What is this weird Nikon lens? Anyone has information?

[Macro_Cosmos]

I came across this weird while browsing an online Chinese store...

Seller claims it weighs 1.5KG and only focuses at macro distances. The listing price is quite cheap.
Looks really weird, the lens coating is dark blue.
Anyone has any information on this thing? Is it worth buying just to have, or toy around with?
1.5KG Oddball by Daniel Han, on Flickr

1.5KG Oddball by Daniel Han, on Flickr

1.5KG Oddball by Daniel Han, on Flickr

1.5KG Oddball by Daniel Han, on Flickr

1.5KG Oddball by Daniel Han, on Flickr

1.5KG Oddball by Daniel Han, on Flickr
First element from right seems to be hazy.

The blue coating looks so attractive!

[Bjørn Rørslett]

Looks like some kind of relay lens setup?

[Macro_Cosmos]

Looks like some kind of relay lens setup?

Seems like it could be for relay purposes.
I see it has 2 mounting rings, maybe it's for aerial use or military use, but then such a thing probably shouldn't/wouldn't end up in China. The seller also has 2 copies.

Would cost more to get it to Australia than to actually buy it...

[beryllium10]

It may be an extender tube for mounting a camera (or some other kind of optical instrument) above the eyepiece(s) of a microscope.  The collar at the top of your first photo looks like the kind of dovetail fitting used to join microscope tubes together.  If so, the optical components would indeed be intended to transfer the image from a microscope objective lens to a photo-eyepiece.  I don't know the terminology well enough to google the specific item you're looking at, but here are a few images of what may be similar equipment:
Trinocular photomicrography set-up: https://www.microscopyu.com/assets/museum/microflexpfm.png
Another one:  http://www.lmscope.com/produkt22/microbilder/Canon_EOS_80D_Adapter_Fotoport.jpg
Random photo of an extender tube with dovetail fitting:  https://www.picclickimg.com/d/l400/pict/302133978386_/Olympus-Microscope-Camera-adapter-tube-mount.jpg
Web page describing how to mount a camera on a microscope system; includes another picture of a dovetail coupling:  http://www.alanwood.net/photography/olympus/c-mount-video-bh2-microscope.html
Hope this helps ...
John

[Macro_Cosmos]

It may be an extender tube for mounting a camera (or some other kind of optical instrument) above the eyepiece(s) of a microscope.  The collar at the top of your first photo looks like the kind of dovetail fitting used to join microscope tubes together.  If so, the optical components would indeed be intended to transfer the image from a microscope objective lens to a photo-eyepiece.  I don't know the terminology well enough to google the specific item you're looking at, but here are a few images of what may be similar equipment:
Trinocular photomicrography set-up: https://www.microscopyu.com/assets/museum/microflexpfm.png
Another one:  http://www.lmscope.com/produkt22/microbilder/Canon_EOS_80D_Adapter_Fotoport.jpg
Random photo of an extender tube with dovetail fitting:  https://www.picclickimg.com/d/l400/pict/302133978386_/Olympus-Microscope-Camera-adapter-tube-mount.jpg
Web page describing how to mount a camera on a microscope system; includes another picture of a dovetail coupling:  http://www.alanwood.net/photography/olympus/c-mount-video-bh2-microscope.html
Hope this helps ...
John

Interesting, thanks for the information. The lens shown does weigh 1.5KG which is heavy and it can put out a fairly sharp macro image, which is colour shifted to green. It seems to be a rather large item. I wonder if it's radioactive or not, if not I'll buy it and see what I can get out of it.

[Akira]

The dovetail-ish joint looks fairly large and sturdy, which suggests that something large and/or heavy would be mounted.

Also, the excessively blue coating interests me.  I suspect it would be intended to the use with a specific spectrum like e, g or h line?  Or is it designed to be used as part of an electronic microscope?

The element far right shows a sign of yellowing.  I wonder if it uses thoriated elements?

[richardHaw]

industrial lens. probably for manufacturing of small items 
they appear in japanese auctions frequently and that is the description

[Macro_Cosmos]

industrial lens. probably for manufacturing of small items 
they appear in japanese auctions frequently and that is the description

Japanese auctions?!?!! Got a website so I can have a look at? I love these weird and non-conventional lenses! Were the ones you see exactly the same as this one, or just very very similar? Thanks! 

[Macro_Cosmos]

The dovetail-ish joint looks fairly large and sturdy, which suggests that something large and/or heavy would be mounted.

Also, the excessively blue coating interests me.  I suspect it would be intended to the use with a specific spectrum like e, g or h line?  Or is it designed to be used as part of an electronic microscope?

The element far right shows a sign of yellowing.  I wonder if it uses thoriated elements?

Nice find on the yellowing element... I don't want to gamble it. If it's radioactive, getting my friend to bring it to me from China will be an extremely stupid idea as I could get her into serious trouble. I think I should just buy it and leave it a my grandparent's place.

[Macro_Cosmos]

Kind of looks like this lens, top left:

[Dr Klaus Schmitt]

Kind of looks like this lens, top left:

Well, this is a set of three Micro Nikkors used for micro circuit making (chip making),
so maybe it was a relay lens used for this...?

[Macro_Cosmos]

Well, this is a set of three Micro Nikkors used for micro circuit making (chip making),
so maybe it was a relay lens used for this...?

Yep. I tried looking up that weird thing on the top and found no information. As a lucky owner of a UMN lens, I am getting really interested in this topic.

[Dr Klaus Schmitt]

Yep. I tried looking up that weird thing on the top and found no information. As a lucky owner of a UMN lens, I am getting really interested in this topic.

What makes you think you own a UMN lens? Maybe it is just the condensor system to be used with them? Which was needed for this setup btw. ;-)

[richardHaw]

Nice find on the yellowing element... I don't want to gamble it. If it's radioactive, getting my friend to bring it to me from China will be an extremely stupid idea as I could get her into serious trouble. I think I should just buy it and leave it a my grandparent's place.

auctions.yahoo.co.jp 
this place is filled with rats so be careful!