Meteor Activity Outlook for 8-14 April 2023

Catherine Perkinton was out photographing a colorful aurora display when this brilliant fireball shot through the field of view of the camera. This occurred on September 4, 2022, at 23:46 BST (22:46 UT ) as seen from Kentallen, Scotland, United Kingdom.  Notice the bright pattern of the Big Dipper in the upper portion of the photograph with the fireball passing close to the star known as Alkaid (eta Ursae Majoris).  ©Catherine Perkinton

During this period, the moon reaches its last quarter phase on Thursday April 13th. At that time the half-illuminated moon will be positioned 90 degrees west of the sun and will rise near 04:00 local summer time (LST). This weekend the waning gibbous moon will rise during the late evening hours allowing an opportunity to view meteor activity under dark skies between dusk and moon rise. The estimated total hourly rates for evening observers this week should be near 3 as seen from mid-northern latitudes (45N) and 4 as seen from tropical southern locations (25S) For morning observers, the estimated total hourly rates should be near 4 as seen from mid-northern latitudes (45N) and 7 as seen from tropical southern locations (25S). The actual rates seen will also depend on factors such as personal light and motion perception, local weather conditions, alertness, and experience in watching meteor activity. Morning rates are reduced due to bright 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 April 8/9. 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 its 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.

This source of meteoric activity is expected to be active this week.

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The large Anthelion (ANT) radiant is currently centered at 14:08 (212) -13. This position lies in southeastern Virgo, 3 degrees northeast of the 4th magnitude star known as Kang (kappa Virginis). Due to the large size of this radiant, these meteors may also be seen from Libra as well as eastern Virgo. This radiant is best placed near 02:00 LST when it lies on the meridian and is highest in the southern 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.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 3 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 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 3 per hour during the evening hours. Morning rates are reduced by moonlight during this period.

The list below offers the information in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.

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.