The night of May 23/24 could go down in astronomical history for the first appearance of the Camelopardalids, a new meteor shower spawned by the periodic comet 209P/LINEAR, discovered ten years ago and languishing in obscurity up until now.

 
That's all about to change as the Earth is forecast to enter the densest part of the trail of dust shed by the comet in centuries past in the course of its 5.1-year obit around the Sun. The minute dust particles burn up in the Earth’s upper atmosphere producing the wonderful spectacle of 'shooting stars'. If that wasn't enough the comet will pass very close to the Earth on 29 May, the miss distance just 8,227,883 kilometres (about 5 million miles) or 0.055 astronomical units, making this cometary close-approach the eight nearest pass known.

US observers in prime position

Astronomers had predicted a possible 'storm' of shooting stars with over a 1,000 meteors an hour bursting into life, which would be a great sight even from moderately light-polluted areas. Some astronomers still cling to this view but most now think we could see 100 to 400 meteors per hour from dark sky locations. Meteor showers like the Perseids have activity spread over several weeks with a sharp, distinct peak where the most intense activity is seen.

The Camelopardalids are predicted to peak between 06h to 08h UT on 24 May, three hours after sunset from the UK but prime time early morning slots across North America, with east coast observers favoured around 3am and Californians needing ready around midnight to 1am. The meteors should persist for at least a couple of hours, so for UK observers it will mean rising early for a pre-dawn session with the hope of catching the start of the activity. In fact it might be a better idea to observe as soon as darkness falls as the uncertainty as to what level of activity there's likely to be and when it will happen is marked.

Where to look

The meteor radiant, the point in the sky where if you trace back the apparent path the meteors take against the background stars they all appear to emanate from, lies at RA 08h 11m, DEC +79o, placing it in the constellation Camelopardalis, the Giraffe, about 12 degrees east of Polaris, the Pole Star. Camelopardalis is circumpolar (never setting) from the UK and most of North America and the radiant will be up all night. More good news is that moonlight won't have any impact as the Moon is a waning crescent that doesn't rise until 2.30am BST from London and 3am EDT from New York and lies over 90 degrees from the radiant. Check out the Fluxtimator to see what might occur at your location.

Fast moving comet

So what of the comet? Latest estimates have it around magnitude +13.5 and sporting a short tail in images. It's well placed for UK observers in western Ursa Major, 50 degrees above the western horizon at 11pm BST.

 
Moving south, 209P enters Leo Minor on 22 May and Leo on 25 May, when it could be as bright as 12th magnitude and starting to really motor against the background stars (quarter of a degree an hour) as it homes in on its date with Earth.

From now it steams along, rocketing southwards at 10 degrees per day as it becomes a very difficult object by the evening of 27/28 May, embedded in the gathering twilight among the stars of Sextans.

USA prospects

Observers in the USA will fare a little better, especially from the southern states, the comet being low in the south-west through close approach and on into the beginning of June. It might reach mag. +10.7 at this time.

This image is the average of five 180-second exposures remotely taken with the PlanetWave 17"+ Paramount ME+STL-6303E robotic unit, part of the Virtual Telescope Project. The telescope tracked 209P/LINEAR, so the stars are trailing. Credit: Gianluca Masi, Ceccano, Italy/Virtual Telescope Project
 
As with all bodies that pass very close to the Earth it's advisable to check the comet's orbital elements if you've imputed them into your planetarium programme and the latest ephemeris at the Minor Planet Center's website.

Comet from the Southern Hemisphere

Observers in Australia, New Zealand can pick the comet up in a few days time an hour or so after local sunset. At the start of June it lies at the zenith from Sydney at 7pm EST, lying on the Hydra/Centaurus/Antlia border. 209P/LINEAR becomes circumpolar from Sydney on moving into Crux on 5 June; current predictions have it passing within a quarter of a degree of alpha Crucis (mag. +0.77) on the evening of 7/8 June.