There's an absolutely spectacular celestial gathering happening just above the west-northwestern sky shortly after sunset on Sunday and Monday.

The planets Saturn, Mercury and Venus are in a very tight celestial hug - so close in fact, that Mercury and Venus won't be this close to each other for another 65 years.

If you hold your thumb out at arm's length, it would just about cover up all three planets - that's how close they will be to each other!

Sunday and Monday evenings will be the peak of this conjunction, but the show will continue throughout the week with a little less brilliance on each passing day.

On Sunday night, look for a very bright star in the very low west-northwestern sky around 9:45 and 10 p.m. That is Venus. Less than a tenth of a degree to the lower right will be Mercury. On Monday night, Mercury will be just as close to the lower left of Venus.

You might need a pair of binoculars to separate them, but if you've listened to mom and ate your carrots, you should be able see them with the naked eye.

Mercury and Venus are so close to each other on Sunday and Monday that the Old Farmer's Almanac calls it a "merging star."

Just below Venus and Mercury, a little over a degree and a half away, is Saturn. With a telescope, you should be able to see the murky image of Saturn's rings. Mercury, close by, will be crescent shaped.

You actually won't see much detail of any of the planets because they're so close to the horizon and our view is blurred by Earth's atmosphere. This celestial hugging is pretty much a naked-eye show.

Even though these planets are so close to each other in the sky, they're physically a long ways away from each other. They just appear close because they're nearly in the same line of sight. Currently, Mercury is about 95 million miles from Earth, Venus is 142 million miles distant, and Saturn is almost a billion miles from us.

All three planets will fall out of sight below the western horizon by around 10:30 p.m., but there's still much to see in the summer skies. In fact, right around 10:30 in low western skies, look for a backward question mark lying on its side. That figure is the outline of the chest and head of one of my favorite constellations, Leo the Lion.

At the bottom of the sideways question mark, marking the Lion's heart, is Regulus, the brightest star in the constellation. Regulus is a slightly distant celestial neighbor, about 77 light years away.

If you're new to this column, one light-year - the distance light travels in the vacuum of space in one year - is equal to a little less than 6 trillion miles.

Regulus is much larger than our sun. In fact, it's over four million miles in diameter - five times the sun's girth. Regulus is at the heart of the mighty lion and the rest of the question mark outlines the head.

Look for a triangle to the upper left of the question mark. That's the rear end and the tail of Leo, with the moderately bright star Denebola at the end of the beast's tail. Denebola is 36 light years away. So, the light we see from the tip of Leo's tail tonight left that star about the same time Neil Armstrong walked on the moon in 1969.

There's much more to see in the summer skies. I'll have an entire sky map for the month of July next week in Skywatch.

Mike Lynch is an amateur astronomer and professional broadcast meteorologist for WCCO Radio in Minneapolis and author of the new book, "Pennsylvania Starwatch," available at bookstores and at his Web site www.lynchandthestars.com