During this period the moon reaches its last quarter phase on Wednesday May 14th. At this time the half-illuminated moon will lie 90 degrees west of the sun and will rise near 0100 local daylight time as seen from mid-northern latitudes. The moon will interfere with meteor observations as the glare will obscure fainter meteors. This weekend the waning gibbous will seriously compromise meteor observing as it will lie above the horizon most of the night. Toward the end of this period conditions will not be nearly as unfavorable as the waning crescent moon will be less bright and will rise later in the morning. The estimated total hourly meteor rates for evening observers this week is near 2 for observers situated at mid-northern latitudes and 3 for observers viewing from the southern tropics (latitude 25 S.). For morning observers the estimated total hourly rates should be near 4 for observers situated at mid-northern latitudes and 6 for observers viewing from the southern tropics. The actual rates 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 this week due to interfering 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 brightest 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 17/18. 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. 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 the 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 a sporadic. Meteor activity is not seen from radiants that are located 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. Details of each source will continue next week when more favor observing conditions exist.
Special Note: Recent observations indicate that members of the Camelopardalids may be appearing before their predicted outburst on May 24th. There have been several videos of fireballs posted that display a radiant and velocity similar to what would be expected of Camelopardlid meteors. These meteors are best seen during the late evening hours before moonrise. They may appear in any portion of the sky but would all track back to a point in the obscure constellation of Camelopardalis. The radiant point lies approximately 10 degrees from the North Star, also known as Polaris. This area lies just above Polaris at sunset and slowly rotates downward to the left of Polaris as the night progresses. Your best chance of seeing any activity would be to simply face northward once it becomes totally dark. Unfortunately observers south of the equator cannot witness much activity from this radiant as it lies either very low in the northern sky or below the horizon. Since evening meteor activity this time of year is normally low, any slow moving meteors have a good chance of belonging to this display. Do not confuse meteors with satellites, which are numerous this time of night. The easiest way to tell the difference is that meteors will last only a matter of seconds while satellites are usually visible for over a minute and appear like moving stars.
|SHOWER||DATE OF MAXIMUM ACTIVITY||CELESTIAL POSITION||ENTRY VELOCITY||CULMINATION||HOURLY RATE||CLASS|
|RA (RA in Deg.) DEC||Km/Sec||Local Daylight Time||North-South|
|Camelopardalids (CAM)||May 24||08:08 (122) +79||19||18:00||<1 – <1||III|
|Anthelions (ANT)||–||16:40 (250) -22||29||02:00||1 – 1||II|
|Eta Aquariids (ETA)||May 07||23:04 (346) +03||68||09:00||1 – 2||I|