* Astronomy

Blobrana · L

RE: April 2012

Blobrana · L

Tonight's Sky: April 2012

Blobrana · L

Asteroid (42) Isis is at Opposition on the 6th April 2012

Asteroid (37) Fides is at Opposition on the 7th April 2012

Asteroid (116) Sirona is at Opposition on the 8th April 2012

Asteroid (423) Diotima is at Opposition on the 29th April 2012

Blobrana · L

Astronomers expect the annual Lyrid meteor shower to reach its peak between 10 p.m. and midnight on Saturday, April 21, although it's likely that you can spot some Lyrids until dawn Sunday, April 22.
The Lyrids appear to radiate out of the constellation Lyra, in the northeastern part of the sky in the late evening in April. However, they may appear in any part of the sky.
The bad news is that Lyrids are seldom numerous. From a dark site, you may see 10 or 20 meteors an hour. Every so often, though, the shower erupts with bursts of up to 100 meteors an hour.
The good news is that the moon won't interfere with meteor watching, and, since the peak takes place on a Saturday night, kids can stay up late and check it out.
Read more

Blobrana · L

The derivation of the name (Latin Aprilis) is uncertain. The traditional etymology is from the Latin aperire, "to open," in allusion to its being the season when trees and flowers begin to "open," which is supported by comparison with the modern Greek use of "opening" for spring. Since some of the Roman months were named in honor of divinities, and as April was sacred to Venus, the Festum Veneris et Fortunae Virilis being held on the first day, it has been suggested that Aprilis was originally her month Aphrilis, from her Greek name Aphrodite (Aphros), or from the Etruscan name Apru. Jacob Grimm suggests the name of a hypothetical god or hero, Aper or Aprus.
Read more

Blobrana · L

Highlights

From a very dark location at that time, look for the Zodiacal Light, a huge soft glowing column of light in the western horizon. It is the light of the Sun reflected off dust particles in the inner solar system. Its axis closely coincides with the ecliptic.

The Lyrids
On April 21 (16-25) The Lyrid meteor shower reaches maximum around midnight tonight, although the peak is broad enough that the number of meteors should be consistent until morning twilight. Although the Lyrids are considered a major shower, they produce a meteor only every 3 to 5 minutes, on average. The near New Moon won't compete with the shower. The Lyrids are named after the constellation of Lyra from which they seem to radiate. deep-sky objects to have been recorded by the ancients, being mentioned by Aristotle around 325 BC.

The Summer Triangle
The morning sky, before dawn, now provides a preview of summer evenings. The Summer Triangle -- Vega, Deneb, and Altair -- holds the central position, high in the south. The scorpion sits low to the south and slightly west. Directly to the arachnid's east is Sagittarius, the Archer, and between the two lies the direction toward the Milky Way galaxy's center. The ribbon of soft light that delineates our galaxy flows up from the south, through the Triangle, and then cascades toward the northern horizon.

Blobrana · L

Meteor Showers

This month sees the arrival of the Lyrids and the Virginids. Neither shower is very intense, but they do provide you with examples of shooting stars with different speeds: the fast Lyrids compared to the slower Virginids.
The peak of the April Lyrids (from the constellation of Lyra, the Harp) is on the 22nd, 5:00 UT, when you could see a maximum of about 15 meteors an hour.
The Virginids are active until the 18th, peaking on the 11th with 10 meteors an hour.
Watch out for sporadic meteors. Their rates for the Northern Hemisphere are now reaching a plateau. Expect around 12 random meteors per hour during the morning hours

Shower	Activity Period	Maximum	Radiant		Velocity	ZHR
		Date	R.A.	Dec.	km/s
Zeta Cygnids	Mar 27 to April 13	Apr. 6	295°	37	44	2
Gamma Virginids	Jan 25 to April 18	Apr. 11	195°	-04°	33	4.6
Lyrids	April 19 - 25	Apr22 23 UT	271°	+34°	49	15
Pi Puppids	April 18-25	Apr23	110°	-45°		18

