Photographer snaps extremely rare 'green flash' coming from Venus

Looks like chromatic aberration to me! I have lenses that do that, too!

One big clue is the complementary magenta flare 180° away from the green flare. This is characteristic of CA.

So it would be interesting to know what sort of setup Rosén has. If he was shooting with a mirrored telescope, then it's more believable, since those have very low CA. But refracting lenses and telescopes all have CA, to greater or lesser extent.
This is chromatic abberation by the atmosphere. A green flash happens every time the Sun or a planet rises or sets with clear atmosphere. It is there every single time. Any supposed rarity is due to local clouds or haze. You don't even need a water horizon. I've seen it on a sunset behind a mountain range.
  • Like
Reactions: Jan Steinman