Meteor Activity Outlook for 21-27 October 2023

Mike Lewinski captured this bright fireball at 00:48 MDT on April 6, 2023 (06:48 UT), from Crestone, Colorado USA. While it looks like daytime it’s actually the full moon illuminating the landscape. ©Mike Lewinski

During this period, the moon reaches its first quarter phase on Sunday October 22nd. At this time is will actually set near 2200 local summer (LST) on October 21st. As the week progresses, the moon will intrude into the morning sky, limiting the availability of dark skies. By the end of this period the moon will lie above the horizon all night long. The estimated total hourly rates for evening observers this week should be near 3 as seen from mid-northern latitudes (45N) and 2 as seen from tropical southern locations (25S) For morning observers, the estimated total hourly rates should be near 35 as seen from mid-northern latitudes (45N) and 25 as seen from tropical southern locations (25S). Evening rates are reduced by moonlight. 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. 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 October 21/22. 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. 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 Northern Taurids (NTA) are active from a radiant located at 02:40 (040) +18. This area of the sky is located in central Aries, 4 degrees north of the brilliant planet Jupiter. To best see these meteors, one should face southward near 01:00 LST. Note that this radiant is only 6 degrees north of the STA radiant so care must be taken to separate these two showers. Maximum activity is not until November 12^th so rates at this time should be near 1 per hour no matter your location. With an entry velocity of 29 km/sec., the average NTA meteor would be of medium-slow velocity.

The Southern Taurids (STA) are active from a wide radiant centered near 02:44 (041) +12. This position lies in southern Aries, 2 degrees north of the 4^th magnitude star known as mu Ceti. This position also lies 2 degrees southeast of the brilliant planet Jupiter. These meteors are best seen near 01:00 LST when the radiant lies highest in the southern sky. Rates are expected to be near 3 per hour no matter your location. With an entry velocity of 27 km/sec., the average STA meteor would be of medium-slow velocity.

The October zeta Perseids (OZP) produced a short-lived outburst centered at 21:00 Universal Time on October 24, 2021. That outburst only lasted three hours and was witnessed over Europe. If a repeat performance occurs in 2023, it is expected to peak near 9:00 UT on October 25^th. This timing favors North America with the timing ranging from 3am EDT to midnight PDT on October 25th. The radiant is located at 03:53 (058) +34, which is located in southern Perseus, 3 degrees northwest of the 3^rd magnitude star known as zeta Persei. A total of 14 bright meteors were recorded in 2021 on video cameras operated by the Global Meteor Network*. Undoubtedly there were many more to be seen. If a repeat performance occurs, no matter your location, it would be best to face toward the northeast at the times mentioned above. Other areas in the northern hemisphere are encouraged to also try and verify any activity from this source on the nights of October 23-26. At 48km/sec., most of these meteors would possess medium-swift velocities.

*October zeta Perseid meteor shower (OZP #1131), posted by Denis Vida, Global Meteor Network, https://www.meteornews.net/2021/10/28/october-zeta-perseid-meteor-shower-ozp01131/

The Orionids (ORI) are active from September 26 through November 22, with maximum activity occurring on October 22nd. The radiant is currently located at 06:21 (095) +16, which places it in northeastern Orion, 2 degrees northeast of the 4^th magnitude star known as xi Orionis. This area of the sky is best placed for observing during the last dark hour prior to dawn, when it lies highest in the southern sky.  Current rates are expected to be near 15 per hour as seen from the northern hemisphere and near 12 as seen from south of the equator. With an entry velocity of 66 km/sec., the average ORI meteor would be of swift velocity.

The epsilon Geminids (EGE) are active from September 27 through November 8 with maximum activity occurring on October 19^th. The radiant is currently located at 07:04 (106) +28. This area of the sky lies in central Gemini, 2 degrees southwest of the 4th magnitude star known as tau Geminorum. To best see these meteors face toward the southeast during the last dark hour prior to dawn. Rates at this time should be near 2 per hour as seen from the northern hemisphere and one as seen from south of the equator. With an entry velocity of 70 km/sec., the average EGE meteor would be of swift velocity.

The Leonis Minorids (LMI) are active from October 13^th to November 3^rd, with maximum activity occurring on October 22nd. The radiant is located at 10:40 (160) +38, which places it in northeastern Leo Minor, 3 degrees northeast of the 4th magnitude star known as beta Leonis Minoris. These meteors are best seen by facing toward the east during the last couple of hours prior to dawn. This shower is better for observers situated in the northern hemisphere where the radiant rises far higher into the northeastern sky before the start of morning twilight. Current rates should be near 2 per hour from the northern hemisphere and less than 1 from south of the equator. At 62km/sec., the average Leonis Minorid is swift. From my personal experience this minor shower produces a high proportion of bright meteors.

Sporadic meteors are those meteors that cannot be associated with any known meteor shower. All meteor showers are evolving and disperse over time to the point where they are no longer recognizable. Away from the peaks of the major annual showers, these sporadic meteors make up the bulk of the activity seen each night. As seen from the mid-northern hemisphere (45N) one would expect to see during this period approximately 10 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates should be near 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 7 per hour as seen from rural observing sites and 1 per hour during the evening hours. Locations between these two extremes would see activity between these 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.

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.