Planetarium Star Projectors

[Galvonaut]

Iirc it uses special magic seriously look at AVI website. It is a special scanning system meant for domes. I believe part of it is a fisheye type lens along with a bunch of effect. Look at the skylase that is there current product. Av-imagineering.com

That looks pretty cool! Thank you. I reckon there is a little bit of magic there as on the utube videos there is very little increase in divergence in the beam between top and bottom of the dome.

[Jem]

Try a fisheye lens, I think I mentioned this to you at the LEM

[Galvonaut]

Try a fisheye lens, I think I mentioned this to you at the LEM

Yes, thanks Jem. I tried throwing my 14mm over the laser aperture but guess I need a different type of lens or to make sure that the focal point of the laser is at the lens axis?

[mixedgas]

Yes, thanks Jem. I tried throwing my 14mm over the laser aperture but guess I need a different type of lens or to make sure that the focal point of the laser is at the lens axis?

There usually has to be a few achromatic lenses upstream of the scanners to achieve decent results with a normal photographic lens. You still end up with a 2-3X expansion of the beam.

The AVI lens was designed by folks who make wide angle lenses for full dome flight simulators. The Minolta lens AVi uses is far different then your typical 137' wide angle, and is designed for maximum angle with minimum defocus, which is a bit different then the photographic lens, which is designed for low aberration on a focal plane.

In the US this technique with laser projection is covered by a still valid patent, so one must be careful.

You can get the well designed lens from Pangolin.

Steve

[SpitzSTP]

Yes, there is some additional details and photos in this thread, my apologies its not really organized in any sensible fashion.

[SpitzSTP]

Chillers often have a pressure release valve across the pump. The valve has a spring loaded adjustable setpoint. If the laser shuts off the water, the valve opens. You put a small accumulator tank on the output to damp the shockwave when the valve closes. Its simples, and it may already be there. Without this, the pump motor stalls.

75% odds its already in the system. If not, the valves are not expensive.

My water to water exchanger has a five gallon tank. Yes, its saves a considerable amount of water, and it makes the laser more stable. Less fluctuations in the resonantor if the water is Konstant temperature.


Steve

Mine does not seen to have this feature, although like you said, it can be added. I do have a question after I took the top off the Electro-Impulse unit. What is this gizmo pictured? It looks like a spring-loaded valve but the other end is attached to the water jacket through what appears to be a capillary tube. I don't think the previous installation was using it with the Chroma 5.

[SpitzSTP]

Lots of wiring work to do this weekend. Ron built a new control system for the star projector. Getting it wired to the projector is about half finished. A retro industrial look is what we were shooting for in these new control panels. I have two old rackmount control panels that came with the machine, too far gone to restore. They came out of the booth in NYC and I will put them in the back of the rack, behind the door, as non-functional display.

[krazer]

Looks like an old school temperature control valve, the 'wire' looking part goes to an air bulb which outputs a pressure proportional to the temperature of the water, which is then used to open the valve to let cold water into the heat exchanger (this forming a closed loop temperature regulation system)

Nice looking system overall!

[SpitzSTP]

Wiring continues. I took the advice of Sr. projector expert, Ron W. and installed terminal strips to make wiring go faster rather than rely upon AMP/Tyco military-style connectors that are prevalent on the rest of the machine. I love my Stripmaster tool its been getting alot of use on this project. It occurs to me that I have been hanging out alot lately with my favorite stripper.

[polishedball]

Thanks for the update looking good.