Meteor activity kicks into high gear in August as seen from the Northern Hemisphere. The main reason for all this activity is the Perseid shower that peaks on August 13th. This shower is active most of the month and remains above the level of the sporadic background for a week centered on August 13th. The sporadic activity is also near maximum as seen from the Northern Hemisphere and is now more than double the rates from just three months ago. As seen from the Southern Hemisphere, meteor rates are still decent but falling rapidly. The sporadic rates continue their downward slide plus the Perseid radiant does not rise high into the sky as seen from south of the equator. Therefore, rates for the Perseids are greatly reduced when compared to those seen from the Northern Hemisphere.

During this period the moon will reach its last quarter phase on Thursday August 6th. At that time the moon will be located 90 degrees west of the sun in the sky and will rise near midnight local standard time. This entire week the waning gibbous moon will rise during the evening hours and will fill the sky with bright moonlight the remainder of the night. Under such conditions it will be difficult to observe meteor activity as only the brightest meteors will be visible.

This week evening observers can expect total hourly rates of 3 from mid-northern latitudes (45°N) and near 2 from tropical southern locations (25°S). Morning observers may see rates near 15 from mid-northern latitudes and near 14 from tropical southern locations. Rates will be less than the listed figures if skies are hazy.

The actual rates observed 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 based on observations 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 from which meteors appear to originate) positions and rates listed below are exact for Saturday night/Sunday morning, August 1/2. These positions do not change greatly from day to day, so the listed coordinates may be used throughout this entire period. Most star atlases (available online, in bookstores, and at planetariums) include maps with celestial coordinate grids that can help you locate these positions 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 represents the sky directly overhead at the corresponding hour. These charts are oriented towards facing south but can be used for any direction by rotating them accordingly. A planisphere or planetarium app is also useful for 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 (culmination), either due north or south along the meridian, depending on your latitude. Radiants that rise after midnight will not reach their highest point until daylight; therefore, it is best to view them during the last few hours of the night.

It must be remembered that meteor activity is rarely seen directly at the radiant position. Rather, meteors shoot outward from the radiant, so it is best to center your field of view so that the radiant lies near the edge rather than the center. Viewing in this way allows you to trace the path of each meteor back to the radiant (if it belongs to a shower) or in another direction if it is sporadic. Meteor activity is not visible from radiants located far below the horizon.

The positions below are listed in west-to-east order by right ascension (celestial longitude). The positions listed first are located farther west and are therefore accessible earlier in the night, while those listed farther down the list rise later.


Radiant Positions at 23:00 Local Sumer Time

Radiant Positions at 01:00 Local Sumer Time

Radiant Positions at 03:00 Local Sumer Time

 

The following sources of meteoric activity are expected to be active this week:

Details of each shower will continue next week when viewing conditions are more favorable

Rates and positions on the table are exact for Saturday night/Sunday morning August 1/2.

SHOWER DATE OF MAXIMUM  CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
 ACTIVITY RA (RA in Deg.) DEC Km/Sec Local Summer Time North-South
kappa Cygnids (KCG) Aug 14 18:36 (279) +42 20 23:00 <1 – <1 II
July gamma Draconids  (GDR) Jul 28 18:36 (279) +51 26 00:00 <1 – <1 II
alpha Capricornids (CAP) Jul 30 20:32 (308) -09 22 01:00 2 – 2 II
Anthelion (ANT) _ 21:28 (322)  -15 30 02:00 <1 – 1 II
August beta Piscids (BPI) Aug 22 22:24 (336) -02 38 03:00 <1 – <1 IV
Southern delta Aquariids (SDA) Jul 30 22:48 (342) -16 41 04:00 2 – 3 I
Perseids (PER) Aug 13 02:16 (034) +56 59 06:00 4 – 3 I
eta Eridanids (ERI) Aug 05 02:32 (038) -14 64 07:00 1 – 1 II
July chi Arietids (JXA) Jul 17 03:08 (047) +15 69 08:00 <1 – <1 IV

Class Explanation: A scale to group meteor showers by their intensity:

  • Class I: the strongest annual showers with Zenith Hourly Rates normally ten or better.
  • Class II: reliable minor showers with ZHR’s normally two to ten.
  • Class III: showers that do not provide annual activity. These showers are rarely active yet have the potential to produce a major display on occasion.
  • Class IV: weak minor showers with ZHR’s rarely exceeding two. The study of these showers is best left to experienced observers who use plotting and angular velocity estimates to determine shower association. These weak showers are also good targets for video and photographic work. Observers with less experience are urged to limit their shower associations to showers with a rating of I to III.