I want to take some astrophotography shots of objects in the sky while not keeping the moon in the shot. I have read in a few places that you need essentially a moonless sky to do so. Does that mean that I have to wait for a new moon phase or for the moon to set? Or does it mean that I just don't want the moon in my frame? I'm traveling to an area with very little light pollution, so I would like to take some star trail shots, but am unsure what I can do since the moon will be at around 1/2 phase.
It will actually depend on your humidity! As the air gets more humid there is more water vapor in the air and this helps scatter the bright moon light, brightening the dark black sky.
However, to answer your question, if you wait until the moon is well set you should be fine. You may find it easier to wake up early rather than stay up late.
Dew can be a real problem. You are pointing a piece of glass at the sky as the temperature drops. A homemade cardboard dew shield is quite effective. Just wrap a cylinder around the lens. The height of the cylinder should be about the width of the lens. Of course, if you are shooting wide angle then this could block parts of the image. But if you dew up, well, all the image will be blocked.
Keep the lens pointing down at the ground when you take a break. Once you dew up it is difficult to remove it. A portable hairdryer in the car's lighter can do it, but preventing it is much easier.
A cable release would be awesome.
A practice BEFORE you go to your dark site.
Oh, and wear warm clothing.