First of all, you have to understand how the meter works. I hope this isn't too basic or sound insulting in any way. I just want to give you a little info as to what the meter is telling you. The meter is designed to give you an exposure that renders your mid tones to a middle gray color. Ok, that is a very simplified explanation and I'm sure someone else can give you more details on this. If you want to see what I mean, set your camera to auto mode, and take a picture of a white wall, and then see what color the picture comes out. Do the same with a black surface and you should get the same middle gray color.

Ok, I just took a look at the specs on the D50. This camera will let you meter 3 ways: 1. 3D Color Matrix, 2. Center-weighted, and 3. Spot.

So wha'ts the differance between these you might ask. Well, this is what Nikon says about 3D color Matrix metering: "The D50 incorporates a 420-pixel RGB sensor for accurate exposure control in all types of lighting situations. By comparing the scene to a built-in database of various lighting patterns, the camera's light meter can accurately produce your best pictures ever." Basically what this means is that the camera is looking at the entire scene, and figureing out what the best exposure would be for that photo. In many cases, this works great. Not so great when you have lots of contrast between light and dark areas tho. Situations like this tend to give you blown out highlights or blocked up shadows.

Center-weighted metering does basically the same thing, only it places more emphasis on the middle of the image.

Spot metering makes the reading based off of a very small portion of the frame. Usually the middle focusing point, but I think some cameras will let you select which focusing point you want to use.

In the situation with the moon, I would use the spot metering mode. This will give you the most acurate reading by eliminating most of the black sky. I don't know how you are able to switch between these modes with your particular camera, but the manual will tell you what to do. I would still bracket your shots even with the spot metering. This means to take a few shots at different exposures, with more exposure, and less exposure to be sure to get what you want.

I see your camera also has mirror lockup, so I would use that as well (with a tripod and cable release.) If you don't have a cable release, the self timer will work. One of the great things about digital is that you can experiment with dif. settings and view your results instantly, and make your changes right on the spot.

As I said, my explanations on exposure are very simplified, so you might want to check out the other posts in the help forum to get a better grasp on it.

Hope this helps.