Everything you always wanted to know about astronomy
By BRUCE DENNIS SPECIAL TO THE COURIER

On April 24th, a group of astronomers in Switzerland discovered a planet that is very Earth-like. This planet, orbiting another normal star (similar to, but in a different life-cycle than our Sun), has a fairly low mass (like Earth) and is close to the temperatures of Earth (between 30 degrees F and 160 degrees F). It has a mass of about 5 times greater and a diameter of about 50% more than our Earth. It has a year that is about 13 of our days long, and its 'sun' is much cooler and dimmer. The important thing is that it probably has liquid water on it - a prerequisite for life as we know it. Its star is Gliese 581, and is 'just' 20 ? light years away - one of the closest 100 stars. Certainly we'll check it out some day. No doubt, they've already checked us out. Were they disappointed?

Saturn and Venus (the bright

star' that you've been able to see at Sunset at about 45 degrees above the horizon in the West) are very close in the beginning of July. As you remember from last month, the two were very close together during the last couple nights of June. They'll both leave centerstage this month. Jupiter will take over, dominating the summer sky at dusk. Mars will shine (brighter than it has shined for the past 1 ? years) at Sunup. Also at dawn, during the last couple weeks of July (the 1812 Overture with cannons and fireworks is on July 28 in Canandaigua - an advertisement for the RPO), Mercury is easy to see.

During the first part of July, Venus (the brighter of the two bright lights) will pair with Saturn. On July 1st, the pair are only the thickness of a credit card apart. Look for them in the West about an hour after the Sun sets. Venus is approximately 100 times brighter than Saturn because it is much closer to us than the ringed planet. Each night the two set earlier and become further apart until Saturn moves to about 3 fingerwidths from Venus. This will occur by July 7th. Less than an hour after Sunset on the 16th, the crescent Moon passes in front of Saturn. Don't miss this one! Reaching its peak brightness by midmonth, Venus gets even closer (and appears brighter) to us. You'll be able to see (with the aid of a telescope) that the crescent of Venus will go from about 1/3 illuminated to about 1/10. Even though there is less of a crescent, it becomes much bigger (and therefore brighter) during this time.

After the sky becomes dark, Jupiter can be seen in the South as another bright beacon. The best time to observe the giant planet is as soon as the sky gets dark, before the atmosphere gets swirly, and while the object is high in the sky. You will be able to see some details of the planet's surface and its moons.

Around 2 AM in the beginning of the month, Mars rises above the East-Northeast horizon. By August 1st, it rises about 1 AM. As it rises at the end of July, the Pleiades is to its left. Mars will continue to get brighter until December, when it'll be in the sky all night long. You Mars buffs (and the rest of you, John) will really get excited, then.

Mercury is a morning 'star', rising over the East-Northeast horizon about a half-hour before Sunrise. It is only visible during second half of the month. To see this planet best, use binoculars - it'll be too low to use too much magnification.

The Moon is near Mars on the morning of the 9th. A thin crescent Moon is near the Venus- Saturn pair on the 16th. The Earth is the furthest from the Sun in its orbit (aphelion) on the 6th. This is 3.4% further from the Sun than in January; but that's about 6.8% dimmer than in January. Does this mean that we have cooler summers and warmer winters than the Southern Hemisphere? Think about it. The New Moon occurs on the 14th. Happy viewing.