Night Photography Assignment 1: Stars

So I was hoping to get an assignment for this week in our class but I'm not sure if we will ever get any. I went ahead and made myself my own assignment: stars. I have tried to photograph stars in the past with not much luck. I have always liked "star trails" photography and hoped to make my own photos. Many people use computer software to layer a number of 30 second exposures to create a full sky of trails. I tried it in a single exposure. The only problem I got was it allowed in too much ambient light giving it a washed out feel.
I also read about "urban" star shots. One blog, Long Exposure Tips, discussed using a 50mm prime lens and opening up the aperture to f/2.8, lower the white balance to 2500K and shoot at a low ISO. This seemed bizarre to me as you typically need a high aperture with a long exposure so it doesn't create too bright a photo. I tried this a few times and found that the stars end up blurry and if the exposure goes to long, you get small streaks instead of stars.
I noticed on my long exposures of the sky, especially the third shot below, I am getting small red dots across the photo. Are these airplanes or a problem with my camera/lens? They seem to be in the same place on every photo. I was pleased how the sky in the long exposures of the second and third photos still stayed a dark blue instead of brightening up like the first photo. I adjusted the white balance on these photos to a lower level (Tungsten light, Approx. 3200K). I'm not too sure how to use these settings or even how to create my own. Maybe we will learn some of this in future classes. Here are a few of the better photos from this week:

6,404 second exposure, f/18, 50mm, ISO 100
45 second exposure, f/2.8, 50mm, ISO 100
2,759 second exposure, f/22, 18mm, ISO 100