Meteor Activity Outlook for 3-9 May 2025

Moises Duran captured this brilliant fireball on November  13, 2024, at 0200 CST (08:00 UT) from La Laja, Jalisco, Mexico. ©Moises Duran

May is the best spring month (in the northern hemisphere) to view meteor activity. The eta Aquariids are very active the first two weeks of the month then fade as the month progresses. These meteors are only visible in the few dark hours prior to dawn. The remainder of the night has low meteor rates. The only other showers of note this month are the eta Lyrids and the Anthelion radiant. These will add only 2-3 meteors per hour to the total count. Sporadic rates are low but steady as seen from the mid-northern hemisphere (45 N). Sporadic rates seen from the tropical southern latitudes (25 S) are strong and remain so the entire month.

During this period, the moon reaches its first quarter phase on Sunday May 4th. At that time the moon will lie 90 degrees east of the sun and will set near 03:00 local summer time (LST). The estimated total hourly rates for evening observers this weekend should be near 2 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 16 as seen from mid-northern latitudes (45N) and 30 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. Evening rates are reduced due to 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 May 3/4. These positions do not change greatly day to day so the listed coordinates may be used during this entire period. Most star atlases (available online and at bookstores 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. Radiants that rise after midnight will not reach their highest point in the sky until daylight. For these radiants, it is best to view them during the last few hours before dawn. 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 toward 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 large Anthelion (ANT) radiant is currently centered at 15:44 (236) -20. This position lies in eastern Libra, 5 degrees west of the 2^nd magnitude star known as beta¹ Scorpii. This radiant is best placed near 01:00 LST when it lies on the meridian and is highest in the southern sky. Rates at this time should be near 1 per hour as seen from the northern hemisphere and 2 as seen from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of medium-slow velocity.

The eta Lyrids (ELY) are active from May 6-15 with maximum activity occurring on the 10th. The radiant is currently located at 19:00 (285) +43. This area of the sky is located in northeastern Lyra, 4 degrees northwest of the 4th magnitude star known as eta Lyrae. The radiant is also located 6 degrees northeast of the brilliant zero magnitude star known as Vega (alpha Lyrae). This radiant is best placed during the last hour before dawn when it lies highest above the horizon in a dark sky. Current rates are expected near 1 per hour as seen from the northern hemisphere and less than 1 and seen from south of the equator. These meteors are not well seen from locations south of the equator as the radiant does not rise very high into the northern sky. With an entry velocity of 43 km/sec., the average meteor from this source would be of medium velocity.

The eta Aquariids (ETA) are active from April 15 through May 27 with maximum activity expected on May 6^th. The radiant is currently located at 22:27 (337) -02. This area of the sky is located in northeastern Aquarius, 2 degrees south of the 4th magnitude star known as zeta Aquarii. These meteors are not visible prior to 0100 LST and are best seen just before the start of dawn when the radiant lies highest in the eastern sky. Hourly rates are expected to be as high as 20, but this depends on your latitude. Southern tropical areas are favored with decreasing rates as one moves northward. Mid-northern observers will probably see 5-10 per hour at best. With an entry velocity of 65 km/sec., the average meteor from this source would have a swift velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 5 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 1 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 8 per hour as seen from rural observing sites and 2 per hour during the evening hours. Evening rates are reduced by moonlight during this period.

The list below offers the information in tabular form. Rates and positions in the table are exact for Saturday night/Sunday morning.

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.