Archive Search: Sky Brightness

Observing faint objects is more difficult if the sky is not totally dark. The sky can sometimes be too bright if the Moon is visible, or even worse if the Sun has only just set and we are still in twilight.

By selecting one of these boxes, you can limit the search to observations taken when the moon is up or down, or during twilight.

If you select more than one sky brightness condition, observations with any of them will be selected.

However, if none are selected, all observations will be included in the search.