The entire world is invited to observe the moon Saturday and astronomy-mad Tucson will, of course, participate.

The Planetary Science Institute is teaming with Flandrau Science Center, the University of Arizona’s Lunar and Planetary Lab, UA science students, amateur astronomers and the Girl Scouts to put on a variety of programs from 7 p.m. to 10 p.m.7-10 PM Sat. Oct. 12 at the UA Mall and Flandrau.

The moon, just a day past its first quarter, will be high overhead during the festivities, half lit and half in shadow, for International Observe the Moon Night.

It will be a clear, crisp evening, with temperatures set to drop into the 50s overnight, according to the National Weather Service.

There should be good viewing of the moon through an array of telescopes set up on the mall by the Tucson Amateur Astronomy Association and student groups.

Inside at Flandrau, talks will be given by planetary scientists from the UA’s Lunar and Planetary Lab and there will be art-science activities for the kids.

The planetarium will offer a laser-light show, set to Pink Floyd’s “Dark Side of the Moon.”

It’s all free.