# What is this optical device? **URL:** \ **Category:** Factual Questions\ **Created:** [January 18, 2011, 10:52pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136 "2011-01-18T22:52:10Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![blood63](https://avatars.discourse-cdn.com/v4/letter/b/97f17d/32.png) [@blood63](https://boards.straightdope.com/u/blood63)\ **Post date:** [January 18, 2011, 10:52pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/1 "2011-01-18T22:52:10Z")
This thing has been floating around our school for 20 years. It is black plastic and is attached to the end of a metal support rod. It has four openings, two rectangular and two circular. It has a lens cap for one of the circular openings. Inside are two translucent glass plates. I think it is an attachment for a microscope but I have no idea how to use it. I have googled microscope attachments but have not found an image that matches this. Does anyone recognize it? [Here](http://www.flickr.com/photos/10380117@N07/?saved=1) are some pictures of it. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [January 18, 2011, 11:05pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/2 "2011-01-18T23:05:01Z")
I must confess I’ve seen nothing like it. Does it have any lenses, prisms, or beamsplitters inside? The translucent glass pieces look like viewing plates (“frosted” glass is often used as a screen tyhat can be lit from behind), but it’s not clear why there should be two of them. I have a translucent plate on a viewing system atop my old microscope, so it could indeed be an attachment that will “project” the microscope image onto a screen for many people to view, and to allow you to measure things and sketch them. But I can’t be certain without knowing more. ---
**Author:** ![MindsEye\_Watering](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mindseye_watering/32/3619_2.png) [@MindsEye\_Watering](https://boards.straightdope.com/u/MindsEye_Watering)\ **Post date:** [January 18, 2011, 11:22pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/3 "2011-01-18T23:22:06Z")
My WAG: a laser collimator? ---
**Author:** ![minor7flat5](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/minor7flat5/32/258_2.png) [@minor7flat5](https://boards.straightdope.com/u/minor7flat5)\ **Post date:** [January 19, 2011, 12:01am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/4 "2011-01-19T00:01:40Z")
Looks suspiciously like gadgets they used to make to transfer film to video. You show the movie on the small screen and record it on video through the lens. Or something like that. ---
**Author:** ![Fubaya](https://avatars.discourse-cdn.com/v4/letter/f/c2a13f/32.png) [@Fubaya](https://boards.straightdope.com/u/Fubaya)\ **Post date:** [January 19, 2011, 12:27am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/5 "2011-01-19T00:27:13Z")
My guess is a component of an [optical bench](http://sciencekit.com/student-optical-bench/p/IG0023827/). You shoot light or lasers through different prisms and lenses and see what happens. They can be rails like this or can take up a whole table and bounce the beam all over the place. This could be for shining a light through the round parts and looking in the square parts to see what the glass does to the beam. ---
**Author:** ![JFLuvly](https://avatars.discourse-cdn.com/v4/letter/j/ac91a4/32.png) [@JFLuvly](https://boards.straightdope.com/u/JFLuvly)\ **Post date:** [January 19, 2011, 1:09am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/6 "2011-01-19T01:09:12Z")
It looks like the arm of an overhead projector. Nevermind, no it doesn’t. ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [January 19, 2011, 1:15am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/7 "2011-01-19T01:15:51Z")
Camera Lucida ---
**Author:** ![qazwart](https://avatars.discourse-cdn.com/v4/letter/q/5fc32e/32.png) [@qazwart](https://boards.straightdope.com/u/qazwart)\ **Post date:** [January 19, 2011, 1:39am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/8 "2011-01-19T01:39:52Z")
I’ve seen things like this in survey equipment that uses laser lights. Don’t know why it’s floating around in the school. Maybe part of a laser kit? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [January 19, 2011, 1:04pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/9 "2011-01-19T13:04:49Z")
> [@](#): > > Camera Lucida No way is that a Camera Lucida – they don’t have anything with frosted glass, and they’re generally wide-open sets of prisms without a case. ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [January 19, 2011, 1:17pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/10 "2011-01-19T13:17:17Z")
The post may just mean it was mounted on a post system like this unit: > **[6X Macro Video Imaging System - Discontinued | Edmund Optics](https://www.edmundoptics.com/f/6x-macro-video-imaging-system/11452/)** > > Edmund Optics (EO) has been a leading producer of optics, imaging, and laser optics for 80 years. Discover the latest optical and imaging technology. Does it look like there are any threads on the circular openings? ---
