Simple POD Light Shield
Since both of my Light Shields made from tarps hung on ropes from nearby trees came down in recent strong winds, I decided I needed to come up with an alternative solution to some neighbors' bright lights that shine beyond their property line (this type of light nuisance is known as "light trespass"). SkyShed POD is developing a "POD Shield" as an option for the POD. I'm sure their solution will be a nice addition to the POD for those wanting a more professional and semi-permanent solution. But I wanted a simple, easy on and off, solution. All it needed were some long rods and black cloth.
I had a small piece of black cloth leftover from a larger piece that I use to cover my head when at the eyepiece during the daytime, and I used that for a test. I purchased three 48" x 0.75" wood dowels from a hardware store (cost about $12). I cut them in half to have six 24" rods. The rods slip into holes that already exist at the top of the POD walls. I draped the cloth over two of them for the test. It was very effective in blocking the source of the bright lights from getting inside the observatory. Since the test worked, I purchased a long piece of black cloth from a local fabric store (cost $10). I cut it to 126” by 21", which allows full horizontal coverage of the open dome. I also added some plastic caps to the top of the rods (cost $4). Now, I can block the nuisance light(s) whenever the dome is open in their direction. Total cost $26.
Depending on the number of offending lights, I can have a narrow shield (seen in the photo at the top of the page), or a wide shield covering a wider area or even the full width of the open dome (seen in the photos below).
I simply unroll the needed amount of cloth, insert the end rods into two holes in the POD walls, and then insert one or more middle rods in other holes to force the cloth to follow the POD wall. I added clips on these support rods to hold the cloth in position. I made the height of the cloth sufficient to block the offending lights when I'm standing up inside the POD. That completely blocks light from reaching the telescope, but it does not impact my sky coverage too severely.
When the lights are turned off, I need to rotate the dome, or I’m ready to close the observatory, the Light Shield is removed and rolled up into this small package:
It can then be easily stored in a POD bay. A simple but effective solution to blocking nuisance lights in my otherwise very dark sky site. And no more wind damaged tarps to replace.
Friday, November 12, 2010