On the evening of June 11, 1930, three members of the American Meteor Society (AMS) reported that they observed a flurry of meteor activity occurring between the hours of 2215 and 2245 (1015-1045pm EST) from Maryland, USA. These meteors were seen despite the fact that a nearly full moon was present in the sky during the entire display. No other reports of this activity was reported, leading to some doubts of the authenticity of this outburst. Of course one would not expect many meteor observers to be out observing under such unfavorable lunar conditions. In subsequent years this radiant was monitored but no further activity was seen on or near this date.
Peter Jenniskens, in his study of outbursts from long-period comets, has proposed that the 1930 event was real and may be repeated on Tuesday morning June 11, 2013. The expected time of maximum activity would be near 0828 Universal Time. This time corresponds to 4:28am EDT, 3:28am CDT, 2:28am MDT, and 1:28am PDT. This timing is favorable for all the Americas, extending west to the Hawaiian Islands. The radiant was reported to lie near the notable double star gamma Delphini, which lies near celestial coordinates 312 (20:48) +17. For observers in mid-northern latitudes this radiant rises in the eastern sky shortly after the end of dusk and is best placed high in the southern sky between 0400 and 0500 local daylight time.
To view this possible outburst one should seek out the darkest skies possible. Clear horizons devoid of trees and hills would also help. I would suggest starting your viewing session at least two hours prior to the expected maximum, in case it arrives early. While this activity can be seen in any portion of the sky, it would be best to view so that the radiant is included in your field of view so that you can verify if any activity can be associated with this radiant. These meteors would be of medium-swift velocity unless they appear near the radiant or close to the horizon. In these instances any gamma Delphinid meteors would move more slowly.
No one knows the strength of this display or whether it will occur at all. It would most likely be of short duration (less than one hour and perhaps as short as 15 minutes). This is not something one can stand outside and try to witness. Serious observers should be comfortable in a lounge chair and watch for at least an hour. I would not expect strong rates such that occurred with the Leonid outbursts near 2000. Rather these meteors are more likely to appear a minute or two apart. True Gamma Delphinid meteors would be moderately swift unless they appear near the radiant or near the horizon. In these case they would appear to travel with medium velocity. Unlike the 1930 display, the moon will not be a factor in 2013 as it will have set long before the predicted time of the outburst.
If your skies are clear the AMS encourages you to try and verify any activity from this source. Even reports with no activity will help. Be sure to share your observations (either positive or negative) with us as soon as possible after viewing. Reports may be emailed to: firstname.lastname@example.org or one may use the AMS online report form (available to registered members).
American Meteor Society