Quadrantids 2012: Peak Activity Rate

This morning (Wednesday 04 January 2012) at  around 0530 the Quadrantids meteor shower reached its peak activity rate. According to the International Meteor Organisation the ZHR(max) was 78 +/- 7. As is usual with this meteor shower the peak was quite narrow, with activity starting to increase after 0000 on 04 January, and dropping off again by 1800 the same day.

Quadrantid Meteor Shower 2012, credit imo.net

As was predicted, observers who were out under clear skies between 0430 and 0630 would have got the best views, as within this two hour window the Moon had set and the Sun had yet to brighten the sky. The ZHR(max) of 78 was rather disappointingly low compared with the predicted maximum rate of ~120, but predicting these things isn’t an exact science. The IMO estimated that the rate usually falls somewhere between 60 and 200, so this year’s shower was certainly at the lower end of that, however that might be down to the fact that few people had clear skies (a common problem at this time of year) and so some meteors were missed.

A ZHR (max) occurring at 0530 on 04 January 2012, when the radiant was around 60° above the eastern horizon (in the UK), if seen from a cloudless dark sky site with no light pollution (i.e. a limiting magnitude of 6.5) would have meant that you’d have seen around 70 shooting stars an hour, still quite an impressive show

Quadrantids Meteor Shower 2012

On the night of 03/04 January 2012 the first meteor shower of the year will take place, the Quadrantids. This shower ranks as one of the best performers of the year, assuming your skies aren’t clouded, as they so often are in winter. If the peak of this shower occurs under ideal conditions – i.e. perfectly clear skies, free from light pollution – then you can expect to see in excess of 100 meteors every hour. The peak for this shower is very brief though, so you’ll have to catch just the right conditions at just the right time to see a display this good. This year’s peak is estimated to occur just before dawn on 04 January 2012.

Not only do you have the weather to contend with, but this year the waxing gibbous Moon will be up for much of the night. However the Moon sets at around 0415, giving you a couple of hours before the sky starts to brighten before sunrise. Given that the peak of this shower will probably occur within this short window, things are looking pretty good for this year’s display.

Last year’s graph of meteor activity shows how sharp the peak is, so you probably won’t see many Quadrantids on the nights either side of the peak, but it’s worth a look if you have clear dark skies. ZHR for this year may be anywhere between 60 and 200.

Quadrantids Activity from 2011, credit imo.net

How best to view the Quadrantids 2012

1. Get somewhere as far from street lights and city glow as possible, preferably somewhere really dark, like your nearest national park or one of the UK’s dark sky places: Galloway Forest Park, Sark or Exmoor.
2. Go out at the right time, which for this year’s shower is between around 0400 and 0700 GMT.
3. You don’t need binoculars or a telescope, your eyes are best for viewing meteors.
4. Wrap up warm, as if you have clear skies (which you’ll be hoping for) it will be very cold in these early morning hours.
5. Bring a reclining deck chair so you don’t have to stand all night, and a blanket to wrap yourself in!
6. Although the radiant of the meteor shower (the point where the meteors will appear to stream from) is high in the E around 0400 you don’t need to worry about facing in any particular direction, just position yourself so that you can see as much sky as possible, and enjoy the view!

You can follow the progress of the meteor shower at meteorwatch.org, or on twitter via @VirtualAstro and the #meteorwatch hashtag.

If you want to make more serious observations of this shower you can submit them to either the International Meteor Organisation, the British Astronomical Association, or the Society for Popular Astronomy.

Meteor Showers for 2011-2012: Ones to watch

With the Quadrantids meteor shower that has just past yielding around 100 meteors per hour in near-perfect New Moon conditions, which showers of the next two years will give us as good a display?

Meteor Shower

There are a few regular, dependable showers that can be relied on to put on a good show year after year, given a good Moon phases, so let’s concentrate on those:

Lyrids 2011
The Lyrids peak this year on April 21/22, only three days after the Full Moon, making conditions far from ideal. The ZHR is around 20, but under bright Moon conditions this will be much reduced, so that from the UK you might only see a few Lyrids per hour.

Persieds 2011
The Perseids peak on 12/13 August 2011 coincides exactly with a Full Moon, making this shower pretty much a write-off in 2011.

Orionids 2011
The Orionids peak occurs on 21/22 October 2011 just after the last quarter Moon, with the Moon rising a little after midnight, just as the meteor shower radiant is gaining height. Again, far from ideal.

