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Re: (meteorobs) Meteor Activity for the Week of December 24-31, 1999

     At the risk of stepping out of my league, I would like to add that
observing before midnight does have one advantage over later hours...the
meteors that ARE seen are on average brighter than post-midnight.  Chances
of seeing fireballs diminish a bit as one goes from 6 pm to 12 am and
beyond.   So while one may see fewer meteors, the ones seen tend to be more
of a treat!
Kim Youmans

Robert Lunsford wrote:

> The moon has just passed its full phase and is now waning toward last
> quarter. This will free up the early evening hours for observing without
> lunar interference. Typically at this time of night one would see an
> average of 5 sporadic (random) meteors per hour from dark rural
> observing sites. Once the moon reaches last quarter on Wednesday,
> December 29, the entire evening will be free of moonlight. At this time
> it is often asked if it is better to watch before midnight in dark skies
> or to endure lunar interference during the morning hours. On most
> occasions observers would see more activity during the morning hours
> despite the presence of moonlight. Meteor rates are stronger after
> midnight and the last quarter moon is much less intense than it is
> when near full. This allows rural observers to achieve limiting
> magnitudes of 6.0 when facing areas of the sky away from the moon.
> Sporadic rates would be near 10 per hour under such conditions so
> meaningful data can be obtained despite the presence of moonlight.
>
> For observers limited to watching during the early evening hours, the
> only known radiant above the horizon at this time would be the Chi
> Orionids. During this week this radiant is located in south-central
> Gemini near the position 6:45 +20. The radiant is just below the horizon
> at dusk rising higher into the eastern sky as evening progresses. It
> reaches the meridian (due south) between midnight and 0100 and is best
> situated for viewing at this time. This shower produces meteors of
> medium-slow speed with typically 1-2 shower members per hour this time
> of year.
>
> The Coma Berenicid activity continues this week with the radiant lying
> in western Coma Berenices near the position 12:12 +22. The radiant rises
> near midnight therefore no activity can be seen from this shower during
> the evening hours. The best rates from this shower will occur just
> before dawn when the radiant lies high in the south. The Coma Berenicids
> are swift meteors with many persistent trains. The moon is located near
> the radiant early next week so be sure to face away from this area,
> perhaps toward the north or the southwest to avoid direct moonlight and
> the loss of night vision.
>
> During my Geminid observations I happen to notice several swift meteors
> each morning coming from an area near the Leo-Virgo border. These
> meteors are related to the Apex radiant which lies 90 degrees west of
> the sun and produces 1-2 meteors per hour on average. This radiant is
> now located in western Virgo near the position 12:30 -3. This is close
> to the famous 3rd magnitude double star Porimma or Gamma Virginis. This
> radiant also rises near midnight and is best seen just before dawn.
> Enhanced Coma Berenicid rates could be due to inclusion of these apex
> meteors since the velocities are similar and the radiants are fairly
> close in the sky. Once the moon is out of the picture it is suggested to
> face a bit more toward these radiants to aid in shower association.
>
> Finally, there have been scattered reports of activity from the
> constellation of Lynx during this period. This faint but large
> constellation is located in the area between the Big Dipper and Gemini.
> Any possible activity from this area would possess medium velocities.
> Any confirmation of such activity or lack of activity would be important
> in assisting us analyze activity for this particular time period.
>
> Merry Christmas Everyone!
>
> Bob Lunsford
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