I love star trail photos and thought I'd try taking a few while at the beach. I brought my camera and tripod and favorite star gazing app for the iPhone but, what I didn't count on was the humidity. The air is so thick that all I can really see is a handful of the brightest stars.
It takes the camera about 20 minutes to process a photo like this - 10 minutes of actual exposure time plus another 10 minutes reducing the noise - so I have a lot of time to look at what stars I can see and to compare them to the iPhone app trying to figure out what's what.
The first thing I learned is how to find the North Star - Polaris. Polaris sits almost motionless in the night sky and all other stars seem to rotate around it. If you point your camera at Polaris and take a long exposure photograph then Polaris will appear to be the bullseye in the middle of dozens of rings of stars.
To find Polaris first find the Big Dipper. Using the two stars at the bottom of the bowl as guide, trace a line to the next brightest star. This is Polaris and is at the end of the handle of the Little Dipper.
Polaris won't always be the Pole Star because the earth wobbles a bit on it's axis. 12,000 years ago Vega was the pole star.
Anyway, perhaps sometime this fall, when the humidity is low and the stars are bright, I can find Polaris and get a really descent shot of star trails.