While you are correct that I misunderstood you, and thought you were talking about "planet", astronomers use "celestial body" to include the Earth, and have done so since the 1800s. Your comment started "Technically", so I believe you mean to use the astronomy definition, in which case your statement "Earth, not being in the night sky, is not celestial" is using non-technical language where I expected it to use technical language.
> Titan has long fascinated astronomers as the only moon known to possess a thick atmosphere, and as the only celestial body other than Earth to have stable pools of liquid on its surface.
> Their [the Chaldeans] ideas of the earth as a celestial body were also crude and imperfect.
The second from "A system of universal geography : or, A description of all the parts of the world, on a new plan, according to the great natural divisions of the globe, accompanied with analytical, synoptical, and elementary tables", vol. 1 (1847) at https://archive.org/stream/universalgeograp01maltuoft#page/n... :
> Theory of Geography. Of the Earth, considered as a celestial Body, and in its relations to the other celestial Bodies.
> 5thly-That the Earth, like every other celestial body, moves with accelerated velocity during the perihelion, and ...
You are also right that "celestial body" in popular use is often treated as a synonym for "heavenly body". This is a pre-Copernican viewpoint, expressed in 1 Corinthians 15:40 as "There are also heavenly bodies and there are earthly bodies; but the splendor of the heavenly bodies is one kind, and the splendor of the earthly bodies is another."
However, you emphasized the technical definition, not the general culture use.
P.S. Did you mean "planets revolving around the Sun" instead of the Earth? Also, earlier you wrote "Earth, not being in the night sky, is not celestial", but I'll point out the Sun is also not in the night sky; is it also not celestial?
Two modern examples of how "celestial objects" includes the Earth are https://www.iau.org/static/archives/releases/pdf/iau0915.pdf :
> Titan has long fascinated astronomers as the only moon known to possess a thick atmosphere, and as the only celestial body other than Earth to have stable pools of liquid on its surface.
and http://astroedu.iau.org/activities/blue-marble-floating-empt... :
> These astronauts were the first people to ever orbit a celestial body other than the Earth, ...
Now, three historical examples, the first from Youth's Book of Astronomy (1839), https://books.google.com/books?id=qZc-AQAAMAAJ&dq=celestial%...
> Their [the Chaldeans] ideas of the earth as a celestial body were also crude and imperfect.
The second from "A system of universal geography : or, A description of all the parts of the world, on a new plan, according to the great natural divisions of the globe, accompanied with analytical, synoptical, and elementary tables", vol. 1 (1847) at https://archive.org/stream/universalgeograp01maltuoft#page/n... :
> Theory of Geography. Of the Earth, considered as a celestial Body, and in its relations to the other celestial Bodies.
Since "considered as" isn't as strong as "is", here's the third example, from "Astronomy simplified" (1838), https://books.google.com/books?id=cWAEAAAAQAAJ&dq=celestial%...
> 5thly-That the Earth, like every other celestial body, moves with accelerated velocity during the perihelion, and ...
You are also right that "celestial body" in popular use is often treated as a synonym for "heavenly body". This is a pre-Copernican viewpoint, expressed in 1 Corinthians 15:40 as "There are also heavenly bodies and there are earthly bodies; but the splendor of the heavenly bodies is one kind, and the splendor of the earthly bodies is another."
However, you emphasized the technical definition, not the general culture use.
P.S. Did you mean "planets revolving around the Sun" instead of the Earth? Also, earlier you wrote "Earth, not being in the night sky, is not celestial", but I'll point out the Sun is also not in the night sky; is it also not celestial?