Moon:
New Moon: April 1.
Star Gaze (April 4):
Sun: sets at 6:49pm
Moon: (illuminated 6%) sets at 9:42pm on the night of the Gaze. (Per Megastar)
Jupiter & it's moons: (1) Jovian moon Ganymede is transiting Jupiter's disk at nightfall and egresses transit at 7:09 pm. Its shadow begins transit at 8:14 pm and ends at 11:53 pm. (2) Io reappears from eclipse at 7:39 pm. (3) The Great Red Spot (GRS) becomes visible about 10:30 pm, crosses the planet's meridian at 12:05pm, and disappears about 1:30am. (Per the "Planets202" program and S&T) . You need only about a 6" reflector to see this stuff!Planets:
Mercury: Mid-month is a good time to observe. It will be dimmer than earlier in the month, but will be higher in the sky. (Regretfully, Mmercury's transit of the Sun on May 7th ends an hour before sunrise for us in WNC.)
Venus: Low on the horizon all month, not a good time to observe.
Mars: Quite small, about 10" diameter. It doubles in brightness this month, to Magnitude 0.0. (The red planet is getting ready for it's late-August extravaganza: the closest approach to Earth in the last 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: Hanging on at Magnitude 0.1, but still a good view early in the evening. Looks quite 3-D at this time (shadow of planet's disk is cast to the side, onto it's rings). Realize the geometry here, and you can "feel" the sun under your feet, casting that shadow. Also, the rings reach maximum tilt of 27 degrees this month, making it easier to see detail in the rings.
Jupiter: Dominates the sky, bright (mag -2.2) & almost directly overhead at nightfall (contrast this with Mars being only 40 degrees above the horizon in August). Getting dimmer, but still a good view. It's just 1.1 degrees from the Beehive open cluster in early April. It looks great in binoculars or a very low-power, wide-field telescope view. Both will show the Jovian moons and the cluster in the same field of view. Remember than the line of Jovian moons is showing you the plane of the solar system. (See "DSO" objects below)
Asteroids: Vesta is mag 5.9 when April arrives, but is at mag 6.4 by the end of April. So look for it naked-eye, especially early in the month! It won't be as bright again until May 2007. 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):
Beehive Cluster (M44, open cluster) in Cancer - See Jupiter, above. See S&T article
Tau Hydrae (Double 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 (Double 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 parsecs. 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: 10h 35.0m R.A. 8 deg 39' Dec).
40 Sextans (Double 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 the galaxy is 69x further away (but in another direction). (Location:10hr 49.3' R.A. - 4 deg 01' Dec)
Highlights:
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.)
Comet C/2002 Y1 (Juels-Holvorcem) was discovered on December 28, 2002 by 2 amateur astronomers on an image taken thru a 120mm (4.7 inch) f5 refractor!!! You can see it in the late morning sky until mid-April. It's at mag 5.3. See S&T article
Lyrid meteors on April 22. 10 to 20 meteors per hour at it's peak. Moon is in last quarter, sets at 11:42 pm on the 22nd. The shower's peak is about 16:30 UT (12:30 PM EDT), so they are possibly best observed the previous morning. At that time Lyra will be in the east. The peak is short, though, so expect to see substantially less than 10-20 per hour. (Most of us will "pass" on this shower.)
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The Big Picture:
Take a look at an all-sky map that has the Messier objects on it:
6 hr R.A. (passes overhead on winter evenings; low in the west on April evenings): OPEN CLUSTERS in the sky north to south (Auriga to Pupis).
12 hr R.A. (passes overhead on spring evenings; in the east late on April evenings): GALAXIES in the sky north to south (Ursa Major to Virgo).
18 hr R.A. (passes overhead on summer evenings; in eastern sky in late morning hours in April): GLOBULAR CLUSTERS in the sky north to south (Cygnus to Sagittarius).
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Club Stargaze:
The April stargaze is Friday, April 4, 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, 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