Published source

Astral Elf appears in the Astral Adventurer's Guide portion of Spelljammer: Adventures in Space.

Elven identity

The published traits classify the character as a Humanoid and also treat the character as an elf for prerequisites and effects that require an elf.

Astral magic

Astral Fire grants a cantrip choice and Starlight Step provides magical teleportation without being a spell.

Flexible knowledge

Astral Trance reflects the species drawing on shared astral or elven memory by allowing temporary proficiency choices after the trance.

Familiar elven defenses and senses

Darkvision, Fey Ancestry and Keen Senses remain part of the trait package.

Party 1 availability

The Party 1 campaign note restricts this option to characters connected to that campaign's observatory storyline. This is a campaign-specific restriction, not part of the published Spelljammer species.