Is Sora no Otoshimono anime non-canon?

Question

I was told that this anime is non-canon, but there are things from the anime that are just as the same as the manga.

Answer 1

Strictly speaking, the manga is the canonical source since it's the original work. However, the anime adaptation is also considered as an original work based on the manga. It means, while the anime follows the general theme, there are some changes and it includes original stories.

The differences between the TV broadcasted anime's 1st & 2nd season (not including the DVD version) and the manga according to Japanese Wikipedia:

• In the manga, Mikako rarely appears in serious situations. However, in the anime, she appears more often including in serious situations. She introduces herself as Eishirou's "3rd assistant" in S1E9 (though, in the beginning of S2E4, she says she loses interest and offers a resignation letter), actively participates in Tomoki and his group's actions, gives guidance gently to Astraea who is troubled because she doesn't have place to live, and so on.
• Nymph's first appearance is not in "Ikaros' attack" (S1E8), but in "Sea bathing" (S1E6).
• In the manga, Astraea doesn't transfer to Sorami Middle School, but she does in the anime.
• Since the TV broadcast regulation tries to avoid Tomoki's sexual harassment in the manga, there are some changes on the scene where he transforms into Tomoko in S2.
• In the second-half development of first Chaos' battle (around S2E8), the scene where the author didn't include in the manga is changed.
• In the manga, the scene where Nymph's wings grow back after hearing Tomoki saying "I'll be the master" is after first Chaos' battle. However, in the anime, it occurs in the middle of second Chaos' battle.
• Regarding Chaos' second appearance, since the development of the manga and anime's 2nd season almost happened at the same time, it becomes an anime original story.