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Astronomy Club of Asheville, NC

April - 2004

"In a society that has somewhat turned away from traditional mysteries and wonders, the cosmos is always full of mysteries and wonders ... I think this is something primal in our software .... From the beginning of time, people looked up in the sky and were awed by it." Jack Horkheimer

MOON:
Full Moon: April 5
New Moon: April 19

STAR GAZE (April 16):
Sun: Sets at 8:06pm, astronomical twilight ends at 9:37pm and begins at 5:29am the next morning. The Sun rises the next morning at 6:57am. Between astronomical twilights, we get about 8.1 hours of darkness.

Moon: (illuminated 7%) The Moon sets at 5:25pm.

Jupiter & it's moons: Jupiter is 36 degrees above the eastern horizon at sunset. There are no Jovian moon events tonight or tomorrow night. Jupiter culminates (is highest in the sky) at 10:38pm.

Saturn: Saturn is 74 degrees above the western horizon at sunset. The "star" located about 3 ring diameters away to the north-east is really the moon Titan. Saturn reached opposition on December 31 and it's moving further and further into the western sky, to be lost in the sun's glare in a few months. The rings appear very tilted to our view at this time, so Cassini's Division and other ring features are visible.

Asteroids: Ceres (in Gemini, less than 2 degrees from the star Castor) is high in the sky at sunset on the night of the gaze. You can see it in binoculars as a faint, star-like object at magnitude 8.5.

SOLAR SYSTEM:

Mercury: Very good showing above the western horizon the first week of the month.

Venus: Very good showing this month in the evening sky. Venus sets at about midnight! It is now so bright and far from the sun, that it can be seen in daylight if you know exactly where to look. Use the near-by moon on the morning of April 23 to locate it.

Jovian Events: (Verify these time's thru another source. I've make mistakes before!)

April 6 (Tues): The transit of Io begins this series of events. We should be able to watch Io's shadow catch up with and pass Euorpa. Also, Io's shadow will be a good landmark to find Europa itself.
11:11 pm    Io begin transit
11:23 pm    Europa begin transit
11:55 pm    Io's shadow begin transit
12:45 am    Europa's shadow begin transit
  1:26 am    Io ends transit
12:07 am   Great Red Spot (GRS ) on meridian

April 7 (Wed): Io's shadow ends transit at 8:39pm; Europa reappears from eclipse at 10:18pm; Ganymede reappears from eclipse at 1:31am on the 8th. (When a moon reappears from eclipse, it seems to just appear from nowhere, because it is coming out of Jupiter's shadow. This is different from an occultation, when the moon goes behind the disk of Jupiter.)

April 13 (Tues): A similar event sequence begins at 12:58am, but Io's transit ends about 15 minutes before Europa's shadow begins transit.

April 20 (Tues): Io & Europa are on either side of Io's shadow about 4:35am. Io's shadow is on Jupiter's meridian at this time.

(You need only about a 6" reflector to see transits! Begin to look for a Jovian moon in transit about 30 minutes before it leaves Jupiter's disk, or just as it begins to cross in front of Jupiter's disk. Once the moon gets more towards the middle of Jupiter's disk, the tiny, sharp, white disk of the moon is much more difficult to detect. In contrast to this, the shadow of the moon is visible all the way across Jupiter's disk. This is because of the greater contrast between the dark shadow and the bright disk of Jupiter.)

5 Planets are visible at once, early in the month. S&T article

DEEP SKY OBJECTS (DSO's)  (Not the biggest or brightest, but interesting):

Tau Hydrae (Binary stars): a colorful F6 (yellow) & K0 (pink) pair, 66" separation; Magnitudes 4.6 & 7.2. Their distance from Earth is 17 parsecs (55 light years) & true separation is 1,100 a.u. (27.5x that of our sun and Pluto). (Location: 9h 29.1m R.A.   -2 deg 46' Dec)

49 Leonis (Binary stars): a close pair of white-hot A2 stars at 2.5" separation; Magnitudes 5.8 & 8.5. Their distance from Earth is 82 parsecs, & true separation is at least 200 a.u.. This makes their separation only 5x that of our sun and Pluto (40 a.u.). No beautiful color contrast here, but easy to imagine the size of the Solar System placed here. Just sit there at the eye piece and imagine the sun in place of the primary star, and Pluto 1/5 the way to the other star. Then sit there and contemplate a while longer. (Location: 1 degree SE of Rho Leonis, 10h 35.0m R.A.  8 deg 39' Dec).

40 Sextans (Binary stars) : a closer pair of type A2 stars, white & grayish white, at 2.2" separation; Magnitudes 7.0 & 7.8. Their distance from Earth is 120 parsecs, & true separation is at least 260 a.u. This makes their separation 6.5x that of our sun & Pluto. This pair is the most distant of our trio, but the center of our galaxy is 69x further away (but in another direction). (Location:10hr 49.3' R.A.    - 4 deg 01' Dec)

HIGHLIGHTS:

Partial Solar Eclipse on April 8: See this Sky & Telescope article. As seen from Asheville it begins about 5:42pm and ends about 6:54pm. About 15% of the Sun's diameter will be covered.

May Day, or Beltane: One of the 4 "cross quarter" days in the standard calendar, it marks the beginning of Solar Summer in the old agrarian calendars. This is the quarter of the year with most sunlight (May,June,July), as opposed to the quarter that is hottest (June,July,August). See this Weather Almanac article. (Begin celebrating at sundown on April 30, as did the ancient Celts. Their days began and ended with sunset.)

Lyrid meteors on night of April 21 & morning of April 22. The number of meteors and length of the peak varies. The ZHR averages 18. The Moon sets at 8:oopm this night, making for god viewing. The shower's peak is about midnight. At that time Lyra will be rising.

CLUB STARGAZE:
You can check the AstroAsheville Yahoo group (or call Tim @ 251-0040 or John @ 251-1933 x17 (before 5:00) or 667-9268 (after 5:00)) for a go/no-go decision and to verify location.

CLUB MEETING:
Indoor club meetings are usually the first Thursday of every month, at 6 p.m. in the Sim’s Group offices (230 Short Coxe Ave., Asheville, NC.)

Happy Starwatching!   Dress Warm!
Blue Ridge Parkway Information Line is 828-298-0398

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(Much of the above info is derived from Sky & Telescope magazine, Ottewell's Astronomical Calendar, The Night Sky Observer's Guide, Burnam's Celestial Handbook, Megastar 5.0, Planets202, the ol' Miller Planesphere, and a little (very little) common sense.)
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Archived Monthly Sky 2002: Feb Mar Apr May June July Oct Nov Dec
Archived Monthly Sky 2003: Mar Apr May June July Aug Sep Oct Nov  Dec
Archived Monthly Sky 2004: Jan Feb Mar