Leonids 2011
The Leonids peak on 17/18 November occurs during a last quarter Moon, which unfortunately is smack bang in the direction of Leo, and so will obscure many of the Leonids in 2011

Geminids 2011
The Geminids peak on 13/14 December 2011 will likewise be completely obscured by an almost-full Moon in Gemini.

Quadrantids 2012
The Quadrantids peak on 3/4 January 2012 will feature a waxing gibbous Moon which won’t set until 0400.

Lyrids 2012
The Lyrids peak on 21/22 April 2012 is the first major shower peak in 15 months where the Moon is absent, meaning that you should get good views of this shower which has a ZHR of only around 20.

Persieds 2012
The Perseids peak of 12/13 August 2012 will feature a thin waning crescent moon that’s visible in the sky from midnight, obscuring some of the Perseids. Here’s my up-to-date guide to the Perseids 2012.

Orionids 2012
The Orionids peak on 21/22 October 2012 is pretty much Moon-free from around 2330, as the Moon sets.

Leonids 2012
The Leonids peak on 17/18 November 2012 will also be Moon free from early evening, and so presents an opportunity to see a few Leonids.

Geminids 2012
Rounding off this two year run of poor Moon conditions for meteor showers, we end with the Geminids on 13/14 December, coinciding wonderfully with a New Moon on 13 December, meaning conditions will be near perfect.

Quadrantids Meteor Shower 2011: What You Might See

The first meteor shower of 2011 is the Quadrantids, the peak of which falls on the night of the 03/04 January 2011. The Quadrantids shower has one of the highest predicted hourly rates of all meteor showers, comparable to the two great annual showers, the Perseids and the Geminids, occurring in August and Deember respectively. However unlike the Perseids and Geminids, the Quadrantids peak is very narrow, occurring over just a few short hours.  (You can read the IMO’s rather technical summary of the 2011 Quadrantids here: http://www.imo.net/calendar/2011#qua)

The predicted Zenith Hourly Rate (see my previous post about ZHR and what it actually means here) for the Quadrantids is around 120. The narrow peak is predicted to occur some time between 2100 on 3 January and 0600  on 4 January 2011, however the radiant of the shower – the now-defunct constellation Quadrans Muralis – is very low in the evening hours, rising higher towards dawn, and so the best viewing times are later in this run, just before dawn.

The radiant will rise due N and get to its highest before dawn due E, so look roughly in a NE direction to maximise your chance of seeing some Quadrantids. As always with meteor showers, don’t use binoculars or a telescope – your naked eyes are best. One very useful bit of equipment is a reclining deck chair, which makes observing so much more comfortable!

Let’s use the equation relating ZHR to actual observations of meteors to work out how many Quadrantids you might see:

Actual Hourly Rate = (ZHR x sin(h))/((1/(1-k)) x 2^(6.5-m)) where

h = the height of the radiant above the horizon

k = fraction of the sky covered in cloud

m = limiting magnitude

In the case of the 2011 Quadrantids, if observed from the UK, h = 15 degrees at 2100, rising to 25 degrees at midnight, 40 degrees at 0300, and 65 degrees at 0600. Let’s assume you have clear skies (haha) with k = 0.

The number of Quadrantids you can expect to see from a variety of observing sites, at various times throughout the night, is as follows:

For very light polluted sites, such as city centres, m = 3, and therefore you can expect to see between 3 and 10 meteors per hour at the peak, depending on when it occurs.

In suburban skies near a city or town centre m = 4, and you’ll see between 5 and 20 meteors per hour at the peak, depending on when it occurs.

In rural skies where m = 5, you’ll see between 11 and 38 meteors per hour at the peak, depending on when it occurs.

Under very dark skies, where m = 6.5 (i.e. where there is no or negligible effect of light pollution, like in Galloway Forest Dark Sky Park) you’ll see anywhere between 31 and 109 meteors per hour at the peak, depending on when it occurs.

Remember, all of these numbers assume perfectly clear skies. If half your sky is cloudy, cut these numbers in half!

Also remember that it depends when the peak occurs. Due to the rather narrow peak, if you observe at 2100 on 3 January you may see very few if the peak doesn’t occur until 0600. Still, it’s very much worth a look, just in case!

How many Quadrantid meteors will I see?

Where are you observing from?	Limiting magnitude	Number of Quadrantids per hour if peak occurs at 2100	Number of Quadrantids per hour if peak occurs at 0000	Number of Quadrantids per hour if peak occurs at 0300	Number of Quadrantids per hour if peak occurs at 0600
Very light polluted city centre	3	3	5	7	10
Suburban Site	4	5	9	14	20
Rural Site	5	11	18	27	38
Dark Sky Site	6.5	31	50	77	109