.965 eyepiece question

[Thefatkitty]

Hey all, hope you're good. Busy week here, started a part-time job today

The other weekend I tried to convert my Towa 3" from a .965 focuser to a 1.25" Not much luck, as the 1.25" was just a bit short:



Not to mention the stock .965 R&P is just so much better than the all-plastic one I was trying to replace it with, so back went the stock focuser, and I dug up some old .965 pieces:



The black-top lenses are the ones that came with this scope; the yellow and red tops plus the barlow are from my Sears 6441 60mm.

On further digging, I came across these:



I went out last Saturday, and though it was a lot of cloud dodging, I managed to get some great views of a crescent Venus and an almost equal crescent Moon. The 12.5 was OK, the 6mm's, we won't go there but the yellow-top 20mm and the 6X30mm were stunning, especially the 30mm!! I couldn't believe the sharpness on Venus with this lens, and the earthshine on the Moon was amazing! In the 30mm, you could probably fit 1 and a 3/4 Moon side by side to fill the FOV. This, from a .965 lens? The 20mm was almost as good, though not quite the black background the 30mm had.
I used both the 20 and the 30mm in the Sears 2X barlow. I expected a bad result... OMG, I could not believe it, again! The 30mm lens was just as sharp through the barlow, and the 20mm offered a better view and a slightly wider FOV than the 12.5mm I used on its own. Not sure why that is?
As for the Carton lens, I believe it has some promise, it just really needs a cleaning

You know, I can't get the image of the Moon last Saturday with that .965 30mm lens on an old 3" reflector out of my head. Maybe that's because I expect similar views such as that through my KK's or even ES's...

My questions are this: Why is it labeled as a "6X" 30" What does the 6 mean? And, does anyone know who might have made this? So unassuming, yet such quality...!!

Thanks for reading and possibly answering,

[notFritzArgelander]

JG would be the expert on whether my guess is right, but it is that the eyepiece is marked 6x because at 30mm fl it would give 6x in say an 180mm fl scope. Spotting scope eyepieces are often marked by magnification with respect to some supposed focal length.

[Thefatkitty]

Thanks nFA; I was hoping yourself, Gabrielle or JG would see this post. Honestly that was my first thought, a spotting scope lens. That may be all it is, but I still can't believe the views...!!
Certainly not a KK, but for something I found in a "sock drawer"...

[Lady Fraktor]

Here are the specifications on the Zeiss microscope eyepieces:
https://www.hitechinstruments.com/Produ ... piece-pair
Click on the specifications tab

I have quite a few 0.965" and really enjoy using them, the views can be quite spectacular.

[notFritzArgelander]

Thanks nFA; I was hoping yourself, Gabrielle or JG would see this post. Honestly that was my first thought, a spotting scope lens. That may be all it is, but I still can't believe the views...!!
Certainly not a KK, but for something I found in a "sock drawer"...

Here are the specifications on the Zeiss microscope eyepieces:
https://www.hitechinstruments.com/Produ ... piece-pair

I have quite a few 0.965" and really enjoy using them, the views can be quite spectacular.

Yes indeed. Just because it's 0.965" doesn't mean it's inferior in any way optically. Microscope eyepieces work fine!

[j.gardavsky]

Hello Mark,

I would keep the telescope for the RMS microscopy standard, as designed.
There is a mass of the 0.965" (RMS) microscope eyepieces on the eBay, and even some excellent ones in the price range up to $200, like the CZJ Abbe orthos to pick https://picclick.de/Foto-Camcorder/Tele ... ss+okulare

With some luck, you can also find the legendary Tak Abbe RMS orthos (TS in triangle), which don't break the bank https://www.intercon-spacetec.de/aktion ... 4-5mm.html

I have been using the CZJ A 12,5x (f=20mm) Kellner on the galaxies back in the day,
https://www.google.com/search?q=Carl+Ze ... -LzCflB11M
still keeping it, and as well the CZJ orthoscopic Kellner 12,5x.

Otherwise, there are lots of the microscopy eyepieces to avoid using them on the astronomy telescopes, so ask me first, and buy after.

To each telescope its own,
JG

[Piet Le Roux]

My first telescope is a 80's Carton with a 0.956 inch eyepiece(I got it from a pawn shop with no eyepieces) holder tube that could be extended for back focus, I removed the tube and modified the focus tube with a lathe to except a Baarder eyepiece holder which I secure with a grub screw.The problem is there is no going back to its original state but it now looks like it was originally made for 1.25", at the time i just wanted to get viewing!

[j.gardavsky]

JG would be the expert on whether my guess is right, but it is that the eyepiece is marked 6x because at 30mm fl it would give 6x in say an 180mm fl scope. Spotting scope eyepieces are often marked by magnification with respect to some supposed focal length.

Re: 6x on the microscope eyepiece

The magnification value on the eyepiece refers to the standard 250mm close observing distance of the eyes.
The equivalent physical focal length of the eyepiece is 250mm divided by the magnification value,
in this case: 250mm/6x = 42mm

Regarding the insert tube of the microscopy eyepieces, there are 3 standards:
1. RMS 0.965" - most of these eyepieces have AFOV around 40° or smaller
2. Insert tube standard for the projective (photo) eyepieces: between 0.965" and 30mm to prevent using the projective eyepieces for visual
3. Metric 30mm for the stereo microscopes and for the new binoviewers

There may also be some other insert tube diameters on the microscopes from the Far East.

Best,
JG

[notFritzArgelander]

JG would be the expert on whether my guess is right, but it is that the eyepiece is marked 6x because at 30mm fl it would give 6x in say an 180mm fl scope. Spotting scope eyepieces are often marked by magnification with respect to some supposed focal length.

Re: 6x on the microscope eyepiece

The magnification value on the eyepiece refers to the standard 250mm close observing distance of the eyes.
The equivalent physical focal length of the eyepiece is 250mm divided by the magnification value,
in this case: 250mm/6x = 42mm

Regarding the insert tube of the microscopy eyepieces, there are 3 standards:
1. RMS 0.965" - most of these eyepieces have AFOV around 40° or smaller
2. Insert tube standard for the projective (photo) eyepieces: between 0.965" and 30mm to prevent using the projective eyepieces for visual
3. Metric 30mm for the stereo microscopes and for the new binoviewers

There may also be some other insert tube diameters on the microscopes from the Far East.

Best,
JG

Thanks. You're the man.

[j.gardavsky]

Thanks. You're the man.

I have just two working microscopes (Leitz and ZEISS), and socks drawers filled with the micro eyepieces and accessories,
JG

[Thefatkitty]

Thanks for the replies everyone; would've responded sooner but was at my new part-time front-line job today...

JG, the info is appreciated. I was almost embarrassed to post this as I figure people just laugh at you for using .965's... But that 30mm, the two 20mm's and the barlow still amaze me. It's clear tonight so you probably can guess what I'll be doing and out with...

And I went digging through my old '61 Tasco 60mm box and took the barlow, another 20mm, and a 12.5mm. I also set the scope up as well; it's been almost 3 years, and it obviously takes .965's.

Gonna be a good night. Thanks again, all!!

[Lady Fraktor]

Very nice Mark
Antares has released their 0.965" Plossl eyepieces again, I have seen them listed at OPT and Highpoint though I am not sure if any Canadian dealers are stocking them at the moment.