LZOS / Rubinar 10/1000 Camera lens as scope

[Dodge]

Just for giggles, I've converted an old Soviet Rubinar camera lens to a telescope. The lens is a catadioptric design made by LZOS (maker of Tal glass, amongst other things) with a 1000mm focal length. LZOS also say these are suitable for astronomy, and actually add a visual back and EP's for that very purpose.

I decided to see if i could make a cheap grab and go scope of sorts as it fits on a camera tripod so added an M42/1 to t-thread adapter and EP holder to it. Just looking forward to a clear night to test it now!

[DirkSteele]

Nice idea. I am intrigued to hear how it performs.

[AndyH]

Niccce !

Markus Ludes of APM once had a section of their website that explained how to convert the two types of 1000mm FL lenses. There is a method to be able to let you obtain more infocus, that'll let you use a diagonal. I'll have a hunt and try to find it. Worst case, I have a print out that I can scan regarding it.

[Dodge]

Niccce !

Markus Ludes of APM once had a section of their website that explained how to convert the two types of 1000mm FL lenses. There is a method to be able to let you obtain more infocus, that'll let you use a diagonal. I'll have a hunt and try to find it. Worst case, I have a print out that I can scan regarding it.

I've seen this: http://web.archive.org/web/20011124004008/http://www.apm-telescopes.de/products/techspec/bw_improve.htm which I think is what you mean, but thanks for the offer of scanning. It's basically removing the infinity stop ring - it looks like a simple enough modification.

LZOS also do a 'Turist'-type attachment with an M42 thread for use with these (and other) camera lenses.

[AndyH]

Yeah, that's the one !

I've got the latter M42 attachment for lenses. I nearly died when I saw what price it's for sale at , these days ! Hopefully the site I looked at was simply extracting salty ammonia based liquids.

The item works well though.

Andy.

[Dodge]

Yeah, there's one for sale in Russia on Ebay for ~£63. Too much for me, if I found one for ~£20 I'd have it. There's also one on Ebay Canada with the Rubinar 1000 for £375!

[michael.h.f.wilkinson]

Nice one. That will make a neat little grab'n'go

[Dodge]

Hopefully I'll get a chance to test it tonight, the visibility is outstanding, albeit it quite windy.

[Dodge]

Finally got a first light of sorts, visibility wasn't great but managed to get it outside for a play at least.

Pros:

• Optical quality is excellant right across the FOV, it's bright and sharp. I read somewhere that it has a clear aperture of 100mm, and it's got a similar image quality to my Tal (both being 100mm F10 scopes), without any hint of the CA the Tal can get on bright objects.
  
• It's SO portable. Even with a big EP it's around 10" long, and it's not massively heavy.
  

Cons:

• The tripod mount is on a sleave containing bearings, allowing the tube to rotate with 4 'preset' click stops. This is great for framing, however focusing is also done by rotating the focusing collar and it has similar resistance to the tripod sleave making focusing a two handed job. One handed focusing just spins the lens in the sleave!
  
• Focusing is a bit of a task. A better solution would have been a visual back with a helical focuser, course focus could have been achieved with the lens and fine focus with the EP holder.
  
• With the long focal length, a finderscope of sorts would have been helpful. It's managable though, especially with my UWAN's.
  

To summarise I think it's a good quality camera lens and ok as a grab and go scope, it's not really any less hassle to set up than my Tal/AZ4 combination but it's much more portable. Image quality has a slight edge on the Tal, but not by much. With a helical EP holder it would be very good and with a diagonal, it would be excellent.

It's been fun, but I don't really know what i'll do with it - the opportunities for using a 1000mm camera lens are fairly rare, and I think for an impromptu session, the Tal will always get the nod.

[alan potts]

There was me thinking Lzos only made very high quality optics for people with deep pockets. They say you lean something every day.

Alan.