During this period the moon reaches its first quarter phase on Wednesday October 1st. At this time the moon is located 90 degrees east of the sun and sets near midnight local daylight time (LDT). This weekend the waxing crescent moon will set during the mid-evening hours and will not interfere with viewing during the active morning hours. The estimated total hourly meteor rates for evening observers this week is near 4 as seen from the northern hemisphere and 3 as seen from southern tropical latitudes. For morning observers the estimated total hourly rates should be near 16 for observers located in mid-northern latitudes and 12 for south tropical observers. 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 September 27/28. 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.
These sources of meteoric activity are expected to be active this week:
The Southern Taurids (STA) are currently active from a radiant located at 01:32 (023) +07. This position lies in southeastern Pisces, 3 degrees southwest of the faint star known as Omicron Piscium. These meteors may be seen all night long but the radiant is best placed near 0200 LDT when it lies on the meridian and is located highest in the sky. Rates at this time should be near 3 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 Delta Aurigids (DAU) are active from September 23-29, with a peak on the 27th. On the night of maximum activity the radiant is located at 05:08 (077) +57. This area of the sky lies in southern Camelopardalis, 10 degrees north of the zero magnitude star known as Capella (Alpha Aurigae). This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Even at maximum, rates would be less than 1 per hour no matter your location. With an entry velocity of 61 km/sec., most activity from this radiant would be of swift speed.
The Orionids (ORI) are active from a radiant at 05:24 (081) +10, which places it in northwestern Orion, 4 degrees north of the 2nd magnitude star known as Bellatrix (Gamma Orionis). This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Rates this week would be near 2 per hour no matter your location. With an entry velocity of 67 km/sec., most activity from this radiant would be of swift speed.
The last of the Beta Aurigids (BAU) are active this weekend. The position of this radiant lies at 05:52 (088) +48, which lies in northern Auriga, 3 degrees northwest of the 2nd magnitude star known as Menkalinan (Beta Aurigae). This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Hourly rates would most likely be less than 1 no matter your location. With an entry velocity of 69 km/sec., most activity from this radiant would be of swift speed.
The September-October Lyncids (SOL) are only active on 4 nights from September 27-30. Peak activity occurs on the 29th when the radiant lies at 07:26 (111) +47. This position lies in a remote area of Lynx, 15 degrees north of the 2nd magnitude star known as Castor (Alpha Geminorum). This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Hourly rates would most likely be near 1 as seen from the northern hemisphere and less than 1 as seen south of the equator. With an entry velocity of 65 km/sec., most activity from this radiant would be of swift speed.
The Daytime Sextantids (DSX) are mainly thought of as a daylight shower, only visible by radio and radar means. Actually the radiant lies slightly more than 30 degrees west of the sun and members of this shower should be visible during the last hour before the start of nautical twilight, when the sun lies 12 degrees below the horizon. Shower members would shoot upwards from the eastern horizon as dawn is breaking. The International Meteor Organization is asking observers to try and view activity from this source between September 25 and October 6. Maximum activity is thought to occur on September 29th. The radiant should be considered to lie at 10:16 (154) -01. This position lies in central Sextans, 3 degrees east of the 4th magnitude star known as Alpha Sextantis. This area also lies a dozen degrees south of the bright star Regulus (Alpha Leonis). This is one of the stronger “daytime” showers so the visual observer may see several meteors from this source each morning during the period mentioned above. With an entry velocity of 33 km/sec., most activity from this radiant would be of medium-slow velocity. These meteors can be seen equally well from both hemispheres.
As seen from the mid-northern hemisphere (45N) one would expect to see approximately 10 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 6 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.
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 Daylight Time||North-South|
|Southern Taurids (STA)||Oct 10||01:32 (023) +07||29||02:00||3 – 3||II|
|Delta Aurigids (DAU)||Sep 27||05:08 (077) +57||61||06:00||<1 – <1||IV|
|Orionids (ORI)||Oct 22||05:24 (081) +10||67||06:00||2 – 2||I|
|Beta Aurigids (BAU)||Sep 23||05:52 (088) +48||69||07:00||<1 – <1||IV|
|Sep-Oct Lyncids (SOL)||Sep 29||07:26 (111) +47||65||08:00||1 – <1||IV|
|Daytime Sextantids (DSX)||Sep 29||10:16 (154) -01||33||11:00||2 – 2||IV|