Hello everyone!
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A few people have been asking me if it's worth braving the cold tonight to attempt observing the Geminids meteor shower. ?Tonight is the peak, and the sky is expected to be clear around the Ottawa region... although it'll be cold (down to around -15C to -18 plus windchill).
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The Geminids have long been my favourite annual meteor shower. ?It is consistently active every year, produces a lot of bright, colourful meteors that move gracefully through the winter constellations, and under the best observing circumstances, they can reach up to 100 or more meteors per hour! ?The Geminids are also visible all night. ?For the Ottawa region, the radiant is low at 6 pm (local time), so only low rates can be expected. ?By 10 p.m., the radiant near the bright star Castor is 40 degrees high, and already plenty of Geminids can be seen. ?The radiant reaches its highest point in the sky at 2 am, and Geminids will appear to drop down in all parts of the sky.
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Unfortunately, this year's Geminids will be severely hampered by a nearly Full Moon. ?Only the brighter meteors will be visible. ?
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On the plus side, the weather forecast for tonight looks excellent (but cold).
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During the 2022 Geminids, a 74% gibbous moon was up for most of the night and reduced significantly the sky darkness during the optimal viewing times (that is when the radiant is high up near the peak of the shower). ?Despite the Moon's presence, I went to a dark sky site east of Ottawa. ?I was fortunate to have good sky transparency — free of any clouds, humidity or haze. ?I could see stars as faint as 5.4 (normally can see up to 6.2 from the same location on moonless nights). ?It was also quite cold with the wind. ?Was it worth it? ?OH YES! ?During the best observing hours, I had visual rates of 48, 52 and 62 Geminids per hour! ?Sometimes, I would see 2 or 3 meteors within a few seconds, and a few minutes of inactivity. ?But I was impressed at seeing so many meteors with a bright moon in the sky. ?In 4.5 hours of actual viewing time, from midnight onwards, I counted 287 meteors — exceeding my expectations! ?I'm not so sure that I would expect to see as many meteors tonight as the Moon will be even brighter.?
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Tonight, the Moon will no doubt reduce significantly the display and wash out most Geminids. ?The fainter meteors will be invisible. ?In my opinion, a good proportion of Geminids are bright enough to punch through the moonlight! ?It really helps to have a good open view of the sky, away from trees, buildings or other obstructions. ?Rural sites will also have an advantage by having less artificial light pollution — therefore, less total light pollution to contend with.
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According to the IMO, the nominal peak time of the 2024 Geminids is predicted at 01h UT (which translate to around 8 p.m. EST) on the evening of December 13 (tonight!). ?The peak is quite broad, and can last several hours, followed by a sharp drop in rates. ?During the early evening, the radiant will be a little low, and the Moon will be very high and hard to avoid. ?It might be a better strategy to wait until 10 or 11pm, for the radiant to be much higher. ?Facing the north or east and looking a little lower will keep some of the moon's glare behind you. ?If you look towards the north around 11pm, any Geminids will appear to drop down towards the horizon. ?Geminids that appear further away from the radiant also tend to have longer paths. ?These can be easier to spot than the short Geminids near the radiant.
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One more strategy is to skip the first half of the night, and get up to watch during the last hour or two before dawn (say 4 a.m. onwards). ?The moon will still be up but much lower over the western horizon. ?For instance, the Moon will be only 17 degrees above the western horizon at 5 a.m. ?It will then be easier to avoid its glare. ?There is also a possibility that the Geminids could switch to brighter meteors and fireballs late tonight as the Earth starts to exit the stream (an effect known as "mass sorting").
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In a nutshell, the Geminids are considered to be the best annual shower, along the Perseids and sometimes the Quadrantids. ?The Moon will greatly reduce their visibility tonight, but try to observe them anytime after 10 p.m., and you might be rewarded by some nice meteors.?
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If you succeed in observing or photographing Geminid meteor shower, I would love to see your reports : )
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Here's some more info about the observing the 2024 Geminids:
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Clear skies and stay warm!
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- Pierre ?
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yeldahtron