(Not a Teacher)
Pronounce "deer" exactly as you would "dear". However, I'm not too clear on the rules for capitalizing the names of heavenly bodies. If they're by themselves, I think you can get away with leaving the sun, moon, or earth uncapitalized, but if other bodies (with proper names) are mentioned in the same sentence (i.e. Jupiter, Mars, Alpha Centauri, Io, etc.) you should probably capitalize them.