Blobrana · L

Mercury: at magnitude 2.0, starts the month in the constellation of Pisces. Mercury is at aphelion (distance to sun: 0.4667 AU) at 5:00 UT, 15th April. Mercury is at Greatest Elongation (27.5° West, in the mornings, brightness: 0.4 mag) on the 18th April. Mercury is at Dichotomy (Half phase) on the 21st April.
(On April 1st, )

Venus: is at magnitude -4.4. Venus reaches magnitude -4.52 at the end of the month. The planet is in constellation Taurus at the start of the month. It is best seen from 6.4h -23.9h. Venus is near to the Pleiades star cluster on the 3rd April, 2012.
(On April 1st, RA= 3h37m57s Dec=+23°00.7' (J2000) Distance=0.671AU Elongation= 46° Phase k=48% Diameter=24.9")

Earth: -

The Moon: Full Moon (diameter: 33.278', declination: -10.39°) at 19:18.7 UT, 6th April. Lunar perigee (distance 358306.0 km, apparent diameter: 33'57.4") at 17:05.6 UT, 7th April, 2012. Last Quarter Moon at 10:49.6 UT, 13th April.
New Moon (diameter: 29.442', declination: 14.74°) at 7:18.4 UT, 21st April. Lunar Apogee (distance 406429.1 km, apparent diameter: 29'52.3") at 14:02.9 UT, 22nd April. First Quarter Moon at 9:57.5 UT, 29th April, 2012.

Mars: at magnitude -0.7 starts the month in the constellation Leo. Martian summer began on northern hemisphere on the 30th March, 2012. The Moon is close to Mars on the 3rd April, 2012. Mars is stationary on the 14th April.
(On April 1st, RA=10h30m15s Dec=+12°55.2' (J2000) Distance=0.749AU Phase k=96% Diameter=12.5")

Jupiter: is in the constellation Aries. At magnitude -2.1, the planet is best seen from 19.1h -21.8h. The Moon is close to Jupiter on the 22nd April, 2012.
Transit times of the Great Red Spot are posted in a seprate thread.
(On April 1st, RA= 2h44m33s Dec=+15°00.3' (J2000) Distance=5.820AU Diameter=33.8")

Saturn: at magnitude 0.3 sits in the constellation Virgo. The planet is best seen from 20.0h - 5.3h. Saturn is at opposition (distance to earth: 8.720 AU, brightness: 0.2 mag, diameter: 18.98") on the 15th April.
(On April 1st, RA=13h44m26s Dec= -7°50.7' (J2000) Distance=8.749AU Diameter=18.9")

Uranus: is in the constellation Pisces. Uranus at magnitude 5.9, has a bluish-green hue and appears 3.3 arcseconds wide. Uranus was in conjunction on the 24th March, 2012. The planet is unobservable this month. Mercury is close to Uranus (2.0° separated from center of Uranus) on the 22nd April, 2012.
(On March 1st, RA= 0h12m19s Dec= +0°34.7' (J2000) Distance=20.991AU Diameter=3.3")

Neptune: is at magnitude 7.9 in the constellation Aquarius. The planet is best seen the morning sky. Neptune was in conjunction on the 19th February, 2012.
(On December 1st, RA=22h01m53s Dec=-12°38.9' (J2000) Distance=30.174AU Elongation= 79° Diameter=2.2")

Pluto: is in the constellation Sagittarius (mag 14.1). Normally, a finder chart is necessary to help in identifying the 0.1" diameter dwarf planet. The dwarf planet is best seen from 20.8h - 3.7h. Pluto is stationary on the 10th April.
(On April 1st, RA=18h39m37s Dec=-19°13.5' (J2000) Distance=32.138AU Diameter=0.1")

The Sun enters the zodiac sign of Taurus at 16:12 UT on the 19th April, 2012.