What a wonderful start to 2022! I got to spend the new year’s weekend working with my parents to get a full-scale demo of the LEDs installed up at VBAS.
My last post coincided with an email to the VBAS board of directors explaining what I wanted to do and tacitly requesting permission. The discussion on the email list went well and I ordered the remaining materials. Everything has arrived, but the box for the aluminum channel was damaged and about half of the channel was missing. Oh well. I sent it back and re-ordered.
Rather than wait for the replacement aluminum to arrive, I decided to go ahead and throw the LED strips up into the planetarium dome’s recess, and then go back and install the channel one 5-meter string at a time.
But first, let’s take a look at the cost estimate I proposed to the board:
Not to shabby. When I first imagined this project back in the early 2010’s it would have been at least twice this much.
As shown in the previous blog post, I settled on dividing the dome into three sections to satisfy the maximum rated power draw of the LEDs as well as the anticipated voltage drop along the strips. I should have included the 14/2-NM wire needed to attach the power supplies, but it got left out since I wasn’t sure what kind of wiring would be available above the planetarium drop ceiling.
Friday – 12/31
On a previous visit to gather some measurements up at the planetarium I let myself get spooked. While standing on a ladder by the dome recess I heard footsteps and a voice coming from inside the attic, on the other side of the dome. Most likely I was hearing a hiker outside in the state park, but thanks to the magic acoustics of the dome it sounded as though the noise was “inside” with me.
Since I’m a big kid and not afraid of no ghosts, I asked my mom to meet me up at the facility on Friday to help with removing the old lights and prep for the new ones. Up to now VBAS’s dome recess had been using two sets of incandescent Christmas tree lights wired to large rheostat dimmers on the control console. We began by pulling the drop ceiling tile where the string lights go through a hole in the dome.
Oh. So the drop ceiling is only a few inches underneath an attic floor, and then string lights go into the attic. Only way to unplug them is to go up there..
And here we are. I’m surprised by the amount of stuff. I expected this attic area to be much less assembled and much more cramped. There’s even a workbench that looks like it was installed back as they built the planetarium. Anyone want some 60 year old wire?
Visiting the attic feels like unlocking a hidden level in a video game. I’ve been coming to this planetarium since I was a young’n and had not been up here before. For a couple of minutes I poked around to appreciate the sense of history, and maybe also to take stock of the rodent damage to avoid.
The first thing to greet you on the climb into the attic is this.. thing. It appears to be a fiber optic light that’s been mounted into the exterior of the dome. It was turned on and plugged in, but I don’t believe the circuit was live. Looking from inside at the dome, there’s no obvious spot where this comes through. It must have been painted over at some point.
And here are the string light outlets, with the wires routed through a hole into the recess track. I unplugged them and pushed the plugs through the hole.
Once the old lights were out, I got impulsive and decided to start wiring in the new LEDs. Since there was already a convenient outlet by the hole in the attic, I plugged in the power supply and we got to work:
But then, just as the second strip of LEDs was done being installed, a power outage hit the top of the mountain, and it got very dark inside the planetarium.
Luckily I was wearing a headlamp to supplement the only working emergency light. For a while I ran around believing I had tripped a breaker with the LEDs. Eventually I checked the Huntsville Utilities outage map, and sure enough there was a blip right on top of us:
And that brought a close to this first workday. We packed up in the dark and departed.