During this period the moon will reach its first quarter phase on Sunday November 26th. At this time the half-illuminated moon will lie 90 degrees east of the sun and will set near 2300 (11pm) local standard time (LST). The moon will interfere with evening observing but will set before the more active morning hours arrive. Toward the end of this period the waxing gibbous moon will remain in the sky most of the night, obscuring all but the brighter meteors. The estimated total hourly meteor rates for evening observers this week is near 4 as seen from mid-northern latitudes (45N) and 3 as seen from tropical southern locations (25S). For morning observers the estimated total hourly rates should be near 18 as seen from mid-northern latitudes and 12 from the southern tropics. 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. Evening meteor rates are reduced during this period due to moonlight. 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 brighter 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 November 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 near 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 far 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.
These sources of meteoric activity are expected to be active this week.
The December phi Cassiopeiids (DPC) are now recognized as remnants of comet 3D/Biela that produced moderate showers in the 1700 and 1800’s prior to the Andromedid storms. These meteors are active from November 28 to December 10, with maximum activity occurring on December 4. The radiant is currently located at 00:40 (010) +55. This area of the sky is located in southern Cassiopeia, 2 degrees south of the 2nd magnitude star known as Schedar (alpha Cassiopeiae). Current rates would be less than 1 per hour no matter your location. Due to the high northern location of the radiant, these meteors would be difficult to observe from locations south of the southern tropics. These meteors are best seen near 20:00 (8:00pm) local standard time (LST) when it lies on the meridian and is located highest in the sky. With an entry velocity of 17 km/sec., the average December phi Cassiopeiid meteor would be of very slow velocity.
The Northern Taurids (NTA) are active from a large radiant located at 04:54 (074) +27. This area of the sky is located in northern Taurus, 6 degrees southwest of the 2nd magnitude star known as El Nath (beta Tauri). This position is close to the Southern Taurids so great care must be taken in separating these meteors. You must have the two radiants near the center of your field of view to properly differentiate these sources. Current rates would be 2 per hour as seen from the northern hemisphere and 1 per hour as seen from south of the equator. These meteors may be seen all night long but the radiant is best placed near midnight LST when it lies on the meridian and is located highest in the sky. With an entry velocity of 28 km/sec., the average Northern Taurid meteor would be of slow velocity.
The Southern Taurids (STA) are active from a large radiant centered near 05:02 (076) +20. This position lies in central Taurus, 6 degrees northeast of the orange 1st magnitude star known as Aldebaran (alpha Tauri). These meteors may be seen all night long but the radiant is best placed near midnight LST when it lies on the meridian and is located highest in the sky. Rates at this time should be near 1 per hour regardless of your location. With an entry velocity of 27 km/sec., the average Southern Taurid meteor would be of slow velocity.
The first of the Monocerotids (MON) should appear this week from a radiant located near 05:44 (086) +09. This area of the sky is located in northern Orion, 3 degrees northwest of the bright orange star known as Betelgeuse (alpha Orionis). This stream is active from November 28 through December 27, with maximum occurring on December 13. Current rates are expected to be less than 1 per hour no matter your location. These meteors are best seen near 0100 LST, when it lies highest above the horizon in a dark sky. With an entry velocity of 41 km/sec., the average Monocerotid meteor would be of medium velocity.
The November Orionids (NOO) are currently the most active radiant in the sky. The radiant is located at 05:52 (088) +16, which lies on the Taurus/Orion border, 8 degrees north of the 1st magnitude orange star known as Betelgeuse (alpha Orionis). This area of the sky is best placed in the sky near 0100 LST, when it lies highest above the horizon. This stream is active from November 7 through December 17, with maximum activity occurring on November 29. Rates should be near 3 per hour as seen from mid-northern latitudes and 2 as seen from sites south of the equator. With an entry velocity of 43 km/sec., most activity from this radiant would be of medium speed.
The theta Aurigids (THA) were discovered by Dr. Peter Brown using the Canadian Meteor Orbit Radar. This stream is active from November 17 through December 1, with maximum activity occurring on November 26. The radiant currently lies at 06:23 (096) +35, which places it in southeastern Auriga, 4 degrees southeast of the 3rd magnitude star known as theta Aurigae. This area of the sky is best placed in the sky near 0200 LST, when it lies highest above the horizon in a dark sky. Rates should be less than 1 per hour no matter your location. With an entry velocity of 33 km/sec., most activity from this radiant would be of medium-slow velocity. These meteors are expected to be faint and may be difficult to observe unless viewing conditions are near optimum.
The first of the sigma Hydrids (HYD) should appear this weekend from a radiant located at 07:44 (116) +05. This area of the sky is located in Canis Minor, just east of the brilliant zero magnitude star known as Procyon (alpha Canis Minoris). Since the maximum is not until December 6, rates are expected to be less than 1 per hour no matter your location. These meteors are best seen near 0300 LST, when it lies highest above the horizon in a dark sky. With an entry velocity of 61 km/sec., the average sigma Hydrid meteor would be of swift velocity.
The Leonids (LEO) are still active from a radiant located at 10:51 (163) +19. This area of the sky is located in central Leo, 5 degrees east of the 2nd magnitude star known as Algeiba (gamma Leonis). Rates are expected to be less than 1 per hour no matter your location. These meteors are best seen during the last hour before dawn when the radiant lies highest above the horizon in a dark sky. With an entry velocity of 70 km/sec., the average Leonid meteor would be of swift velocity.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 12 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 8 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. Evening rates are reduced during this period due to moonlight.
The list below offers the information from above in tabular form. 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 Standard Time||North-South|
|December phi Cassiopeiids (DPC)||Dec 04||00:40 (010) +55||17||20:00||<1 – <1||IV|
|Northern Taurids (NTA)||Nov 02||04:54 (074) +27||28||00:00||2 – 1||II|
|Southern Taurids (STA)||Oct 29-Nov 03||05:02 (076) +20||27||00:00||1 – 1||II|
|Monocerotids (MON)||Dec 13||05:44 (086) +09||41||01:00||<1 – <1||II|
|November Orionids (NOO)||Nov 29||05:52 (088) +16||43||01:00||3 – 2||II|
|theta Aurigids (THA)||Nov 26||06:23 (096) +35||33||02:00||<1 – <1||IV|
|sigma Hydrids (HYD)||Dec 06||07:44 (116) +05||61||03:00||<1 – <1||II|
|Leonids (LEO)||Nov 17||10:51 (163) +19||70||06:00||<1 – <1||I|