Lunar "X"

[Towa]

Last night I managed to observe the Lunar "X" feature.

To help me plan future observations of this feature, how many

hours before first quarter does the feature first become visible and

how many hours does it last?

[Talitha]

I just watch Albategnius and Klein. When the terminator is advancing westward across these craters, it's almost showtime for the X.

For a rough time guesstimate, i simulate the movement of the terminator in the free Virtual Moon Atlas by manipulating the daily/hourly buttons on the Ephemeris tab.

Try downloading the 'Light' or 'Expert' version... 'Pro' is overkill unless you're really into lunar geology.

EDIT...

Sorry, i forgot to mention... the X is visible for several hours.

[Towa]

Thanks Talitha, I will download the light version.