Is home built membrane reflector possible?

[dddaidl]

I was thinking of attempting to build a very large aperture membrane mirror (around 30") for amateur use. I have never built anything telescope related, so is this in any way possible?<br /><br />My method would be to stretch a sheet of high quality 5 mil mylar across a drum of some sort, where i can adjust the vacuum accordingly to get the correct focal length.<br /><br />I am certain that the shape will not be parabolic, but would it suffice? Has anybody ever attempted something like this? <br /><br />I just realized I can edit my post...<br /><br />I was thinking of building it based on the concepts discussed in patents 6332687 and 6113242<br /><br />If i can make an optical quality spherical mirror, i might try to build a design like herrig's tct, since it doesn't require parabolically shaped mirrors

 

[billslugg]

dddaidl<br />Welcome to SDC! Your first post is certainly an interesting one!<br />If you did as outlined, I think you could make an excellent reflector for a solar concentrator such as an oven. I do not believe that you could come near the accuracy needed to make a good image. You might get the curve accurate to within a mil or so. One mil is 25 microns. Green light has a wavelength of .5 micron. A good mirror has an accuracy of 1/4 wavelength. Your accuracy would be off by a factor of 200.<br /><br />Bill Slugg <div class="Discussion_UserSignature"> <p> </p><p> </p> </div>

 

[Testing]

Think about it bill, we now have adaptive optics. Why not adaptive elastisity optics. Think about it bill, there is a Magneto Rheolastic material that changes it's viscosity with application of a magnetic field. You cannot rule out adaptive elasticity can you?<br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> </div>

 

[vogon13]

Yeah, your idea makes a great solar furnace, but, IIRC, the shape of the mylar is closer to a catenary than a parabola.<br /><br />Not saying the right eyepiece couldn't fix it, but probably not worth bother.<br /><br />If you just wanted to use cheap eyepiece to aim it, and then use the mylar as a light bucket for a photometer to watch exoplanet transits, it might actually be a pretty good instrument.<br /><br />Just tailor your observations to the characteristics of the mirror.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[dddaidl]

What if I applied the concepts discussed in patents 6113242 and 6332687?(I would put the links to these but they are too long)<br /><br />They seem promising

 

[pyoko]

I use the lower layers of live squids stimulated by mild electrical currents to stretch the retina of endangered tigers that are tied together with carbon nanotubes to simulate aquatic eyes in a nitrogen/ vacuum environment. They last around 5 days in a plasma environment. Good luck with your project! <div class="Discussion_UserSignature"> <p> </p><p> </p><p><span style="color:#ff9900" class="Apple-style-span">-pyoko</span> <span style="color:#333333" class="Apple-style-span">the</span> <span style="color:#339966" class="Apple-style-span">duck </span></p><p><span style="color:#339966" class="Apple-style-span"><span style="color:#808080;font-style:italic" class="Apple-style-span">It is by will alone I set my mind in motion.</span></span></p> </div>