Meteor season finally gets going in July for the northern hemisphere. The first half of the month will be much like June with predominately slow rates. After the 15th though, both sporadic and shower rates increase significantly. For observers in the southern hemisphere, sporadic rates will be falling but the overall activity will increase with the arrival of the Southern delta Aquariids during the last week of the month.
During this period, the moon reaches its last quarter phase on Thursday July 1st. This weekend the nearly full moon will lie above the horizon most of the night, spoiling viewing conditions for meteor observers. As the week progresses, evening conditions improve as the moon rises later with each passing night. This allows a small window of opportunity to view under dark skies between dusk and moon rise. The estimated total hourly meteor rates for evening observers this week is 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 4 as seen from mid-northern latitudes (45N) and 6 as seen from tropical southern locations (25S). 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. Rates are reduced by moonlight during this period. 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 June 26/27. 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 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.
Detailed information on each source will continue next week when viewing conditions improve.
|SHOWER||DATE OF MAXIMUM ACTIVITY||CELESTIAL POSITION||ENTRY VELOCITY||CULMINATION||HOURLY RATE||CLASS|
|RA (RA in Deg.) DEC||Km/Sec||Local Summer Time||North-South|
|June Bootids (JBO)||Jun 27||14:56 (224) +28||18||22:00||<1 – <1||III|
|Anthelion (ANT)||–||19:12 (288) -22||30||02:00||1 – 2||II|
|Northern June Aquilids (NZC)||Jul 15||20:21 (305) -07||40||03:00||<1 – <1||IV|
|Microscopiids (MIC)||Jul 06||20:41 (310) -28||40||03:00||<1 – <1||IV|
|June iota Pegasids (JIP)||Jun 25||22:36 (339) +30||61||05:00||<1 – <1||IV|
|phi Piscids A (PPS)||Jun 24||00:46 (011) +22||67||08:00||<1 – <1||IV|
|c-Andromedids (CAN)||Jul 12||01:08 (017) +43||57||08:00||<1 – <1||IV|
|July chi Arietids (JXA)||Jul 07||01:36 (024) +03||68||09:00||<1 – <1||IV|