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The major meteor event in December is the Geminids but there's another shower later in the month, the Ursids, that doesn't make as many headlines but on occasions can be quite good. With the radiant located close to the north pole star, the Ursids are a northern shower. They are nowhere near as spectacular as the Geminids, but on occasions have shown significant bursts of activity and a re-occurrence may occur any year.

This year, the shower peak occurs on the night of December 22 / 23 and the four day old waxing crescent Moon won't significantly interfere.

Comet 8P/Tuttle and M33 The Triangulum Galaxy (credit:- Paul Martinez / Philip Brents)

Parent comet

The comet that sources and therefore is responsible for the shower is 8P/Tuttle (also known as Tuttle's Comet or Comet Tuttle). It has a period of 13.6 years and during the last perihelion on January 27, 2008 was visible telescopically. On January 1, 2008, it passed Earth at a distance of 0.25282 AU (37,821,000 km or 23,501,000 miles) and anticipation was high for the 2007 and 2008 showers, but in the end only a small increase in activity was observed.

Radiant

The radiant for the Ursids meteors is located in the constellation of Ursa Minor. With a declination of +76 degrees, it's circumpolar from most northern locations. However on the other hand, it fails to rise from many southern sites. Positioned just a couple of degrees southeast of the radiant is Kochab (β UMi - mag. +2.1).

Ursids Radiant and Star Chart (credit:- freestarcharts)

Ursids Radiant and Star Chart - pdf format

What to expect

The best night to look for the Ursids is on December 22 / 23. Normally, it has a zenithal hourly rate (ZHR) of 10, although there have been at least two major outbursts in the past 80 years (1945 and 1986). During an outburst more than 50 meteors per hour have be seen, propelling the shower into the realms of the better annual showers.

When observing meteors they can streak through the sky many degrees from the radiant, so it's better to scan a large area of surrounding sky. To confirm an Ursid, trace the meteor backwards and it will go all the way to the radiant.

Looking north just after midnight from mid-northern latitudes on December 23rd (credit:- freestarcharts/stellarium)

Ursids 2017 Data Table

Meteor shower nameUrsids
Radiant ConstellationUrsa Minor
Dates17th December -> 26th December
Peak Date22nd December
RA (J2000)14hr 28m
DEC (J2000)+76d
Speed (km/s)33
Zenithal Hourly Rate (ZHR)10 (occasionally up to 50)
Parent8P/Tuttle (comet)