Meteor Activity Outlook for 27 May-2 June 2023

Chris Hall captured this multi-bursting fireball while photographing this homestead on June 19, 2020, at 00:48 CDT (5:43 UT) from rural Oklahoma, USA. Congratulations to Chris on her excellent timing! ©Chris Hall

During this period, the moon reaches its first quarter phase on Saturday May 27th. On that date it will set near 02:00 local summer time (LST) allowing the remainder of the night to be free of interfering moonlight. As the week progresses, the moon will soon become a major problem as it remains above the horizon most of the night and obscures the fainter meteors with bright moonlight. 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 8 as seen from mid-northern latitudes (45N) and 13 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 during this period 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 27/28. 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.

These sources of meteoric activity are expected to be active this week.

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The center of the large Anthelion (ANT) radiant is currently located at 17:20 (260) -23. This position lies in southeastern Ophiuchus, 2 degrees northwest of the 3rd magnitude star known as theta Ophiuchi. Due to the large size of this radiant, Anthelion activity may also appear from western Sagittarius as well as southern Ophiuchus. This radiant is best placed near 0100 LST, when it lies on the meridian and is located highest in the sky. Rates at this time should be near 1 per hour as seen from the Northern Hemisphere and 2 per hour as seen from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The Daytime Arietids (ARI) are active from May 14-June 24 with maximum activity occurring on June 7th. These meteors are difficult to catch as the radiant only lies 30 degrees west of the sun. Therefore, the only time these meteors are visible is during the last dark hour before dawn. Any member of this shower will be see shooting from low in the eastern sky just prior to dawn. The radiant is currently located at 02:28 (037) +24. This area of the sky is located in northwestern Aries, 4 degrees northeast of the 2nd magnitude star known as Hamal (alpha Arietis). Current rates are expected to be less than 1 no matter your location. With an entry velocity of 39 km/sec., the average meteor from this source would be of medium velocity. For radio observers, this is the best time of the year to hear and detect daytime meteors. Radio rates will be increasing now and will peak during the second week of June when this shower and the Daytime zeta Perseids reach maximum activity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 6 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 10 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. Evening rates are reduced due to moonlight.

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.