Geminid Meteor shower tonight

The Moon rises at 1.30 EST and will wash out the skies, but before then it could be good.

http://www.cnn.com/2006/TECH/space/12/12/meteor.shower/index.html

Here's the official International Astronomical Union announcement for your reading pleasure:

Subject: CBET 773: 20061212 : GEMINID AND URSID METEORS 2006

Electronic Telegram No. 773

Central Bureau for Astronomical Telegrams

INTERNATIONAL ASTRONOMICAL UNION

M.S. 18, Smithsonian Astrophysical Observatory

Cambridge, MA 02138, U.S.A.

IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)

CBAT@CFA.HARVARD.EDU (science)

URL http://cfa-www.harvard.edu/iau/cbat.html

GEMINID AND URSID METEORS 2006

P. Jenniskens, SETI Institute, reports that the Geminid meteors from (3200) Phaethon should peak at ZHR = 130 +/- 20 meteors/hr on 2006 Dec. 14d08h48m UT, with a FWHM of 26 hr (Jenniskens 2006, Meteor Showers and Their Parent Comets, Cambridge Univ. Press, p. 397). A waning 31-percent crescent moon will not interfere before 1 a.m. local time. Meteors should radiate from a geocentric radiant of R.A. = 113.8 deg, Decl. = +32.4 deg (equinox 2000.0), with velocities of V_g = 34.6 km/s. On average, Geminids are fainter in the days leading up to the peak than they are following the peak; at its peak, the magnitude-distribution index (cf. CBET 710) is predicted to be chi = 2.7.

Jenniskens adds that E. Lyytinen and M. Nissinen (Helsinki, Finland) have identified an encounter of the earth with the 75-revolution dust trail (dating back to 996 AD) of comet 8P/Tuttle around 2006 Dec. 22d19h27m UT, with meteoroids in the earth's path between 18h10m and 20h50m, depending on the adopted value for nongravitational acceleration (this updates Jenniskens 2006, Meteor Showers and their Parent Comets, Cambridge Univ. Press, p. 641).

A 6-percent moon in Cap will not interfere. Meteors should radiate from a geocentric radiant of R.A. = 217.56 deg, Decl. = +74.93 deg (equinox

2000.0), with velocities of V_g = 33.83 km/s. Particles could be mostly faint with a magnitude-distrubtion index of chi around 2.8. A predicted peak rate of ZHR around 35 meteors/hr would be about three times that of the annual Ursids. The calculations assume that, back in 996 AD, 8P/Tuttle behaved much as it does now. The previous oldest trail traced into the earth's path (in AD 2000) is dated to AD 1405. The meteoroid orbits are not strongly perturbed by Jupiter, so that the meteoroids tend to accumulate over time in a component called a "filament" (such filaments are known from comets 109P, 55P, 1P, and 8P). Jenniskens also points out that it is possible that a broader (FWHM = 8.5 hr) filament dust component will return, peaking at around 2006 Dec. 22d17h38m with ZHR around 39 meteors/hr and with chi = 2.6. That filament was seen before 1982 and in 1993-1998, during previous returns of the comet to perihelion. The 1945 display was identified by Jenniskens et al. (2002, Icarus 159, 197-209) as due to a more-or-less well-behaved dust trailet ejected in 1392; the calculated peak time of the shower was 1945 Dec. 22d18h29m UT, close to the time of the observations. Comet 8P/Tuttle is due back at perihelion on 2008 Jan. 26.9 TT (MPC 54167).