I'd strongly recommend that book that Jim posted a link to then.
Photography is all about getting exposure right, which mean letting the right amount of light into the camera. Too little light and the image is too dark, too much light and the image is too bright. Bright white with no detail means too much light is getting in and your image is overexposed. In this case, if the moon is small in the frame with a predominantly black sky your camera will meter more for the black meaning that white's will over expose. For moon pics I spot meter on the moon itself meaning that the moon should be properly exposed (you may have to tweak it slightly), it doesn't matter if the sky is underexposed as it's black anyway.
With regards to metering, cameras meter the light to achieve what is neutral grey. You can think of this as mid way between the whitest whites and the blackest blacks. If you have a black scene the camera will try to make this grey and so over expose the image, likewise if the scene is white it will try to make the white grey and underexpose the image.
Read that book, it will start to make more sense after that.
data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7 me too - I bought an older version which was mostly based on film was good but the more recent revision that is digital focused is a great read.
Pretty sure the pdf is available online with a quick google search - scripd or similar springs to mind....
I used 1/160 at f5.6 and iso 100. 400mm lens on a crop sensor of 1.6 so effective focal length was 640mm
https://www.avforums.com/attachments/0n7a9820-3-jpg.1020368/
Crackin detailed shot
Nice shot. Obviously the light from the moon varies in intensity but most of my shots have been circa ISO 100, 1/160, f8
The moon will have the same exposure as any mid to darkish grey rock lit by the full sun near enough as that is what it is.
There are other factors that come into play such as atmospheric conditions.