A partial lunar eclipse, and a rare Venus transit

And the hits just keep on coming. We observed -- albeit on the computer -- the annular eclipse of the sun on May 20, and now there are two more spectacular celestial events in the offing for our viewing pleasure.

Although, one of them will be better viewed using on-line remote telescopes.

First up is a partial lunar eclipse. A lunar eclipse occurs when a full moon passes through Earth's shadow. A lunar eclipse can only happen during a full moon.

That will be on Monday, June 4. Unfortunately, it will start just before sunrise.

Those of us who reside in Southwest Nebraska and Northwest Kansas will not see all of the eclipse. The first noticeable "bite" of Earth's shadow showing on the lunar surface will be at about 4 a.m.

The eclipse will progress for a little over an hour when the moon will set and be lost to our view. The partial eclipse will cover only the bottom half of the moon anyway.

The next event is the biggie for us astronomical types, Venus will transit, or cross in front of, the face of the sun, on Tuesday, June 5.

This is an extremely rare event. The last transit of Venus was in 2004, the next will be in 2117 followed by another one in 2125. Previous transits were in 1761, 1769, 1874, and 1882.

The best opportunity to view this event is to point your favorite web browser to www.slooh.com and use the robotic telescopes. Live on-line coverage will start at about 4 p.m. MDT.

As with the moon during the lunar eclipse, the sun will set from our view before the total transit is over.

Again, I must post here the traditional warning about viewing the sun directly or without proper visual protection.

Alas, I will not be in Southwest Nebraska for this event as I was in 2004. Duties require that I stay in Colorado and view the event from there -- mostly on my computer or cell phone.

Another planetary transit will happen on May 9, 2016, when the smallest planet, Mercury, will cross in front of the sun. A transit of Mercury isn't nearly as rare an event as the Venus transit. They happen several times a century.

In the 1700s and 1800s much attention was paid to the transits of Venus as many astronomers set out to locations around the world in an attempt to observe the event.

By comparing the times of the beginning and ending of the transit times from the wide-spread locations it would be possible to establish the exact Earth/Sun distance.

SKY WATCH: Full moon and partial lunar eclipse June 4. Thursday, May 31, an almost-full moon will be very close to Saturn and Spica high in the south about an hour after sunset. Spica will be quite close just above the moon while Saturn is above both of them. On Sunday, June 3, the moon will have moved further east snuggling up with the bright star Antares in the constellation, Scorpius. Our old friends in the Summer Triangle are peeking above the eastern horizon shortly after sunset and will continue to rise higher each day to take their place as the dominant constellations of the season.

NEXT WEEK: More astronomical blathering.