Image Credit & Copyright: Wally Pacholka of a 2011 Geminid.
Basics: The night of Wednesday, December 13 and the morning of Thursday, December 14, 2017 the annual Geminids meteor shower will reach its peak. As with all meteor showers there’s an estimated viewing window or, “active dates” which in this case runs the middle weeks in December. Peak viewing however is usually narrowed down to a few days or even a single night through the following morning.
This year’s peak hourly rates will reach upwards of 100 per hour and you will want to be looking in the general direction of Gemini in the north. This is a worldwide show and this year that big floodlight in the night sky (the Moon) will still be in its waxing crescent phase so it will have no impact at all. My “Just the Facts” section is below if you don’t feel like reading the whole thing.
Moonlight: For each meteor shower, I offer a Moonlight impact rating from NULL to MODERATE and MAXIMUM based on its age, phase, illumination and rise-set times. New through 1st quarter phases rarely causes any trouble as these young phases set fairly early. Full through last quarter phases are what really cause the heartache as they are up most of the night and or rise late, impairing those peak pre-dawn viewing times. Of course, none of this matters if it’s cloudy so check the weather.
Quick Moon Reference: First Quarter Moon; rises around noon which means it’s already up and overhead at sunset and sets around midnight. Full Moon; rises in the east roughly around sunset, is up all night (usually highest around midnight) and sets at sunrise. Third (last) Quarter Moon; rises around midnight, is high overhead around sunrise and sets around noon.
Notes and Information:
How many meteors will I see?: It’s important to keep in mind that meteor shower predictions are just that; predictions based on past totals so just because it says “X” per-hour you have to understand that predicting these things are about as accurate as weather prediction. Also, when you see “X” per-hour, that rate is assuming that you have an open 360 degree view, at a dark sky location, on a clear night and with the radiant point directly overhead. That being said, your totals (like mine) will probably be half of what’s predicted if you’re viewing from your back yard and you’re within 30 minutes or so of a medium sized city and you can probably half that again if the Moon is up and larger than a small, few day-young or old-crescent.
When’s the best time to look?: Peak viewing is typically a given night as well as the following morning with emphasis on the following morning being the absolute best time to watch. In fact, the closer to morning you can get without twilight creeping in the better; here’s why. If you were to view the solar system from the “top” or “above,” you’ll quickly notice that the planets orbit the Sun in a counter clockwise motion and most also rotate in a counter clockwise motion as well, Earth included (Venus and Uranus are the exceptions). That means just before sunrise, Earth is pointed in the direction of travel in its orbit and meteors are mere bugs or snowflakes hitting the windshield of Spaceship Earth.
Where should I look?: You will want to look in the direction of what’s called the “radiant point” of the shower for best results. The radiant point is where it appears that the meteors radiate from; which is usually associated with the constellation they are named after. For example; the radiant point for the Orionids will be the constellation of Orion. Also the higher that the radiant point gets the better observing may become because meteors radiate out in all directions and most aren’t readily visible until they’re approximately 30 degrees or so from their radiant point.
What do I need?: As for seeing them, nothing. The most important things you need are a clear, dark sky, preferably with a nice wide open horizon and no Moon. In fact you really can’t use tools like binoculars or telescopes for meteor showers because the streak is too long and you simply won’t be able to move your equipment into position in the less than a breath that the meteor streak lasts.
Considerations: are weather and subsequently how you plan to dress for that weather. Red flashlights will help save your eyes because dark adaptation is a key in picking out the faint streaks you won’t be able to see after you just check your cell phone. Besides that, good people, chair, blankets, bug spray, food and try not to lie on any ant hills.
Just the Facts:
Active Dates: December.
Peak Viewing: The night of Wednesday, December 13 through the morning of Thursday, December 14.
Hourly Rates: Upwards of 100 an hour.
Radiant Point: North in the general direction of the constellation Gemini.
Moon Impact = Null! The Moon will be in its waxing crescent phase at only 20% illuminated it won’t rise until after midnight and even then won’t pose much of an issue.
Velocity: 22 mi/sec.
Parent Body: Asteroid 3200 Phaethon. This and the Quadrantids are the only two major meteor showers that don’t originate from a comet.
Hemisphere Favored: Entire Earth.
Time and Date page for this event: https://www.timeanddate.com/astronomy/meteor-shower/geminids.html
Dominic Ford’s “In The Sky” page for this event: https://in-the-sky.org/news.php?id=20171214_10_100