There will be two more very exciting celestial events taking place this month, but only one of them will be visible for us in New England. The annual Delta Aquarid Meteor Shower will peak during the morning hours of July 28. This shower actually begins around the middle of July and blends right into the famous Perseid Meteor Shower, which starts at the end of July and peaks on August 12.
Caused by Comet Machholz, you can expect around 15 to 20 Delta Aquarids per hour that morning. The moon will be first quarter and will set around midnight. Meteor showers are usually better after midnight, anyway, since that is when the earth is spinning directly into the meteors, like snowflakes on the front windshield of your car during a snowstorm. The whole earth can be seen as a little spaceship continually orbiting the sun at 18.6 miles per second, or 67,000 miles per hour.
I remember seeing Comet Machholz, the 10th comet discovered by Don Machholz of California, in the morning sky with binoculars near the Pleiades in January 1996. These meteors will appear to originate from a point in the sky in Aquarius low on the southeastern sky just above the 17th-brightest star in the sky named Fomalhaut, located 25 light years from Earth.
When you look at that star this summer, remember that the very first planet ever seen directly in visible light was just found orbiting this star using the Hubble Space Telescope late last year. It is a Jupiter-sized planet that orbits Fomalhaut at a much greater distance than Jupiter is from our sun since it takes that planet, called Fomalhaut B, about 872 years to orbit its parent star. It was found just inside the edge of a huge disk of dust, and it was predicted to exist there for a while, since they studied this star for eight years before they finally found its planet in visible light.
The other major event will be a total eclipse of the sun. That will happen July 22 over India and China. The narrow shadow cone of the moon will sweep across the earth that day starting just north of Mumbai, India, continuing over Bhutan and across southern China exiting in Shanghai, the biggest city in China with 20 million people.
Bhutan, located on the rooftop of the world next to Nepal, is a very interesting country that has successfully balanced modernization with preserving ancient culture and the environment under the guiding philosophy of Gross National Happiness. It's the only country in the world to actually measure this elusive human quality.
At least one member of our astronomy club, The Astronomical Society of Northern New England, will be going to China for this eclipse, so I will update you next month on what they experienced. Try to catch this eclipse live on the NASA channel or a live feed on the Internet.
I remember seeing the last total solar eclipse live on the NASA channel from Mongolia at 7 a.m. last Aug. 1. Actually being there to experience a total eclipse of the sun and physically standing in the shadow of the moon, our only natural satellite is one of the most exciting and memorable experiences in astronomy anyone could ever have. The next total solar eclipse happens on July 11, 2010, right over Easter Island in the south Pacific, and the next one in this country doesn't happen until Aug. 21, 2017.
Saturn is beginning to sink into the western horizon and will be setting by 10 p.m. Through a telescope you will notice that the angle of its rings is getting ever thinner, reaching just 2 degrees from horizontal by the end of the month. Look for a slender waxing crescent moon to glide under Regulus and Saturn about 30 minutes after sunset from July 23 to 25.
Jupiter begins the month rising by 11 p.m. and ends the month rising by 9 p.m., just after sunset. The King of the Planets will rise at sunset by the middle of August, when it reaches opposition. Jupiter continues to get a little brighter and closer each night until that time. Notice that you can see its four large Galilean moons with just a pair of good binoculars.
The rest of the planetary action takes place in our morning sky about one hour before sunrise. Orange Mars can be seen just below the Pleiades and brilliant Venus is below and to the left of our other neighbor, and just to the left of Aldebaran, an orange star in Taurus. Venus is 100 times brighter than Mars and over 3 times as large in our sky.
However, Mars is slowly getting closer and brighter and Venus is getting less bright and farther away, even though it is getting more illuminated by the sun now, similar to a waxing gibbous moon. Watch the drama in the morning sky between July 17 and 19 as a waning crescent moon drifts through the Pleiades right above Mars and Venus.
Friday. The earth is at aphelion or farthest from the sun at 10 tonight. Our orbit around the sun traces an elliptical shape, but it is not very different from a circle since we will be just 3.3 percent farther from the sun now than we are in January. Our seasons are caused by the 23.5-degree tilt of the earth and not our distance from the sun. The waxing gibbous moon will pass very close to Antares tonight. If you were in Hawaii, you would see the moon cover this bright star tonight around midnight. Antares, a red supergiant star, is the 16th-brightest star in the sky and one of the largest stars in our whole galaxy of 200 billion stars. Antares is 700 times the diameter of our sun and 10,000 times brighter than our sun. Antares is 600 light years away, but if you could place it were our sun is in the sky, the orbit of Earth and even Mars would be inside the star below the surface.
July 7. Full moon is at 5:21 a.m. This is also called the Hay or Thunder Moon.
July 9. Jupiter will be near the moon tonight and the next night in the constellation of Capricornus. Through a small telescope you can see Neptune just to the north-northwest.
July 15. Last quarter moon is at 5:53 p.m.
July 16. On this day in 1994, the first fragment of Comet Shoemaker-Levy 9 hit Jupiter. After that 20 more mile-wide fragments plowed into Jupiter's gas surface during the next six days, one hitting about every six hours. I watched through a telescope as five of those 21 fragments hit Jupiter, but since they actually hit on the far side of Jupiter, I could not see them until about 30 minutes later as they rotated into view. One of many surprises that these impacts created were the large and easily visible (even in a small telescope) earth-sized black spots that remained visible for many months after the original impacts.
July 21. New moon is at 10:35 p.m.
July 28. First quarter moon is at 6 p.m. and the Delta Aquarid meteor shower peaks.