This make most of the views around the celestial north pole inaccessible.
The solution is to take out the light when I want to observe north.
While some of my friends suggested a B-B gun, or an arm mounted sling shot and a steel ball bearing, I wanted a process less permanent. After working through a dozen alternative ideas, I settled on shooting the light out with a laser.
In the close up picture to the left, you can see the small round circle on the base of the light. This is the photosensor. It is probably just a large area photoresistor.
When the light level drops below some pre-set threshold, the resistance goes up and this triggers a circuit that turns on the streetlight.
What if I could fool the streetlight into thinking it was daytime?
I tried shining the brightest flashlight I had on the sensor, but there was no impact. I tried shining a red laser on the sensor spot, but there was no impact. The light stayed on.
I was thinking of trying to place a mirror near the light to shine its own light on the sensor, but I realized this would just cause the light to go into some sort of oscillation.
As a last resort, I tried a 5 mWatt green laser pointer. No impact. I was pretty confident some power level would work, it was just a matter of finding the lowest power (safest) that would still reliably turn off the light. I had a 200 mWatt laser available but didn’t want to bring out the “big guns” unless I had to.
And if this didn’t work, I knew where to get a 2000 mWatt laser if I really needed it.
The laser stayed on all through the evening and the light stayed off.
I’ve used this device a number of times to turn off the street light and shoot northern shots.
Now I have a stable technique to turn off the streetlight whenever I need to.
I get a few funny looks from my neighbors, but I’m used to that.