DIY-Projector Plans and theory collection !!

[ace3000_1]

Heya teletag, i had a scope for a while and had a look around for a good while in the skies of Australia, i had a tasco galaxsee 675. Not a bad scope, but nothing compared to a newtonian, ive always wanted to build one of these and may do in the future, but time is always the issue with me latley lol

You are dead right about how we can relate a scope's optics to a projectors light engine, its what you say, its a scope in reverse, and its prety much how i started out in learning about light engines in the beginning. Just smaller focals is what we work with and somtimes a few different reflectors.

Trev

[Teleteq]

Lol

Well I'm working on projector Mk2.
I have been sucsessful in projecting around 2m wide 16:9

But my light source is a 150watt OHP
I'm hoping to get a 250+ MH system up and running
but suppliers in the UK are hard to find for the LCD etc.

Funny you should mention about making a telescope.
Thats exactly what I'm doing right now.

I'm hoping to get a robotic scope up and running in around 2 years. Take a look at my site at http://www.teleteq.mine.nu for
my project details (Still under construction )

Sorry of the thread hijack

[ace3000_1]

Nice

I started to make a robotic tracking satelite dish as i got into downloading live images from space from various satelites before i left Aust, its not very common but its around on the net. Ive got satellite tracking programs and a skywatch program with tracking software for a elqualatoral robotic tracking system if your interested. You just need to make a plc card for the comp and get a hold of 2 ham radio antenna rotators for the motorised mount. use this with the software and you can track anything in space lol.

As for the thread jacking yeah we better call it quits, email might be the go, all the best in your projects anyway.

Trev

[mathias]

I agree that the parobolic reflectors are best for parallel light raws and that is nothing new, BUT there are alot light we can´t use with the parabolic reflector, there for is the elepticalreflector a better choise because we can collect more light with it and yes the rays may not be completly parallel but that is not a problem, the condensorlenses correct this.

And the above picture is eliptical, is´t not bend in anyway it´s the reflection that make it look like that, this is still true if you look at the picture i took of my reflector you can see that you get strange reflections, the blacklines you see are reflections from the metalbox take another look !

[mathias]

I have one right here, it also uses a lens to concentrate the beam.

How can you have a lens that concentrate the beam, when u say that the electpicalreflector do the same ? Strange searchlight ?

[Mr.Kh]

The image in the post quoted below is incorrect optics btw. If you look at the two pairs of rays furthest to the right, their incident angles of reflection do NOT match their reflected angles. THe incident angles look about 20+deg where their reflected angles are more like <5deg.

Originally posted by mathias
As Hezz write there are many shapes of elliptical reflectors. But I think you have missed the most important why to use a elliptical reflector. I hope my drawing clear this up. The biggest reason why they use elliptical reflectors in most searchlight, is that you can use more light from the front light cone, that will get lost in a parabolic reflector. The elliptical reflector is the most effective reflector you can use.

Err well this post jumped a page, so look one back to see the image I'm talking about. Here's a link to the post: http://www.diyaudio.com/forums/showt...347#post338347

[ace3000_1]

mathias, ive been working with steel for the most part of my life, i am also a certified engineer in metal, i also have very good eyes, and im telling you its a bend. Buy one of these and prove us that im wrong because i can garentee you that its a bend. That reflector is a cheap press formed steal reflector and ends at the bend, the rest is the light guide to not waste light, nor to contaminate surounding areas, and to stop light comming out of other areas. This is just press formed into a one peice unit.

Trev

[ace3000_1]

How can you have a lens that concentrate the beam, when u say that the electpicalreflector do the same ? Strange searchlight ?

LOL the eliptical reflector concentrates all light gatherd to a secondary focal point, normal torch lights use parabolic, u can even test this with your finger. Dont go on shape mathias as parabolic reflectors come in manny shapes and sizes depending on their beam spread and are normally not drawn as a half circle either like you have ilistrated in your drawings, they have a slight PART of an elipse, but once again this depends on the aplication and the desiered amount of light to be reflected, also not all parabolic reflecters are used to reflect perfectly parabolic rays, some alpications like a torch have the beam spread slightly out. Buy a magna light if you want to see what a lens does to a torch and ajust the beam angle.

Trev

[mathias]

normal torch lights use parabolic

No they don´t, a parabolic reflector is not so deep.

Dont go on shape mathias as parabolic reflectors come in manny shapes and sizes depending

A parabolic reflector can not have any other scape than parabolic, if it´s deeper than a parabolic, it´s a elipticalreflector. If they use a mix of parabolic and eliptical in a torchlight I don´t know, but it´s alot deeper than a true parabolic. And this deep shape is what I am talking about. This deep parabolic collect more light than a true parabolic-reflector.

It´s pointless to argue about the picture, I say it´s not bend, and you say it´s bend, let them how watch the picture self decide.

Anyway I have proved with my own picture from a torchlight that the reflector has a shape more like a ellipse.

[mathias]

The image in the post quoted below is incorrect optics btw. If you look at the two pairs of rays furthest to the right, their incident angles of reflection do NOT match their reflected angles. THe incident angles look about 20+deg where their reflected angles are more like <5deg.

If that is my drawing your talking about, I know it´s little wrong, it´s not easy to draw this kind of things, the light source should be more backward in the reflector