Posts Made By: Peter Albrecht

Hi, all.

Can anybody help me identify the eyepiece whose image is attached? (If that doesn't work, I've also uploaded it to http://members.aol.com/plalbrecht/eyepiece3.jpg). The only markings on it read "1 1/8" fl" No manufacturer or country of origin. Inside are two cemented nonidentical doublets separated by about a 1/4" wide fiber spacer ring. The two barrel components are both black anodized aluminum. The upper section has a straight knurled area. There is no filter thread. This must date to the late 1960s to mid 1970s because I've had it since then. It may be Edmund, I used to buy a lot of stuff from them back then (or from their Chicago affiliage, American Science Center) but I don't have any recollection of actually buying this from them. I'm also posting this to the classifieds section, I don't know if that's kosher but maybe more people read that.

Thanks in advance,

Pete

As part of another thread, the topic of radioactive war surplus optics, in particular eyepieces, came up. When I first heard this, I thought yeah, right, another urban legend. But I happened to have a huge old Erfle that apparently came off an M4 Sherman tank, and had just spent a lot of time making a wunnerful adapter to put it in 2" eyepiece tubes, when I heard that. So I had it checked out by a local hospital radiology department (after trying two fire stations and learning that one didn't have a clue and the other had thrown away its Geiger counters -- so much for the "security theater" of emergency preparedness, foreign nasties with dirty b--bs, etc). Sure enough, it was "hot" enough that one wouldn't want to put an eyeball behind it for any length of time. Like, when spending hours staring at deep sky objects. Now, just because it puts out alpha particles doesn't mean it's completly off limits. Alpha is easy enough to stop; a simple glass cover window would do it. But in this case, I gave up when I realized that the glass itself had turned brown from radiation damage, and my original idea of recementing the elements wouldn't fix that. A pity, because it's a wonderful hunk of glass and brass. For reference, I've again attached my image of this huge thing, with and without the aluminum adapter I made.

Here's a copy of part of a reply posted to a different thread here (under "help identify mystery eyepiece"). I figured this is a different topic and probably important enough to warrant its own thread.

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In the process of researching this, I found some links on the web that might interest you. Radioactive glass isn't limited to old military stuff. All this is from those happy days of yesteryear when we were watching newsreels titled "Our Friend the Atom" etc. :-)

http://www.orau.org/ptp/collection/consumer%20products/cameralens.htm

http://www.angelfire.com/electronic/cwillis/rad/thglass.html

http://medfmt.8k.com/mf/radioactive.html

http://hps.org/publicinformation/ate/q1356.html

http://www.universetoday.com/forum/index.php?act=ST&f=14&t=4986&hl=&

http://www.mod.uk/linked_files/dsef/hp/jsp392/pdf/chap47.pdf

In particular, that last one says

Thoriated Lenses
4723. There are currently two types of thoriated lens in use. These are the thorium fluoride
coated germanium lens and the homogeneous thorium oxide lens. The coated lens can present an
internal hazard if the coating is damaged leading to the possibility of ingestion of thorium. The hazard from the homogeneous lens is principally an external radiation dose to the eye.
4724. Equipments containing thorium lenses are also to be marked with a radiation warning
sign unless this is not possible for operational or other safety reasons.
4725. In applications where thoriated lenses are placed close to the eye, they are to be replaced with a non-thoriated substitute where operationally acceptable or where modification of the equipment is undertaken, a plain glass shield is to be introduced between the lens and the eye.

Hi, all.

Going through some old S&Ts, I found a review in the May, 1991 issue (p. 495) of a design called "Super Dome" made by Allan Guthmiller, Ace Domes Inc., Las Vegas.

I can't find any mention of this on the web. Since it's almost 14 years ago, has this design gone off the market? Too bad, as it looks pretty much like what I would need and the price of $300 (back then) was attractive. Guthmiller's name still appears more recently, in connection with RTMC and other astronomical happenings, but no mention of backyard observatories.

Thanks in advance,

Pete

I have a 32mm Erfle eyepiece that appears to be identical to the one shown at
http://astrosurf.com/re/eyepiece_erfle_32mm_surplus_20020726.jpg

I haven't seen another one like it, anywhere online.
Anybody have any idea what it came from? I think it's military surplus, because it has a focusing provision for a crosshair reticle. It must be fairly recent (WW2 or newer) because it has coated optics. The thread on the helical focusing collar is non-metric, 32 threads per inch, which makes me think it's U.S. military surplus.

I've had mine for about 30 years but never got around to making the necessary adapters to attach it to a telescope. I have done so now, and I have to say I think it's one of my better eyepieces. Out of curiosity, I'd like to know what it came from.

Here are some photos of my example:

http://www.petealbrecht.com/eyepiece/eyepiece1.jpg
(Rubber eyeguard is from some other application, from Surplus Shed; I don't have one like the one shown at Astrosurf)

http://www.petealbrecht.com/eyepiece/eyepiece2.jpg
(With two threaded adapters I made to attach it to an old Zeiss Jena prism diagonal, M44 x 1 threads, probably prewar since it says only "Germany")

http://www.petealbrecht.com/eyepiece/eyepiece3.jpg
(Eyepiece, adapters, prism)

http://www.petealbrecht.com/eyepiece/eyepiece4.jpg
(With adapters screwed together to make straight-through 2" adapter).


Thanks in advance,

Pete