For my spider assembly another hard decision. Do I buy or build. Should it be a 4 vain, curve, 3 vain, etc..

I decided to build. The reason (hmmm) to follow the theme of home made, an to save $ using materials I had or could acquire easily. So the question was what kind of spider assemble to build? I decided to go with a 3 vain. The spider vain material was my own idea. I found a lot of other ideas for spider veins off the Internet from wood, metal rulers, and wire. The materiel I used was PC card support backing. I had several old parallel/serial card holders laying around, an this seemed to fit the job.

After hammering them flat I soldered PC board stand off screws to the ends. This provided something to screw into. I then pop riveted the other ends to a 3/4" square stock piece of aluminum. My original design had one pop rivet per vain, which caused to much slop, so I ended up using 3 pop rivets per vain.

I used a shovel handle as the holder for the secondary mirror. The picture to the left shows the setup I used to glue the secondary to the holder. I used 3 blobs of silicon an drill bits as spacers. After the glue was dry I removed the spacers. I have also added a secondary heater while the assembly was under construction.

I used several resistors in series an in parallel to achieve about 1.5 - 2W of power with a 12V source. This should be enough heat to remove any dew.

After everything was assembled I painted everything flat black. I was fairly pleased with the end result.

To do it again I would change the way the adjusting screws worked.