コマ

noun

coma (of a comet)

Astronomical term for the nebulous envelope around a comet's nucleus.

• 彗すい星せいのコマは、太たい陽ように近ちかづくと明あかるく輝かがやく。

  A comet's coma shines brightly as it approaches the sun.

noun

coma; comatic aberration

Optical aberration causing off-axis points to appear as comet-shaped blurs.

• このレンズはコマが少すくなく、星せい像ぞうがシャープだ。

  This lens has little coma, so star images are sharp.