[Prev][Next][Index][Thread]
(meteorobs) Meteor Activity Outlook for December 22-28, 2000
The moon is new on Christmas Day and will treat many new telescope
owners with a partial solar eclipse over much of North America. Never
look at the sun through your telescope, even during this eclipse. It is
a better and much safer idea to project the sun's image on to a clean
white sheet of paper. As the sun sets the entire night will be free of
moonlight allowing good conditions for meteor observing. The Ursid
shower is peaking tonight so make that the top observing priority of the
week. The positions listed below are exact for Saturday night/Sunday
morning December 23/24. The positions do not change greatly day to
day so these positions may be used during this entire period.
The Antihelion radiant is now located at 07:08 (107) +22. This area of
the sky is located in central Gemini 2 degrees west of the second
magnitude star Delta Geminorum. Any slow meteor from this area is a good
candidate for this shower. This area of the sky is best placed near 0100
local time when it lies on the meridian. At this time expect to see
perhaps 2 to 3 meteors per hour from this source.
The Northern Apex is now located at 12:08 (182) +14. This position lies
on the Virgo/Coma Berenices border some 5 degrees southeast of the
bright star Denebola (Beta Leonis). Since this radiant is diffuse
any meteors from eastern Leo, western Virgo, or Coma Berenices would be
a good candidate. As seen from the Northern Hemisphere this source
should still be active producing 3-4 meteors per hour near dawn.
Observers in the Southern Hemisphere should see similar rates. These
meteors should be reported as "COM" by observers reporting to the IMO.
The Southern Apex source lies exactly 30 degrees south of its northern
counterpart at 12:08 (182) -16. This position lies in northwestern
Corvus near the star Gamma Corvi. Like the northern apex these
meteors are best seen toward dawn when the radiant lies highest above
the horizon in a dark sky. Any meteor from Corvus or eastern Crater
could possibly be a good candidate from this source. As seen from the
Northern Hemisphere this source should produce 2-3 meteors per hour near
dawn. Rates seen from the Southern Hemisphere should be similar.
The Ursids are expected to peak tonight (Dec. 21/22) near 07:30
Universal Time. Northern USA and Canada are favored for this event as
the radiant will lie high in their skies. The radiant is located at
14:28 (217) +76, which is close to the second magnitude star Kochab,
located in the bowl of the Little Dipper. Due to this high northerly
location this display is not visible from the Southern Hemisphere.
Observers should watch for any enhanced activity between the hours of
0600 and 1000 UT which corresponds to 1am to 5am EST and 10pm to 2am
PST. I would not expect a dramatic increase occurring near 0730 UT.
Rather it most likely will be consistent good activity during these
hours with slight outbursts. The chances of seeing an Ursid fireball
would probably be best near 0730 UT. Actual visual rates are difficult
to predict. ZHR's could be as high as 100 or better. Even at these high
rates the actual visual rate is much lower with perhaps 50 or so per
hour being seen in Alaska and Canada, 40/hr from Northern USA, and
perhaps 30/hour from Southern USA. These estimates are for rural sites
away from city lights. Urban observers will see much less activity. Any
aurora activity would also tend to reduce the number of meteors seen.
The Ursid meteors are of medium velocity. This means that they will be
of average speed if seen far from the radiant and high in the sky. If
seen low in the sky or close to the radiant they will appear to travel
more slowly. Since the Ursids possess a average velocity persistent
trains are uncommon. Ursid meteors can be seen in any portion of the sky
but I would suggest facing toward the north to see the most Ursid
activity. It is suggested that you have the radiant within your field of
view to help you associate Ursids from other meteors. You need not stare
directly at the radiant but just be sure that you can easily see the
bowl of the Little Dipper. Good luck with your weather and be sure to
protect yourself from the cold temperatures.
The Sporadic rates for the Northern Hemisphere should still be strong.
One would expect to see perhaps 7-9 random meteors per hour during the
last hours before dawn from rural observing sites. During the evening
hours perhaps 3-4 random meteors can be seen per hour. Rates seen from
the Southern Hemisphere are on the upswing and nearly match those rates
seen from the north.
Clear Skies!
Robert Lunsford
AMS Visual Program Coordinator
To UNSUBSCRIBE from the 'meteorobs' email list, use the Web form at:
http://www.tiacdot net/users/lewkaren/meteorobs/subscribe.html