During this period the moon reaches its last quarter phase on Saturday October 26. This weekend the half-illuminated moon will rise near midnight and will remain in the sky the remainder of the morning. Successful meteor observations can be obtained if one faces away from the moon. Toward the end of this period the moon will not be much of a factor at all as it will be very slender and will rise just before dawn. The estimated total hourly meteor rates for evening observers this week is near 4 for observers located in the northern hemisphere and 3 for those viewing south of the equator. For morning observers the estimated total hourly rates should be near 20 as seen from mid-northern latitudes and near 15 for observers viewing from tropical southern latitudes. Rates during the morning hours are reduced by moonlight during this period. 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. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brightest meteors will be visible from such locations.
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 October 26/27. 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 sources of meteoric activity are expected to be active this week:
The first activity from the Andromedids (AND) will be seen this week. This is a famous shower that produced some brilliant displays during the 19th century. Since then the main orbit of the particles from comet 3D/Biela have moved away from the Earth. Still, remnants may be seen from October 26 through November 20 with maximum activity occurring on November 8. The radiant is currently located at 01:20 (020) +22, which lies in eastern Pisces, 10 degrees west of the 2nd magnitude star Hamal (Alpha Arietis). Rates would most likely be less than 1 per hour no matter your location. With an entry velocity of 19 km/sec., the average Andromedid meteor would be of slow velocity.
The Southern Taurids (STA) are currently active from a radiant located at 03:04 (046) +12. This position lies in southeastern Aries, 8 degrees north of the 3rd magnitude star known Menkar (Alpha Ceti). These meteors may be seen all night long but the radiant is best placed near 0200 local daylight time (LDT) when it lies on the meridian and is located highest in the sky. Rates at this time should be near 2 per hour regardless of your location. With an entry velocity of 29 km/sec., the average Southern Taurid meteor would be of slow velocity.
The Northern Taurids (NTA) are now active from a large radiant centered at 03:08 (047) +20, which lies in eastern Aries, close to the position occupied by the fourth magnitude star known as Delta Arietis. The radiant is best placed near 0200 local daylight time (LDT), when it lies highest above the horizon. Meteors from the Northern Taurids strike the atmosphere at 29km/sec., which would produce meteors of slow velocity. Expected rates would be near two per hour, no matter your location.
The Orionids (ORI) are active from a radiant at 06:36 (099) +16, which places it in southwestern Gemini, close to the spot occupied by the 2nd magnitude star known as Alhena (Gamma Geminorum). This area of the sky is best placed in the sky near 0500 LDT, when it lies highest above the horizon. Rates this week should still be near 5 per hour no matter your location. With an entry velocity of 67 km/sec., most activity from this radiant would be of swift speed.
Recent analysis of the IMO video database has shown that the Epsilon Geminids (EGE) are active as early as September 22. The current radiant position would be located near 07:08 (107) +27, which places it in central Gemini, directly between the 1st magnitude star Pollux (Beta Geminorum) and 3rd magnitude Mebsuta (Epsilon Geminorum). This area of the sky is best placed in the sky during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates should be near 2 per hour as seen from the northern hemisphere and near 1 when view south of the equator. With an entry velocity of 70 km/sec., most activity from this radiant would be of swift speed.
The last of the Leonis Minorids (LMI) will be seen this week. The radiant is currently located at 10:56 (164) +36. This position lies in northeastern Leo Minor near the faint star known as 46 Leonis Minoris. This position is also close to the mid-way point between the brighter stars Nu and Upsilon Ursae Majoris. This area of the sky is best placed in the sky during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates should be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from south of the equator. With an entry velocity of 68 km/sec., most activity from this radiant would be of swift speed.
The Lambda Ursae Majorids (LUM) are a recent discovery by Zeljko Andreic. This weak shower is active from October 24 through November 1st with maximum activity occurring on the 27th. The radiant currently located at 10:20 (155) +50. This position lies in a sparse area of central Ursa Major, between the 2nd magnitude star Merak (Beta Ursae Majoris) and 3rd magnitude Tania Borealis (Lambda Ursa Majoris). This area of the sky is best placed in the sky during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates should be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from south of the equator. With an entry velocity of 62 km/sec., most activity from this radiant would be of swift speed.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 8 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 3 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 5 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Moonlight reduces the number of meteors seen during the morning hours during this period.
The table below presents a list of radiants that are expected to be active this week. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.
|SHOWER||DATE OF MAXIMUM ACTIVITY||CELESTIAL POSITION||ENTRY VELOCITY||CULMINATION||HOURLY RATE||CLASS|
|RA (RA in Deg.) DEC||Km/Sec||Local Daylight Time||North-South|
|Andromedids (AND)||Nov 08||01:20 (020) +22||19||00:00||<1 – <1||III|
|Southern Taurids (STA)||Oct 10||03:04 (046) +12||29||02:00||2 – 2||II|
|Northern Taurids (NTA)||Nov 11||03:08 (047) +20||29||02:00||2 – 2||II|
|Orionids (ORI)||Oct 22||06:36 (099) +16||67||05:00||5 – 5||I|
|Epsilon Geminids (EGE)||Oct 22||07:08 (107) +27||70||06:00||2 – 1||II|
|Lambda Ursae Majorids (LUM)||Oct 27||10:20 (155) +50||62||09:00||1 – <1||IV|
|Leonis Minorids (LMI)||Oct 22||10:28 (157) +36||62||09:00||1 – <1||II|