Meteor Activity Outlook for 14-20 August 2021

Wojciech Maziarz captured this fireball on the morning of 1 August 2021 at 2:35am EDT (6:51UT) from South Gibson, PA, USA. For more information on this fireball, visit: https://fireball.amsmeteors.org/members/imo_view/event/2021/4202 ©Wojciech Maziarz

During this period, the moon reaches its first quarter phase on Sunday August 15th. At that time the moon lies 90 degrees east of the sun and sets near 23:00 local summer time (on Aug. 14). As the week progresses the waxing gibbous moon sets later and later, diminishing the available time of dark sky with each passing night. 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 27 as seen from mid-northern latitudes (45N) and 12 as seen from tropical southern locations (25S). 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 rates are reduced this week due to interfering 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 August 14/15. 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. I have also included charts of the sky that display the radiant positions for evening, midnight, and morning. The center of each chart is the sky directly overhead at the appropriate hour. These charts are oriented for facing south but can be used for any direction by rotating the charts to the desired direction. 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 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.

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The kappa Cygnids (KCG) are active from August 3-25, with maximum occurring on the 17^th. The radiant shifts rapidly towards the northeast with each passing night. The radiant is currently located at 19:00 (285) +59, which places it in southeastern Draco, 2 degrees east of the faint star known as omicron Draconis. This radiant is also best placed near 2300 local summer time (LST) when it lies on the meridian and is located highest in the sky. With a high northern declination, these meteors are difficult to view from the southern hemisphere. Expected hourly rates this week are less than 1 no matter your location. With an entry velocity of 25 km/sec., the average meteor from this source would be of slow velocity.

The center of the large Anthelion (ANT) radiant is currently located at 22:20 (335) -8. This position lies in central Aquarius, very close to the position of the 4th magnitude star known as Ancha (theta Aquarii). This position is also 5 degrees northeast of the brilliant planet Jupiter. Due to the large size of this radiant, Anthelion activity may also appear from eastern Capricornus as well as Aquarius. This radiant is best placed near 0200 LST, when it lies on the meridian and is located highest in the sky. Rates at this time should be near 2 per hour no matter your location. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The Southern delta Aquariids (SDA) are active from a radiant located at 23:28 (352) -12. This area of the sky is located in central Aquarius, 7 degrees northeast of the 3rd magnitude star known as Skat (delta Aquarii). This radiant is best placed near 0300 LST, when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be less than 1 as seen from the Northern Hemisphere and near 1 as seen from south of the equator, where the radiant lies higher in the sky. With an entry velocity of 41 km/sec., the average meteor from this source would be of medium velocity.

The Perseids (PER) are still active from a radiant located at 03:24 (051) +58. This position lies in southwestern Camelopardalis, 8 degrees north of the 2^nd magnitude star known as Mirfak (alpha Persei). This area of the sky is best placed for viewing during the last dark hour before dawn when it lies highest in the sky. Current hourly rates are expected to be near 10 as seen from the Northern Hemisphere and near 1 as seen from south of the equator. These rates will decrease with each passing night as the week progresses. With an entry velocity of 59 km/sec., the average meteor from this source would be of swift velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 14 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 4 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 9 per hour as seen from rural observing sites and 3 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.