The atmosphere of Neptune is similar to that of Uranus. It is about 80% hydrogen, 19% helium, and 1.5% methane. However the weather activity on Neptune is much more active, and its atmosphere is much bluer than that of Uranus.
If your goal is a legitimate tax deduction, then you must be giving to a qualified organization. Also, you cannot deduct contributions made to specific individuals, political organizations and candidates. See IRS Publication 526, Charitable Contributions, for rules on what constitutes a qualified organization.
Also, keep in mind that you can't write off a contribution to the extent that you get something in return. For example, if you buy a $50 ticket to a fundraising dinner at a church, but the cost of the dinner is $20, you can deduct $30.