(meteorobs) Meteor Activity Outlook for April 4-10, 2008

[Robert Lunsford]

Meteor activity picks up a bit during April as two major showers are active
during the month. The first of these, the Lyrids, are active from the 16th
through the 25th, with a pronounced maximum on the 22nd. Unfortunately this
date coincides with a full moon this year so activity will be reduced. The
Eta Aquarids start appearing near the 20th and reach maximum activity during
the first week in May. Sporadic rates are low but steady as seen from the
mid-northern hemisphere (45 N). Sporadic rates seen from the mid-southern
hemisphere (45 S) rise this month toward a maximum in July.

During this period the moon reaches its new phase on Sunday April 6th. At
this time the moon will be located near the sun and will not be visible at
night. Next week the waxing crescent moon enters the evening sky but will
not interfere with observations. As seen from the mid-northern hemisphere
(45 N) the estimated total hourly rates during the evening observers would
be two. For morning observers the estimated total hourly rates should be
near eleven. For those located in the mid-southern hemisphere (45 S) morning
rates would be near sixteen and evening rates near three. These rates assume
that you are watching from rural areas away from all sources of light
pollution. The actual rates will also depend on factors such as personal
light and motion perception, local weather conditions, alertness and
experience in watching meteor activity.

The radiant positions and rates listed below are exact for Saturday
night/Sunday morning April 5/6. These positions do not change greatly day to
day so the listed coordinates may be used during this entire period. Most
star atlases (available at science stores and planetariums) will provide
maps with grid lines of the celestial coordinates so that you may find out
exactly where these positions are located in the sky. A planisphere or
computer planetarium program is also useful in showing the sky at any time
of night on any date of the year. Activity from each radiant is best seen
when it is positioned highest in the sky, either due north or south along
the meridian, depending on your latitude. It must be remembered that meteor
activity is rarely seen at the radiant position. Rather they shoot outwards
from the radiant so it is best to center your field of view so that the
radiant lies at the edge and not the center. Viewing there will allow you to
easily trace the path of each meteor back to the radiant (if it is a shower
member) or in another direction if it is a sporadic. Meteor activity is not
seen from radiants that are located below the horizon. The positions below
are listed in a west to east manner in order of right ascension (celestial
longitude). The positions listed first are located further west therefore
are accessible earlier in the night while those listed further down the list
rise later in the night.

The following showers are expected to be active this week:

The wide Antihelion (ANT) radiant is now centered at 13:56 (209) -11. This
area of the sky lies in southern Virgo, eight degrees east of the first
magnitude star Spica (Alpha Virginis). This radiant is best placed near 0200
LDT time when it lies on the meridian and is highest in the sky. Actually
any meteor from southern Virgo or western Libra could be a candidate for
this shower. Rates at this time should be near three per hour no matter your
location. With an entry velocity of 30 km/sec., the average Antihelion
meteor would be of medium-slow speed.

As seen from the mid-northern hemisphere (45N) the Sporadic rates are low,
but fairly steady. One would expect to see approximately eight random
meteors during the last hour before dawn from rural observing sites and two
per hour during the evening hours. As seen from the mid-southern hemisphere
(45S) morning rates would be near thirteen per hour as seen from rural
observing sites and three per hour during the evening hours.

The table below presents a condensed version of the expected activity this
week. Rates and positions are exact for Saturday night/Sunday morning.

Antihelion (ANT) - 13:56 (209) -11 30 02:00   Velocity - 30km/sec.
Northern Hemisphere - 3   Southern Hemisphere - 3

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2008

Clear Skies!
Robert Lunsford
American Meteor Society