AMATEUR ASTRONOMY:

GEMINID METEOR SHOWER TONIGHT:

Tonight the annual Geminid meteor shower peaks, with the most likely time of maximum intensity being after midnight. The first quarter Moon will set shortly after midnight so there will be little interference from its light. Gemini itself will be rising in the east at about 9pm. Over the past few years the intensity of this shower has been increasing, and it is likely that it will put on a better show than the summer Perseids .

The Geminid shower was first seen only 150 years ago, and it is thought that they are the only meteor shower whose parent body is an asteroid, 3200 Phaethon, rather than a comet. Under good viewing conditions it might be possible to see 120- 160 meteors per minute. For more on this event see this article from wikipedia or, for the more technically minded see the International Meteor Organization Calender. The Astronomy Calender also has a multi-year listing for important sky events. Don't miss the upcoming lunar eclipse on the 21st, the longest night of the year.

AMATEUR ASTRONOMY:

GEMINID METEOR SHOWER TONIGHT AND TOMORROW NIGHT:

The Geminid meteor shower, which usually peaks each year between December 12th and December 14th, is the most reliable and spectacular of the annual meteor showers even though observation is less comfortable than that of other showers such as the summer Perseids. On the other hand the skies are usually clearer in winter than at other times of the year. This year the predicted peak will occur at 16:45 GMT on December 14th. This is 10:45 here in Winnipeg in the CST zone. Consult the Time and Date.Com website for the equivalent time in your locality. Time and Date also gives the times of Sunrise/sunset and Moonrise/Moonset as well as a weather forecast. This year the Moon will not interfere with viewing as it is a thin waxing crescent that sets at 8:18 pm. The expected peak time will unfortunately occur during daylight, but a large number of meteors are likely to be visible tonight, especially in the early morning hours, or tomorrow night. The Geminids have a rather extended peak so that viewing doesn't depend on getting an exact time. All weather reports, whether from Time and Date, from Environment Canada or from the Clear Dark Sky website, indicate good clear viewing conditions tonight but overcast tomorrow night. The Clear Dark Sky site has a wealth of other useful information as to viewing conditions for a vast number of locations in North America.

The Geminids are a rather recent meteor shower, having first been observed by astronomers R.P. Greg, B.V Marsh and A.C. Twining first observed them. They were observed again in 1863 by A.A. Herschel. It was only during the 1870s that astronomers realized that a new annual shower was underway. The Geminids gradually increased in intensity during the last century. This year there may be as many as 120 meteors visible per hour near the peak period. Intensity will decrease only slightly from 6 to 1o hours on either side of the peak. The intensity increases gradually in the 2 to 3 days prior to the peak and then falls off rapidly. Thus tonight should be a good time for viewing, specially after 2:00 am when Gemini is high in the sky (the number of meteors visible is largest when their radiant approaches the zenith).

The meteors of the Geminids are of medium speed, approaching Earth at about 35 kilometers per second. They are bright and usually white in colour, and are often productive of some spectacular fireballs. Their apparent speed is slow, and they can sometimes been seen to have jagged paths and to seemingly split. They leave few visible trails however. The radiant will come from a point just to the northwest of Castor, the upper star in the constellation (see diagram above). The Geminids are rather unique in that they originate from an earth-crossing asteroid, 3200 Phaeton, unlike other meteor showers which originate from cometary debris. This parent body was discovered as recently as 1983 by S. Green and J.K. Davies, using the Infrared Astronomical Satellite. This year Phaeton will be making its closest approach since 1983, coming within 11 million miles of Earth. There is some dispute about the nature of Phaeton as some believe that it is not an asteroid but rather the burnt-out nucleus of a comet.

So look to the northeast early this evening, and higher in the sky later to find Gemini, and happy frigid viewing. Have a look out for Mars as well. It shines brightly at the right-hand side of Gemini as it merges into Taurus. But more on Gemini and Mars later.

Missing the Geminids:
The sky here in Winnipeg clouded over shortly after sundown. It is now midnight, and it is still totally overcast. Looks like I'll miss the show. The western horizon shows no sign of clearing.I'll be up before the sun is, and maybe I'll catch a few meteors then. In the meantime, many thanks to all who checked into this blog for the timing of the event. Hopefully you have better viewing than we have here in Winnipeg. More on events astronomical in the future. Check into Space.com for updates.
Molly with deep sighs

GEMINID METEOR SHOWER TO BEGIN TOMORROW:
The annual meteor shower in the constellation of Gemini, mentioned previously on this blog, is due to begin tomorrow evening. They will peak on Wednesday night/Thursday morning, at which you may expect to see up to 60 meteors per hour. There will be less interference from moonlight than occurred with the Perseids this year. The Moon will enter its last quarter on Tuesday, and be no more than a fat waning crescent at the time of the peak.
The meteors will appear to radiate from an area about half the size of the Moon near the star of Castor in Gemini. This star will begin to rise in the east-northeast quadrant of the sky at about the time twilight comes to an end. This is the best time to catch a sight of 'Earth-Grazers'. These are meteors with long, bright trails that emanate from a point near to or on the horizon. Gemini will be about 1/3rd of the way up from the horizon by 9:00 PM, and by 2:00 AM it will be at the its zenith. The Geminids are actually fragments of an Earth-crossing asteroid, 3200 Phaeton, rather than the usual cometary debris that spawn most meteor showers. As such they are several times denser than the usual meteoroids and appear to travel slower than usual. This makes for better viewing. Their trails will appear longer as well.