After the Perseids, the next major shower to occur are the Orionids. This shower is active for six weeks beginning near October 4th. At this time the moon will be a bright waning gibbous that will be located fairly close to the radiant. Even in dark skies rates at this time would most likely be less than one shower member per hour. It would probably make more sense to wait until the weekend of October 13/14, when rates are 1-2 per hour and the slender old moon will not offer any interference. As the moon passes its new phase on October 15th, there will be no lunar interference until the date of maximum activity (Oct 21/22) has passed.
Rates will remain low until the 17th or 18th, when they may reach five per hour as seen when the radiant lies highest in the sky. In 1993 and 1998, strong rates, equivalent to the maximum, were reported near this time. These outbursts were also rich in bright meteors. Even though we are not expecting any early activity, the morning of the 17th may be a good time to start your Orionid observations.
Orionid rates are expected to increase each night up to the night of maximum activity. The weekend of October 20/21 should provide nice activity. The exact maximum is predicted to occur near 0200 Universal Time on October 22nd. The maximum is not sharp so rates may be equally strong on the mornings of the 21st and the 22nd. Rates for the Orionids usually remain good two to three nights after the maximum has passed. Beyond the 25th, the rates will start to subside plus the waxing gibbous moon will now start interfering with observations as it remains in the sky nearly all night.
At the beginning of its activity, the Orionid radiant is located in northern Orion. Near the time of maximum activity it actually crosses the border into Gemini, where it remains until the last of the Orionids are seen in mid-November. As seen from mid-northern latitudes, the Orionid radiant rises in the east near 2200 (10pm) local daylight time. While some â€œearthgrazingâ€ Orionids may be seen at this time, it is suggested that you wait until 0100 to begin serious observations. Of course if rates appear strong with the radiant low in the sky, by all means begin viewing immediately! Normally, decent rates will not begin to appear until the radiant has reached thirty degrees altitude. Since the Orionid radiant is located near the celestial equator, this display will be equally well seen from both hemispheres. The north may have a slight advantage as the nights are longer north of the equator that time of year.
While Orionid meteors may be seen in any portion of the sky, I usually end up facing due south and let the radiant swing though the upper portion of my field of view. This allows me to also follow the Taurids, Epsilon Geminds, and any other potential radiant that happens to be within my field of view. If you also do some research beforehand, you can memorize the positions of radiants in the northern sky and trace any meteors that enter your field of view back to their source.
Not many showers peak on a weekend so take advantage of this opportunity and let us know what you see!