**Author:** ![Mr.Miskatonic](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.miskatonic/32/310_2.png) [@Mr.Miskatonic](https://boards.straightdope.com/u/Mr.Miskatonic)\ **Post date:** [January 19, 2011, 1:20pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/11 "2011-01-19T13:20:43Z")
The box itself might be an old laser collimator tester: > **[ParaLine™ Collimation Tester - Discontinued | Edmund Optics](https://www.edmundoptics.com/f/paralinetrade-collimation-tester/11575/)** > > Edmund Optics (EO) has been a leading producer of optics, imaging, and laser optics for 80 years. Discover the latest optical and imaging technology. ---
**Author:** ![Cheesesteak](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cheesesteak/32/3694_2.png) [@Cheesesteak](https://boards.straightdope.com/u/Cheesesteak)\ **Post date:** [January 19, 2011, 3:48pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/12 "2011-01-19T15:48:25Z")
> [@minor7flat5](#): > > Looks suspiciously like gadgets they used to make to transfer film to video. You show the movie on the small screen and record it on video through the lens. Or something like that. I agree, [here’s](http://www.oaktreevintage.com/Film-To-Video_Transfer_Boxes.htm) an example. The transfer box has one place to put the projector and one viewing screen. Maybe your box is to somehow incorporate two projected images at once, and give you the ability to see the result while taping? You would use the one lens cover if you were only using one projector. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [January 19, 2011, 4:14pm UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/13 "2011-01-19T16:14:03Z")
> [@](#): > > The box itself might be an old laser collimator tester: No. I’ve worked with several such shearing interferometers (I’m using one now). Most don’t have any frosted glass plates, and have one at most. There would be either the shearing plate itself in the thing or a place to mount it. And I’ve never seen one with a lens cover. ---
**Author:** ![blood63](https://avatars.discourse-cdn.com/v4/letter/b/97f17d/32.png) [@blood63](https://boards.straightdope.com/u/blood63)\ **Post date:** [January 20, 2011, 12:01am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/14 "2011-01-20T00:01:34Z")
[Here](http://www.flickr.com/photos/10380117@N07/) is a dissected view. Upon further inspection, inside are two wax blocks surrounding on all four sides by clear glass. One image shows what it looks like when I shine a light through one of the openings. Does this help? ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [January 20, 2011, 12:27am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/15 "2011-01-20T00:27:36Z")
I would expect the wax is a safe way to keep the glass pieces from being damaged in storage and is just a spacer that won’t mess up the frosted glass. ---
**Author:** ![Kilmore](https://avatars.discourse-cdn.com/v4/letter/k/a6a055/32.png) [@Kilmore](https://boards.straightdope.com/u/Kilmore)\ **Post date:** [January 20, 2011, 12:34am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/16 "2011-01-20T00:34:28Z")
A blue light for K-Mart? ---
**Author:** ![blood63](https://avatars.discourse-cdn.com/v4/letter/b/97f17d/32.png) [@blood63](https://boards.straightdope.com/u/blood63)\ **Post date:** [January 20, 2011, 12:41am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/17 "2011-01-20T00:41:09Z")
> [@Harmonious\_Discord](#): > > I would expect the wax is a safe way to keep the glass pieces from being damaged in storage and is just a spacer that won’t mess up the frosted glass. Think I mentioned that there is no frosted glass. The wax makes it look frosted but its clear. ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [January 20, 2011, 12:49am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/18 "2011-01-20T00:49:17Z")
cc ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [January 20, 2011, 1:17am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/19 "2011-01-20T01:17:06Z")
i think it is used with a ray box. Project light in and send it through lens mirrors and prisms to change the light in different ways. I little piece of dry ice or smoke in there and you can see the light ray paths. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [January 20, 2011, 1:20am UTC](https://boards.straightdope.com/t/what-is-this-optical-device/568136/20 "2011-01-20T01:20:55Z")
Wax blocks? weirder and weirder. I confess that I haven’t seen anything quite like it. All I can think of is some sort of photometer, for measuring the amount of light falling onto one of the faces, with the light passing through the translucent material and the detector registering the signal. But I’ve never seen a photometer built like that before. And I sure as heck never heard of one that used wax. [Next page](https://boards.straightdope.com/t/what-is-this-optical-device/568136.md?page=2)