Is "Tentai" a Japanese First name?
 

I know it from "Tentai Kansoku" but I thought maybe it's a Japanese first name?

bump of chicken

anything can be a first name if you want it to be.

It is not. Sure, you could combine different kanji to get the same sound and make a name "Tentai", or even write it the same way as in tentaikansoku... But I would honestly laugh out loud if I spotted someone with that name.

Is "Astronomic" a name in English? Is "Heavenly Body" a name in English?
That will answer your question the best.

Haha, that made me literally lol. Of course, this is assuming that all parents are rational and kind to their kids. My cousin personally went to school with two girls called Coral and Treasure. Surname? Island.

I wish I was making that up.

That`s why I said you COULD give that name - but that doesn`t mean I wouldn`t laugh at someone named "Heavenly Body"
Really, it`s sad that kids have to suffer through names like that.

Because it's like someone approaching you and saying "Hi, my name is Planet!" I can think of many responses to that: "...*snrk*" "Really?" "As in 'Captain'?" but probably not "Wow! Awesome name!"

"Hi, my name is Heavenly-Body Johnson! Nice to meet you! This is my sister, Astronomic Johnson."...

You wouldn`t laugh?