Everything you always wanted to know about astronomy
June
By Bruce Dennis

Bruce Dennis is a retired science teacher from Haverling High School.

Way back in 1932 (75 years ago), it was thought by various astronomers and quoted by some, that "most asteroids are of no particular interest … ." But today, we fear that one of these thousands of orbiting (around the Sun) rocks will collide with the Earth, causing a nuclear winter (black sky) for years, causing temperatures to drop a lot, causing no food to grow to feed the unsheltered and sheltered animals (us), and causing mass extinction planet-wide of nearly all plants and animals. "… no particular interest …"? I think this is far from the truth. We've learned a lot since 1932. We've learned that asteroids are not merely chunks of rock that are left over from the collision of a couple of other planets that orbited the Sun outside Mars' orbit, but we've grown to respect their motion and position - our future may depend on them. Now that you're scared and sitting on the edge of your seat, let's look at the planets and save the gloom and doom for the politicians. As novice astronomers, we can witness the birth of stars and the motion of the planets.

During June, Jupiter is very active and changing as we watch. Mercury will glow in the west-northwest at sunset. Venus, found in the West, joins Saturn for a spectacular conjunction during the last week of the month.

Mercury, growing dim quickly, is low in the West at sunset during early June. It is to Venus' (the bright 'star' in the west at sunset) lower right. It'll be at Gemini's feet about June 1st, looking west-northwest. Venus, the brightest beacon in the West (about 25 degrees above the horizon) is setting rapidly. It is only about 15 degrees above the horizon by July 1st. On June 1st and 2nd, Venus lines up with Castor and Pollux (the heads of Gemini). On the 12th and 13th, Venus passes through M44 (the Beehive Cluster).

Saturn is on the move. It gets closer and closer to Venus throughout the month: about 20 degrees apart on June 1st to less than the thickness of a credit card apart on June 30th. On this date, telescopes will show the 36% illuminated crescent of Venus along with the rings of Saturn. Saturn is about 13 times further from the Sun than Venus, so as you would expect, it's much dimmer.

Jupiter rises at about sunset (after the 6th) and remains visible al night long for all of the month. It is very low in the sky, making it very difficult to view with a telescope all month. Remember, the closer an object is to the horizon, the more unstable atmosphere we must look through and the less crisp is our view. For the best telescopic views, look through the telescope about 1 AM, or when Jupiter is at its highest position. Look at the Great Red Spot and the bands of swirling gas at Jupiter's Equatorial Zone. Jupiter is in retro-grade motion - from night to night it moves to the West. This motion is caused by Jupiter's and Earth's revolution around the Sun. Their changing positions causes an apparent change in direction of their movement. In a few weeks, Jupiter will once again, move toward the East.

Mars, although it is still small, gets higher and brighter each morning as it rises (in the East). It's been getting smaller every month for over a year. It's about time it started getting bigger! On the 18th, the Moon will totally cover (occult) Venus in the Middle East. On the 27th and 28th, the Moon will shine near Jupiter. A full moon occurs on the 30th. This is the 2nd full moon, or Blue Moon, of the month. On June 21st, the Summer Solstice occurs - when the direct rays of the Sun reach the Tropic of Cancer (the furthest North they'll fall). This is the first day of Summer in the Northern Hemisphere. It is also the longest daylight period of the year (almost). The nights will be getting longer after this date! Happy viewing.