BAA Circular 00128: Ursid Meteor Shower

[Rick]

(Slightly censored for public posting - Rick)

Observations Required - 2003 Ursid Meteor Shower

Active between December 17 and 25, the Ursid meteor shower is associated with Comet 8P/Tuttle. In most years, activity is relatively modest, with observed rates under reasonable conditions typically 5-6 meteors/hr at best, corresponding to a corrected Zenithal Hourly Rate of the order of 10-12.  While comparable in strength to April's Lyrids, the Ursids attract much less attention than that shower, in part due to their proximity to Christmas. For observers seeking release from the seasonal pressures, however, perhaps a couple of hours' meteor watching during the 2003 Ursids provides a productive alternative occupation in  late evening!

The 2003 Ursids are favoured by the absence of moonlight: New Moon is on December 23. Another beneficial factor is that the radiant, from which Ursid meteors will appear to emanate, is circumpolar at UK latitudes, meaning that observations are  possible at any time of night. Located at RA 14h 28m Dec +78o, the radiant lies close to Beta Ursae Minoris - one of the 'Guardians of the Pole' - and will be at its highest in the early morning hours.

Ursid meteors are generally faint and medium-paced (geocentric velocity 33 km/s). Peak activity is expected on Monday-Tuesday December 22-23, but watches at other times will also be welcomed. Normally a low-activity (but still significant) shower, the Ursids can on occasion produce outbursts of higher rates. The last well-documented outburst occurred in 1986 as seen by observers in mainland Europe, while UK-based watchers were surprised to record rates of 15-20 meteors/hr on 1982 Dec 22-23. Other outbursts may well have been missed in the past -  a lack of consistent, year-on-year coverage rather emphasises the need to acquire quality data on the Ursids when favourable opportunities such as that in 2003 arise.

Observations made by the Meteor Section's standard methods outlined on the Web pages at http://britastro.com/meteor will be welcomed by the Director.

Early reports from last weekend's Geminid maximum bear out the forecast (BAA e-circular 126) of good rates on Sunday-Monday December 14-15, with the expected healthy crop of bright meteors and fireballs among the meteors seen; several reports of fireballs seen by members of the public have been received at the BAA Head Office. Visual observed rates of 20-25 Geminids/hr were reported by several watchers in southern England around 21h UT - before moonrise - on Dec 14-15. In the rise towards Sunday's mid-morning maximum, Jonathan Shanklin, observing under moonlit conditions at Cambridge, reports over 50 Geminids in 2.5 hours' observing after midnight on Dec 13-14. It would certainly appear that the Geminids once again produced excellent rates in 2003.

The Director extends his good wishes for Christmas 2003 and a successful 2004 with abundant meteor observing opportunities to all readers of the BAA Electronic Circulars.

Neil Bone, Director, BAA Meteor Section.
http://britastro.com/meteor


[ This Message was edited by: Rick on 2003-12-18 11:20 ]