Society for Popular Astronomy

[Alastair McBeath]

December 2009's second full Moon, on the 31st, means a waning gibbous Moon for the Quadrantid maximum, due on January 3, around 19h UT. There is the possibility that a short-lived, quite strong, peak could occur at some stage between roughly 12h to 16h UT that day instead. This alternative timing is of course mostly in daylight for Britain, while the ~19h timing is almost as poor, since the shower's peak is typically short and sharp, and the Quadrantid radiant, though circumpolar from the UK, is nearing its daily lowest then. Add to that the Moon will rise within 15 minutes either side of 20h UT for Britain that evening (later rising times further south), and this means it is highly likely we shall see little of the shower from here this time. The radiant is set in a fairly starless void of northern Boötes on January 3-4 (roughly midway between Hercules' right foot, Boötes' head, Ursa Major's tail-tip and the largest curve of Draco, once part of a now-discarded constellation, the Wall Quadrant, hence its otherwise obscure name). This area of sky is very low to the north during the first half of the night (lowest at about 20:30 UT), and is only properly observable after midnight.

Maximum Zenithal Hourly Rates (ZHRs) from the Quadrantids have been around 120 in recent times, though the highest value does vary somewhat from year to year. It can be as low as 60, or up to 200, and has occasionally persisted for a couple of hours close to its best level. The 2009 maximum return was particularly unusual, as ZHRs of 100+ persisted for about 14 hours, and there may have been several peaks, at least two of which reached ZHR levels of ~130-160. Even in more normal years, the peak time may alter slightly, and some returns since 2000 seem to have produced an additional, primarily radio meteor, maximum about 9-12 hours after the visual one. If this happens again, the well-past-midnight part of January 3-4 may be worth watching on still, if clear skies appear, despite the bright Moon. Note though that while 2008 produced two radio maxima, the first was roughly six hours BEFORE the visual maximum occurred - which itself was about 3 to 4 hours later than expected! Fainter radio and telescopic Quadrantids have been observed to peak up to 14 hours before the main visual event in the past too.

Quadrantids are medium-speed meteors, often reasonably bright near the visual maximum. Much lower numbers of them should be present from about January 1-5, but recent International Meteor Organization (IMO) video results have suggested the shower may remain detectable instrumentally at least from about December 27 or 28 to January 12, a far longer period than previous visual investigations had found. Anyone hopefully intending to brave the moonlight after midnight on January 3-4 should watch as much clear sky as comfortably possible, but looking away from the Moon, and where as little reflected moonlit landscape as possible is near your facing direction.

For more information on January's meteor activity (including links to news from the 2008 and 2009 Quadrantid returns), see:

http://www.popastro.com/sections/meteor/meteor-jan2010.htm .

Be well-prepared for the probable conditions outdoors, good luck and clear skies!

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
Meteor homepage: http://www.popastro.com/sections/meteor.htm
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)

[david entwistle]

[Alastair McBeath]

Thanks for that, David - I've amended my earlier posting now. Copy & paste is fine, so long as you remember to check what you've copied is correct first of all!

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
Meteor homepage: http://www.popastro.com/sections/meteor.htm
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)

[david entwistle]

[Alastair McBeath]

Early reports reaching me from various parts of the UK so far, suggest that even where people had clearer skies on January 3-4, no observers were prepared to chance the often deadly icy conditions underfoot to get to their observing sites, particularly when coupled with the glare from the moonlit snow. Here in Northumberland, I got as far as my back step, which was treacherous enough with ice, and marvelled at the one time the sky's been really clear near a major shower's maximum in more than a year, the limiting magnitude was barely +3.9, thanks to a little haze, a lot of direct and snowfield-reflected moonlight, and an apparently similar amount of snow-bouncing waste streetlighting. I didn't see any meteors, and the far-below-zero temperature wasn't conducive to standing there for very long in the hopes one might chance-by!

However, I have had a couple of fireball sightings, one each on January 2-3 and 3-4, one of which at least may have been a Quadrantid, though a preliminary report of his video data by Enrico Stomeo in Italy found just one fireball on January 2-3 or 3-4, a magnitude -9 sporadic at 02:08 UT on January 4. Enrico's results, plus more video data from Bob Lunsford in California (all kindly forwarded by Rich Taibi in Maryland, unable to watch himself because of still more devastatingly cold temperatures than those in Britain, and very high windchill), suggested healthy Quadrantid activity on January 3 at least. In the absence of any visual data so far - even the International Meteor Organization hasn't its usual "live" shower webpage active for the Quadrantids this year - it's difficult to suggest how the shower may have behaved.

Some radio notes posted on the IMO-News e-mailing list by Japanese observer-analyst Hiroshi Ogawa (mentioned by David) indicated he had found a peak around 16:00-18:00 UT on January 3. However, his method has proven somewhat controversial previously, as it's unclear how the various disparate radio data have been combined into a single numerical value, plus there have been occasions before when insufficient allowance was made for the varying sensitivities of the different radio systems involved, as the shower radiant elevations changed with time.

Of the radio observers reporting directly to us, apart from David, whose data is difficult to interpret for the reasons he mentioned, only Jeff Brower in British Columbia, Canada, has provided detailed radio-echo counts across the expected Quadrantid maximum to date with a useful radiant elevation, and these seemed to favour a peak around 12h-15h UT on January 3 instead. Which was the true peak will likely only become clearer (if indeed that can be achieved), once all the January radio results are in, hopefully by mid February.

If anyone has any Quadrantid meteor data to submit, please do send them along as soon as may be!

Alastair McBeath,
Meteor Director, Society for Popular Astronomy.
Meteor homepage: http://www.popastro.com/sections/meteor.htm
E-mail: <meteor@popastro.com> (messages under 150 kB in size only, please)

[Hampshire Astronomer]

[Hampshire Astronomer]

Start: 18.00 UT End: 21.30 UT Duration: 3 Hours
Time UT Magnitude "Name Shower
or if Sporadic" "Constellation(s)
in which seen" "Train details and
time to fade (secs)" Notes
18.12 -1 Quadrantid Perseus - White
18.28 3.5 Sporadic Lynx - Faint Blue Colouration
19.29 3.5 Quadrantid Ursa Major - Blue, Very Fast
19.56 -1 Quadrantid Cetus - White & Fast
19.56 3.5 Quadrantid Ursa Major - Fast, Pale White
20.13 3 Quadrantid Ursa Minor - Slow, Pale White
- - Break Time 20.30 - 21.00 - -
21.10 4 Sporadic Ursa Major - Pale & Fast
- Watch Finished At 21.30 Due to Moonlight -
_________________
David Scanlan

Director SPA Variable Star section

http://popastro.com/vstar/

[Hampshire Astronomer]

Should have mentioned this was the 3rd January 2010

Apologies

Dave
_________________
David Scanlan

Director SPA Variable Star section

http://popastro.com/vstar/

[Hampshire Astronomer]

Oh....and limiting mag was 5
_________________
David Scanlan

Director SPA Variable Star section

http://popastro.com/vstar/