reflectivity paradox

Some reflector telescopes have one or more convex secondary mirrors, most notably the Cassegrain and Schmidt camera types, but all have a concave primary mirror. Concave mirrors cause the reflected light to converge to a common focal point, while convex mirrors cause the rays to diverge, or spread apart. Don't confuse diverging with diffusing, however. Both types of mirror create specular reflections - which is a fancy term meaning you can see images in the reflections. Diffuse reflectors, such as paper, do not produce images.

yup you know your shit beeble
yeah I would love to build one of those telescope with at least a 10 inch primary mirror.
what I noticed in my growroom is that before I put in mylar the white walls seemed to brighten up the whole room better than the mylar does.

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Originally Posted by harmonicminor

yeah I would love to build one of those telescope with at least a 10 inch primary mirror.

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Lemme know. I've got all the design formulae you'd need and a bunch of resources for telescope-making supplies and equipment. I can sure help you put together a nice large-aperture Dobsonian or something, probably for under $500.

cool bro email me at [email protected]

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Originally Posted by harmonicminor

I have rubeed on mylar with rough hands and made little scratches all over it to diffuse the light better and that seemed to work ok.
hey how about a convex mirror?

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Wow..you wrecked your Mylar dude. Study light refraction it will help you understand a little better what you are trying to do. Mirrors may reflect light the best. But for growing the problems mirrors have are heat spots and second and 3 order harmonics of the light spectrum to add to the adverse affect of the heat spots.

Mylar on the other hand gives the reflective properties a good partner. No hot spots and 98% lumens reflection.

but theres one thing
when the mylar isnt perfectly flat I seemed to notice hot spots whereas a mirror wont do that. I know you are probably right though. and I have plenty of mylar so I'm not worried about ruining it. what happened actually is I sprayed some takedown spray for pests and some got on my mylar and dulled it so while wiping it off I created scratches on it. It shined it right up though and brought back some effectiveness. Heres another Idea for you what about if you used two mirrors for a reflector up by your light? the reflection of the light bulb might be as bright as the bulb itself therefore increasing the effectiveness almost 3x. I have seen on a science website where they increased effectiveness of solar cells by 3x by having mirrors reflect light from the sides and into the solar cell. being the mirror is flat I would think it wouldnt create any hot spots hotter than the bulb itself whereas the standard reflectors are bent and compress the light therefore creating hot spots.

and one more thing
Im not even using mylar at the moment white walls on two sides and a tarp thats silver on the inside and brown outside making the other two walls. I am running a 1000w hps with a hortilux bulb and a 4 bulb teklight and two 2 bulb 2x overdriven t8 4' shoplights in a space about 8'x10'. the plants are more towards the center also and recieving plenty of light.

Well ok then...why do you try a grow with mirrors and see how it goes. Trial and ERROR is the best teacher. Just put a smoke alarm and fire extinguisher near your room I think you may need it....lol

I have another idea
build a box that works kinda like a huge periscope with 1 mirror and can shine just the reflected light down at the plants. it could take adventage of all the lumens at just one spot. maybe just use it for flourescent lights.
another idea would be a spinoff of the reflector idea make it so the light reflects down from the sides at a farther distance so you wouldnt need a light mover
possibly try with mylar reflectors as well and do side by side comparisons

the reflector in my teklight is more like a curved mirror than mylar

I could be totally wrong about this but who knows
without experimentation we will never find out

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