did the same test as I did. They were totally blown away too.