(meteorobs) Meteor Activity Outlook for December 25-31, 2010

[Richard Kramer]

Robert,

Something must be different about your email 
client. This week's activity outlook came as a 
typographical monolith (see  below), a single 
massive "paragraph" of words, hard to read..

Regards and best wishing for the coming year,
Richard


At 01:28 PM 12/27/2010, you wrote:
>During this period the moon reaches its last 
>quarter phase on Tuesday December 28th. At this 
>time the moon lies ninety degrees west of the 
>sun and rises near midnight local standard time 
>(LST) for those located in the mid-northern 
>latitudes. With the moon waning and rising later 
>each morning, this opens up another opportunity 
>to view meteor activity under improving 
>conditions. The estimated total hourly rates for 
>evening observers this week is near four from 
>the northern hemisphere and three for observers 
>south of the equator. For morning observers the 
>estimated total hourly rates should be near 
>fifteen from the northern hemisphere and twelve 
>as seen from the southern hemisphere. 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. Morning rates are 
>reduced this week due to moonlight. The radiant 
>(the area of the sky where meteors appear to 
>shoot from) positions and rates listed below are 
>exact for Saturday night/Sunday morning December 
>25/26. 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: Now that the activity from 
>particles produced by comet 2P/Encke has ceased 
>encountering the Earth, the Taurid showers for 
>2010 are over and we resume reporting activity 
>from the Antihelion (ANT) radiant. This is not a 
>true radiant but rather activity caused by the 
>Earth’s motion through space. As the Earth 
>revolves around the sun it encounters particles 
>orbiting in a prograde motion that are 
>approaching their perihelion point. They all 
>appear to be radiating from an area near the 
>opposition point of the sun, hence the name 
>Antihelion. These were once recorded as separate 
>showers throughout the year but it is now 
>suggested to bin them into their category 
>separate from true showers and sporadics. This 
>radiant is a very large oval some thirty degrees 
>wide by fifteen degrees high. Activity from this 
>radiant can appear from more than one 
>constellation. The position listed here is for 
>the center of the radiant which is currently 
>located at 07:08 (107) +22. This position lies 
>in central Gemini, two degrees west of the 
>fourth magnitude star Delta Geminorum. Since the 
>radiant is so large, Antihelion activity may 
>also appear from eastern Taurus, northeastern 
>Orion, western Cancer, or southern Auriga. This 
>radiant is best placed near midnight LST when it 
>lies on the meridian and is highest in the sky. 
>Rates at this time should be near three per hour 
>as seen from the northern hemisphere and two per 
>hour from south of the equator. With an entry 
>velocity of 30 km/sec., the average Antihelion 
>meteor would be of slow velocity. Activity from 
>the Alpha Hydrids (AHY) begin to appear on the 
>morning of December 30th. This shower reaches 
>maximum activity on the 31st from a radiant 
>located at 08:24 (126) -08. This position lies 
>in extreme western Hydra, fifteen degrees west 
>of the second magnitude star Alphard (Alpha 
>Hydrae). These meteors are best seen near 0200 
>LST when the radiant lies highest above the 
>horizon. Hourly rates from this shower will be 
>less than one per hour away from the night of 
>maximum activity. Rates as high as two per hour 
>may be seen on the morning of the 30th, no 
>matter your location. At 45 km/sec. the Alpha 
>Hydrids produce meteors of medium velocity. The 
>December Leonis Minorids (DLM) are active from a 
>radiant located at 11:06 (167) +27. This 
>position lies in a blank area of the sky where 
>the borders of Leo Minor, Leo, and Ursa Major 
>meet. The nearest bright stars are Nu and Xi 
>Ursae Majoris which lie five degrees to the 
>northeast. These meteors are best seen near 0500 
>LST when the radiant lies highest above the 
>horizon. This shower peaked on December 20th so 
>current rates would be near one per hour as seen 
>from the northern hemisphere and less than one 
>per hour as seen from south of the equator. At 
>64 km/sec. the December Leonis Minorids produce 
>mostly swift meteors. As seen from the 
>mid-northern hemisphere (45N) one would expect 
>to see approximately ten Sporadic meteors per 
>hour during the last hour before dawn as seen 
>from rural observing sites. Evening rates would 
>be near three per hour. As seen from the 
>mid-southern hemisphere (45S), morning rates 
>would be near eight per hour as seen from rural 
>observing sites and two per hour during the 
>evening hours. Locations between these two 
>extremes would see activity between the listed 
>figures. Morning rates are reduced by moonlight 
>during this period. The list below presents a 
>condensed version of the expected activity this 
>week. Rates and positions are exact for Saturday 
>night/Sunday morning. Antihelions (ANT) - 07:08 
>(107) +22   Velocity - 30km/sec. Northern 
>Hemisphere - 3 per hr. Southern Hemisphere - 2 
>per hr Alpha Hydrids (AHY) - 08:24 (126) 
>-08  Velocity - 45 km/sec. Northern Hemisphere - 
>1 per hr. Southern Hemisphere - 1 per hr. 
>December Leonis Minorids (DLM) - 11:06 (167) +27 
>Velocity - 71km/sec. Northern Hemisphere - 1 per 
>hr. Southern Hemisphere - <1 per 
>hr 
>Clear Skies! Robert Lunsford American Meteor 
>Society 
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