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O Star (the fairest one in sight),...
Say something to us we can learn
By heart and when alone repeat.
Say something! And it says, 'I burn.'
(Robert Frost)
MOON:
New Moon:
May 1 and May 31
Total Lunar Eclipse: May 15: 1.Moon enters umbra,
10:03pm 2.Moon completely in umbra, 11:14pm
3. Mideclipse, 11:40pm 4.Moon begins exit of umbra, 12:06am
5. Moon completes exit of umbra, 1:17am (Times are EDT)
See S&T
Article
STAR GAZE: (May 2):
Sun: sets at 8:16pm
Moon: (illuminated 2%) sets at 9:34pm on the night of the Gaze. (Per
Megastar)
Jupiter & it's moons: Jupiter sets at 2:38am. Moon activity: (1)
Io disappears into occultation at 00:44am, reappears after sun rise. (2)
The Great Red Spot (GRS) is not visible tonight. (Per the "Planets202"
program and S&T) .
(Note: if the gaze is postponed until Saturday night due to clouds, a nice Io sequence will be visible: Io begins transit (9:53pm), Io's shadow begins transit (11:09pm), Io exits transit (12:10am, and by the way, its shadow is about smack dab in the middle of Jupiter's disk at this time, just below the Great Red Spot!), & Io's shadow ends transit (1:25am).
You need only about a 6" reflector to see these transits! Begin to look for a Jovian moon in transit about 20 minutes before it leaves Jupiter's disk, or just after is has begun to cross in front of Jupiter's disk. Once the moon gets more towards the middle of Jupiter's disk, the tiny 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.
PLANETS:
Mercury: Regretfully, Mercury's transit
of the Sun on May 7th ends an hour before sunrise for us in WNC.
Venus: Rises about an hour before
the sun.
Mars: Quite small, about 11" diameter. Increases
from magnitude 0.0 to -0.6 this month. (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: About 35 degrees above the horizon at sunset
on the night of the star gaze, but only 18 degrees high at sunset by month's
end, so catch it early in the month and just after sunset. 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 -2.0)
& high (70 degrees) in the west at nightfall (contrast this with Mars being
only 40 degrees above the horizon during its close approach in August). Getting
dimmer, but still a good view. Catch it early in the night.
Asteroids: Vesta is mag 6.4 when May arrives,
but is at mag 7.0 the end of May. Unless you have sharp eyes and very dark skies,
you'll need binoculars to see it, even at the beginning of the month. 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)
NGC4565: A highly elongated, edge-on spiral galaxy in Coma Berenices.
Very nice, especially for a non-Messier object! The dust lane is visible in
8" scopes under dark skies. Mottling and knots are visible in larger scopes.
31 Million light years away, and about 125,000 light years in diameter. Catch
it early in the evening when it is high, or in March when it is high after midnight
and many offending community lights are turned off. Magnitude 9.6 (Location:
12hr 36m RA 25deg 59' Dec)
OMEGA CENTAURI: The most impressive Globular Cluster visible from Earth, too bad it is so far south. But to see it at all from this far north, May after dark is a good time to check it out if you have a clear view to the southern horizon. It crosses the meridian in mid-May at 10:00pm. Being 15,500 light years away, it is one of the nearest globulars, but is still 60% of the way to the galactic center (although 68 degrees to the west of galactic center, and a little south). There are about 1,000,000 stars in this 300 light-year-diameter cluster. Magnitude 3.5 (Location: 13h 27m R.A. -47 deg 29' Dec)
Delta Corvi (Double stars): a fairly bright, white primary paired with a dim pale blue secondary, 24.2" separation; Magnitudes 3.0 & 9.2. Their distance from Earth is 88 light years & true separation is 650 a.u. (16x that of our sun and Pluto). This pair is the upper-left star in Corvus. (Location: 12h 29.9m R.A. -16 deg 31' Dec)
STF 1669 CORVI (Double stars): a pair of equally bright yellow stars at 5.4" separation; Magnitudes 6.0 & 6.1. Their distance from Earth is 278 light years, & true separation is 426 a.u. (7x that of our sun and Pluto). (Location: 12hr 41m R.A. -13 deg 01' Dec).
28 CORVI (Double
stars) : a closer pair, yellow and white, at 2.2" separation; Magnitudes
6.5 & 8.6. Their distance from Earth is 81 light years, & true separation
is 53 a.u.. This makes their separation only 1.4x that of our sun and
Pluto (40 a.u.)! It is 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 80% of the way to the other star. Then sit there
and contemplate a while longer. (Location:12hr 30m R.A. -13
deg 24' Dec) See the orbital
plot at Richard Dibon-Smith web site.
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). Begin celebrating at sundown on April 30, as did the ancient
Celts. Their days began and ended with sunset.
Astronomy Day: May 10th.
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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
May): 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; high in the west
just after dark in May): 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-May, the Milky Way lies unseen all around you, along the horizon. Straight
overhead is the North Galactic Pole, in the constellation Coma Berenices. In
south-west 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 in early
morning hours in May): GLOBULAR CLUSTERS (blueow 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 May stargaze is Friday, May 2, 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.)
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Archived Monthly Sky 2002: Feb Mar
Apr May June
July Oct Nov
Dec
Archived Monthly Sky 2003: Mar Apr
