Advice on projection system light house 250

[Rossf]

Hello peeps-for my demo days I’ve been playing with the idea of direct projection instead of digital projectors or big TVs as not all places I want to set up have either. Below is a photo of the Leitz projection system for SM (and presumably most black enamel scopes)
Don’t want to try hunt down the device apart from projection eyepiece and tilting mirror (I have the mono phototube at last!) on top but will obviously need to match the lumens output of the Leitz 250 housing which has 250w halogen bulb-can’t find any manuals for this lighting house but if anyone knows what sort of lumens we’re talking about for LED equivalent.
Will need to rig some equivalent setup or maybe strong enough LED going through old black labolux with back light entry and field diaphragm-I think the immediacy of direct projection could be cool plus using a round screen (plywood painted with home theatre projection paint) would be novel.
Any ideas or feedback on this idea…?
Regards ross

[Alexander]

Be careful! The lamp housing 250 could be equipped with several different types of bulb-holders and bulbs.
200 W HBO high pressure mercury
150 W XBO high pressure xenon (frequently found in similar setups as pictured)
250 W halogen (yours?)

They all need different power supplies and are in the range of 9.000 to 10.000 lumen. To find a LED that powerful will not be easy.

btw: I have one of those projection eye-pieces sitting unused on my shelf.

[PeteM]

FWIW, you'll be putting a lot of heat into your specimens compared to today's digital imaging and projection.

[Alexander]

Heat filters and IR blocking filters are mandatory using that type of illumination.

[BramHuntingNematodes]

Yeah uh you could look into some 20watt single dies from cree won't be quite as bright but tell you what just put the screen closer and turn out the other lights in the room

Screen flatness and surface quality is very important if you don't want to shake your screen around really fast like the mantis or whatever. I have used Denril and back projected on it. Works ok you might try other polyester drafting film or some film as smooth as possible. Pro movie screens are ok but work better when you sit far away from them.

[Rossf]

Thanks fellas but I’m not sure I was clear enough- I had no intention of using any of the pictured setup except what sits on top of the mono photo tube and a equivalent bright LED going into back of black labolux -the bulb for original setup was a 250 watt halogen arc lamp but just wanted the LED equivalent to the original 250 housing Lamp output lumens-I intended to use in dim room.picture of halogen lamp below-

[Alexander]

Are you sure that's a halogen bulb?

The LED you are looking for does not exist. Even the most powerful single dye LED is much weaker than a 250 W halogen not to mention XBO lightning.

[Rossf]

Thanks Alexander -at least I can now put the idea to bed!
Regards ross

[wabutter]

with that spectral curve, that is not a halogen lamp. Typically halogen lamps use a filament. The Leitz projectiion scope usually had a XBO lamp depending on vintage. 150W most likely but early systems used a 450XBO. You can't miss it. It is very large as is the power supply. Also that combo often melts the mounting media if the lamp is focused for maximum intensity. Good Luck.

[BramHuntingNematodes]

Here is my most recent projection setup using a monocular scope, >5-watt LED. 10x achromat, ultraplane low projection eyepiece and right angle prism back projected through a denril patch. It produces a small image at this distance. Larger image can be obtained by moving the screen but dims the image I guess as a quadratic function of the distance. I think with some of the brightest LEDs driven to their limit you could achieve good brightness with an image maybe 8 times this size. This is when using low power objectives. High power dims considerably as well. Alternative contrast methods would make this considerably more difficult.

[BramHuntingNematodes]

The frame is 5 inches square. Ultraplane oculars are neat they make a really nice, erect image allowing this achromat from the 30s to have near plan correction.

[Rossf]

BramHuntingNematodes that looks pretty cool set up-I thought it could be a nice break from eye strain using eyepieces-your cute little B and L continues to impress with its optic quality for its vintage-the image is indeed impressive with its planarity..
Regards ross