During this period the moon reaches its new phase on Tuesday September 23rd. At this time the moon is located near the sun and is not visible at night. This weekend the waning crescent moon will rise just before the start of morning twilight and will be too thin to bother meteor observers. 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 10 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 20/21. 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 01:12 (018) +05. This position lies in southeastern Pisces, 3 degrees south of the fourth magnitude star Epsilon Piscium. 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 September Epsilon Perseids (SPE) are active from a radiant located at 04:04 (061) +40. This position lies in southern Perseus, just east of the 3rd magnitude star Epsilon Persei. The radiant is best placed near 0500 LDT, when it lies highest above the horizon. Rates seen from the northern hemisphere should be near 1 per hour during the morning hours. With an entry velocity of 65 km/sec., most activity from this radiant would be swift. This activity is visible from the tropical regions of the southern hemisphere, but further south the radiant becomes too low in the sky to produce much activity.
The Orionids (ORI) are active from a radiant at 05:08 (077) +07, which places it in western Orion, 3 degrees west 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 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. Rates this week 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 Beta Aurigids (BAU) are active on only 5 nights centered on September 23rd. 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 be near 1 as seen from the northern hemisphere. Due to the low elevation as seen from the southern hemisphere, hourly rates would be less than 1 as seen from south of the equator. With an entry velocity of 69 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 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||01:12 (018) +05||29||02:00||2 – 2||II|
|September Epsilon Perseids (SPE)||Sep 09||04:04 (061) +40||65||05:00||1 – <1||II|
|Orionids (ORI)||Oct 22||05:08 (077) +07||67||06:00||2 – 2||I|
|Delta Aurigids (DAU)||Sep 27||05:08 (077) +57||61||06:00||<1 – <1||IV|
|Beta Aurigids (BAU)||Sep 23||05:52 (088) +48||69||07:00||1 – <1||IV|