Friday night’s full moon, the snow moon, will be shaded slightly by the Earth. It is a penumbral lunar eclipse and it is not like any one of the lunar eclipses you’ve seen in the past.

This is an eclipse you would easily miss if nobody told you about it. The eclipse begins at 6:14 p.m. but you really won’t notice much until many minutes later. Mid-eclipse is at 7:44 p.m.

We recommend going out at the start of the eclipse, looking again an hour later for a subtle difference and then again at 7:44 p.m. when the edge of the bright full moon is slightly shadowed. This is not the eclipse your science teacher told you about when you were growing up as a child. This is a titillating taste of big things that almost happen in astronomy. Big planets and moons do many things, and they “almost” do things too.

For those looking for a really good total lunar eclipse, when the moon slips into the full shadow of the Earth and turns a faint orange like a pumpkin, you have a long wait to see one from Martha’s Vineyard. The next full lunar eclipse that we can watch here together will take place on Jan. 20, 2019, almost two years away. The long wait for the grand performance makes Friday’s show a little more appealing.