WTB: Large Glass Prism

[buffo]

They're selling fairly large prisms on e-bay for like $30... They're close to the dimensions you asked for too. Here's a link:

http://cgi.ebay.com/Vintage-optical-...item439b693c6a

Adam

[Jem]

Nice find Adam, thanks.

I'll wait to hear from daedal first as it would seem unfair to buy these, after all he's making the effort to sort something out for me.

I searched Ebay (inc. Ebay USA) but my search didn't turn these up, not sure why.

Cheers

Jem

[MechEng3]

I have one here that is 4.2" on the faces and 3.4 accross. I would have to have a GOOD trade for it...it came out of a WWII bomb site from a B-17. An exec from Western Electric gave it to me a few years ago.

[danielbriggs]

I searched Ebay (inc. Ebay USA) but my search didn't turn these up, not sure why.

Things listed on ebay.com will NOT show up on ebay.co.uk. The two sites are completely separate. Even if you search items "from the USA/worldwide" on .co.uk. You have to explicitly go to ebay.com and search there. eBay made the change probably 12 months ago and it caused a huge outcry of sellers thinking they would loose out on a huge customer base and profits (they were probably right!). eBay's reply was simply "buyers will have to check both sites".
If you were in the US and listed something on .com, and wanted something to appear in the UK site, you would have to list the item again on .co.uk (and pay the fees again!).
At least that's my understanding - could have changed since...

[142laser]

Hi Jem,
Most long prisims like that are from WWII tanks and are not dispersive- those will not work. I would also like a prism like that but they are hard to get. If you use a collimated poing source you will get the best results. Look for say flint glass. Best, Phil

[-bart-]

Hi Jem,
Most long prisims like that are from WWII tanks and are not dispersive- those will not work.

An achromatic prism, great

[Jem]

Hi Jem,
Most long prisims like that are from WWII tanks and are not dispersive- those will not work. I would also like a prism like that but they are hard to get. If you use a collimated poing source you will get the best results. Look for say flint glass. Best, Phil

Thanks Phil

I appreciate the info and am pleased I found out before I bought one, i'm surprised they are not dispersive. I don't suppose you know of a source of a decent quality one that will do what I want do you?

You mention 'flint' glass, I suspect that's around 1.6 or 1.7 refractive index as opposed to 1.52 for BK7 glass. That should give much better dispersion right?

Anyway, if you have any suggestions i'd be most grateful as I know you can turn up some really cool gear

Cheers

Jem

[daedal]

Thanks Phil

I appreciate the info and am pleased I found out before I bought one, i'm surprised they are not dispersive. I don't suppose you know of a source of a decent quality one that will do what I want do you?

You mention 'flint' glass, I suspect that's around 1.6 or 1.7 refractive index as opposed to 1.52 for BK7 glass. That should give much better dispersion right?

Anyway, if you have any suggestions i'd be most grateful as I know you can turn up some really cool gear

Cheers

Jem

Hmm... interesting... I just put mine in front of some sunlight and I can see the full spectrum nicely spread out.

--DDL

[Jem]

Hi Mo

PM sent.

Jem

[daedal]

Jem, sorry this wasn't what you wanted... I recalled wrong. oops...

But... I figured since I took those pictures, and they do show some fancy colors, I'd just post them here for fun

Here's some Florida sunlight for you all

The yellow was much more pronounced in reality, and green was less 'faded'

And here's whatever sunlight can be seen in this corner...


And the culprit behind it all


Enjoy;
DDL