Astronomy Club of Asheville, NC

July - 2003

"The fairest thing we can experience is the mysterious. It is the fundamental emotion which stands at the cradle of science. He who knows it not and can no longer feel amazement, is as good as dead" (Albert Einstein)

MOON:
New Moon: July 29

STAR GAZE: (July 25):
Sun: sets at 8:39pm
Moon: (illuminated 11%) sets at 6:05pm on the night of the Gaze. (Per Megastar)
Jupiter & it's moons: Jupiter sets at 9:49pm, too low to observe.

PLANETS:
Mercury: Visible in late July, but very close to the horizon.

Venus: Low in the east just before sunrise.

Mars: Quite small, grows from 16" to 22" diameter this month, and increases from magnitude -1.4 to -2.3. (The red planet is getting ready for it's late-August extravaganza: the closest approach to Earth in at least 2000 years! Unfortunately, since Mars is south of the ecliptic, it will be only about 40 degrees above the southern horizon when it crosses the meridian each night, so Earth's atmosphere will blur the image a bit here at 35.5 degrees north. To get Mars higher in the sky for a sharper view, I recommend a quick trip to southern Florida in August. Be sure our rooms are air conditioned!)

Saturn: Rises the sun, but too low to observe well.

Jupiter: Sets about an hour after the sun, so not a good time to view.

Asteroids: Vesta (in Virgo) is mag 7.4 when July arrives, and is at mag 7.6 the end of July. You'll need binoculars to see it. Vesta is the second largest asteroid (530 km) this side of the Kuiper Belt, but is by far the brightest due to it's 42% albedo (reflectance). Ceres is the largest (933 km), but has an albedo of only 11% and reaches only mag 7. See April S&T, p102 for a finder chart.

DEEP SKY OBJECTS (DSO's): (Not the biggest or best, but interesting)
M24, NGC6603, B92, B93: The Earth is located on the inner edge of the Orion-Cygnus Arm of the galaxy. When we look towards Sagittarius, we are looking across a void at the Sagittarius-Carina Arm (6,000 light years (ly) away) and towards the center of the galaxy 27,000 ly away. Our view to the galactic center is blocked by dust, but we can see through a gap in the Sagittarius-Carina Arm to the Norma Spiral Arm 14,000 ly away. In this gap appears the star cloud M24 and its several associated objects. M24's is 530 ly long and is easily visible to the naked eye.
NGC6603: A small (5') but dense open cluster of faint stars, easily seen in scopes 8" or larger. True size 20 ly. (Location: 18hr 18.4m RA -18 deg 25' Dec, in Sagitarrius)
B92, B93: Dark clouds of dust that obscure the stars beyond. B92 is one of the most easily seen dark nebulae, about 15'x10' in apparent size.
M24 itself appears very large (95'x35', 3 times the size of the full moon) and is best viewed through a wide-field telescope. Keep in mind that what you are seeing is twice as far away as the Swan Nebula (M17) to the NNE and the Triffid Nebula (M20) to the SW.

HIGHLIGHTS:
July 8: Venus at it's greatest northern declination for the year.
July 11: Mercury furtherest north of the ecliptic for the year.

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THE BIG PICTURE: Each chart below covers a very wide area of sky, roughly from eastern horizon to western horizon. Constellations are green stick figures. The dividing line between constellations are dashed blue lines. The purpose is to show the large scale structure of the night sky: why certain types of objects are visible in certain areas of the sky.

1. Above: 6 hr R.A. (passes overhead on winter evenings; not visible in July): OPEN CLUSTERS in the sky north to south (Auriga to Pupis). Open Clusters are generally within the arms of the galaxy and are roughly co-located with the Milky Way. They are plotted as tan circles above. You are looking away from the center of the galaxy. (Note: all types of objects are labeled, not just open clusters.)

2. Above: 12 hr R.A. (passes overhead on spring evenings; sets at sunset in July): GALAXIES in the sky north to south (Ursa Major to Virgo). They are plotted as blue ovals in the chart above. At 9:00pm during mid-June, the Milky Way is rising in the east. Just to the west of the zenith is the North Galactic Pole, in the constellation Coma Berenices. In southwest Coma Berenices happens to be the heart of the Local Supercluster of galaxies. Many of these galaxies are visible in medium-sized telescopes.

3. Above: 18 hr R.A. (passes overhead on summer evenings; overhead at 10:30pm in mid July): GLOBULAR CLUSTERS (yellow cross inside a circle) & PLANETARY NEBULAE (blue circle in a cross) in the sky north to south (Cygnus to Sagittarius). The lower-middle of this chart is towards the center of the Milky Way galaxy.

Charts created using Megastar
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CLUB STARGAZE:
The July stargaze is Friday, July 25, 2003. You can check the Yahoo group for AstroAsheville (or call Tim Barnwell @ 251-0040 or John Chappell @ 251-1933 x17 (before 5:00) or 667-9268 (after 5:00)) for a go/no-go decision and to verify location.

Blue Ridge Parkway Information Line is 828-298-0398 and go to Road Conditions on the menu.

CLUB MEETING:
The club meeting is the first Thursday of every month, at 6 p.m. at Sim’s Group located at 230 Short Coxe Ave., Asheville, NC.

Happy Starwatching! Dress Warm!

(Much of the above info derived from Sky & Telescope and Astronomy magazines, Ottewell's Astronomical Calendar, The Night Sky Observer's Guide, Megastar 5.0, Planets202, the ol' Miller Planesphere, and a little (very little) common sense.)