[Soliton]

Last time I checked, the moon and the sun were planets.

Check again

[ravingnutter]

First of all, if you are discussing when the Bible was written, we are talking about ancient times, so in order to keep the discussion in historical context, the following applies...

The word "planet" is from ancient Greek "aster planetes" meaning wandering star. For the Greeks, there were seven wanderers:

Sun, Moon, Mercury, Venus, Mars, Jupiter and Saturn. (of course, they used their Greek names: Helios, Selene, Hermes, Aphrodite, Ares, Zeus, Chronos).

So yes, they were considered "planets" in the era when the Bible was written and therefore would technically be part of the "heavens" discussed in the Bible.

But even if you want to frame it in today's terms, due to its size and composition, the Moon is sometimes classified as a terrestrial "planet" along with Mercury, Venus, Earth and Mars. The Earth/Moon and Pluto/Charon systems are also sometimes considered "double planets".