Celestial Lights
By Phyllis Pitluga June 30, 2006 


Early in July, Jupiter still dominates the sky

During the first half of the month, the bright Moon will wash out fainter celestial lights. However, Jupiter continues to be bright and, with its retinue of moons, it is an ever-changing sight. Those with medium-sized telescopes will be able to witness a unique event when two hurricanes swirling about Jupiter converge on July 4. The Great Red Spot is a huge storm (large enough to hold two Earths side-by-side) that has been viewed since the advent of the telescope nearly 400 years ago. A more recent smaller red spot, dubbed Red Junior, could only swallow one Earth. The drawing together of these storms is being monitored using the Hubble Space Telescope, as shown in the photograph.


Late in July, enjoy the center of the Milky Way

On a dark, clear, moonless night, away from interfering lights, the center of our Milky Way Galaxy glows high in the southern sky about 11pm. It takes about 20 minutes for your eyes to adapt to the darkness before you can really see the details of the faint pathway of light arched across the sky from north to south. The pale white light is coming from stars too distant to see without binoculars or a telescope. The dark regions within this pathway are clouds of gas and dust that are blocking more distant starlight.

Hidden by these dark clouds and buried deep in the center of our galaxy is a super-massive black hole called Sagittarius A*, with matter equivalent to that of three million sun-sized stars. Sagittarius A* is the gravitational hub of our galaxy about which all the rest orbits. Our Solar System makes one orbit about the center every 220 million years. This is our “galactic year.” Scan along the Milky Way with your eyes, binoculars and/or a telescope to pick out luminous patches of gas where new stars are beginning to shine and to detect the globular clusters of old stars bound together. It is a night like this when you can really feel connected with the Universe. 


Sky Calendar, July 2006 




By following the Moon as the biggest and brightest “pointer” in the sky, during July you can identify different planets and bright stars. 

Monday, July 3: First Quarter Moon; Earth is farthest from the Sun at 94.5 million miles 

Tuesday, July 4: Moon passes just above the bright star Spica, a hot star that is 262 light years away and is a multiple-star system

Wednesday, July 5: Moon passes below the planet Jupiter

Saturday, July 8: Moon passes just below Antares, a Red Giant star that is 604 light years away, has a companion star and is a star that irregularly varies in brightness 

Monday, July 10: Full Moon rises at sunset; for the next two weeks the Moon rises about 50 minutes later each night 

Monday, July 17: Last Quarter Moon rises at midnight

Thursday, July 20: Moon passes just above the Pleiades Star Cluster 

Saturday, July 22: Moon passes above Venus

Monday, July 24: New Moon (no Moon because the dark side faces Earth)

Thursday, July 27: Moon passes above Mars

Friday, July 28: Delta Aquarid meteor shower spraying from the southeastern sky after midnight and higher to the south later at night; a minor shower of only about 20 “shooting stars” per hour; moonlight won’t interfere

Phyllis Burton Pitluga is Astronomer Emerita of the Adler Planetarium and Astronomy Museum, Chicago, and is now a San Miguel resident.