Brian Emfinger / RealClearWX

Arkansas photographer Brian Emfinger captured this flash of a Geminid fireball over the city lights of Fort Smith, Ark., early Thursday, using a camera that was set up on Mount Magazine, the state's highest point. For more about Emfinger, check out his website, RealClearWX.com.

Arkansas photographer Brian Emfinger says the best meteor he ever captured on camera happened while he was napping.

"Definitely the brightest meteor I've ever imaged," he said today. "If I was awake, it would have been the brightest meteor I've ever seen."

Emfinger, who snaps pictures of storms and sky phenomena for his RealClearWX website, said the Geminid fireball streaked over the skyline of Fort Smith, Ark., at around 1:07 a.m. CT Thursday, while he was in the midst of an all-night meteor photography session.

The Geminid meteor shower is the year's most reliable display of shooting stars, reaching its peak annually on the night of Dec. 13-14. By most accounts, this was a great year for the Geminids, due to a moonless sky and a meteor tally that reportedly peaked at levels well above the typical 100 to 120 per hour. The flashes occur when bits of debris left behind by an extinct comet known as Phaeton burn up in Earth's atmosphere.

Like many meteor fans, Emfinger was watching the skies not only on the peak night, but on the preceding nights as well. On Wednesday night, he drove up to the top of Mount Magazine, the highest point in Arkansas, and then set up a fisheye camera to take pictures automatically. Sometime after midnight, he settled in for a nap in his car.

A while later, he got a call on his cell phone from a friend who reported seeing something like lightning flashes on the horizon ... on a clear night. "He was assuming it was some spectacular meteor," Emfinger recalled.

As soon as he could, Emfinger checked the shots that were stored on his camera. "I scrolled through them real quick — and there it was, descending toward the skyline of Fort Smith," he said. Observers in Oklahoma and other westward states also reported seeing the fireball, Emfinger said.

That blaze of celestial glory wasn't this week's only Geminid highlight. Scroll down below for other scenes from the past couple of nights. It's important to remember that the show isn't over yet: Although the Geminids have passed their peak, there's still a chance to see a fair number of meteors tonight and tomorrow night. Keep a watch on SpaceWeather.com's gallery for still more meteor photos.

One more thing: In advance of the peak, some experts speculated that there might be a separate wave of meteors that would have been known as the Piscids, sparked by the debris left behind by Comet Wirtanen. These meteors would appear to emanate from a point in the constellation Pisces, rather than the Geminids' point of origin in Gemini. However, I've seen no reports of significant sightings on Thursday night — which suggests that the Piscid meteor shower was a no-show.

Brian Emfinger / RealClearWX

Photographer (and storm chaser) Brian Emfinger captured a bright Geminid fireball on camera early today from Mount Magazine State Park in Arkansas. "My camera caught a bunch of meteors, the most I've ever gotten in any one night of shooting meteors," Emfinger told SpaceWeather.com. Check out Emfinger's website, RealClearWX.com.

Frank S. Andreassen / Nettfoto.com

Norwegian photographer Frank S. Andreassen captured this shot of a meteor streaking through the northern lights outside Harstad at 9:30 p.m. local time Thursday night. For more of Andreassen's work, go to Nettfoto.com.

Menahem Kahana / AFP - Getty Images

Israelis float in a hot spring on the shore of the Dead Sea, near the kibbutz of Ein Gedi, as they look for Geminid meteor streaks above the Judean desert.

Jeffrey Phelps

A Geminid meteor appears to dive into the trees in Saukville, Wis., early Friday. Photographer Jeffrey Phelps sent in this image via NBC News' FirstPerson photo-sharing page for sky highlights. (You can, too.)

More about the meteors:

• Aurora sets stage for meteor show
• Flash interactive: What causes a meteor show?
• The scientific story behind meteor showers

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

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Comet Wirtanen streaks across a field of stars, as seen through a telescope at the Pik Terskol Observatory in the Russian Caucasus. The observers were T. Credner, K. Jockers and T. Bonev. Wirtanen left behind a trail of debris that may spark a minor meteor shower this week.

The Geminid meteor shower looks as if it'll put on a great show late Thursday night and early Friday morning, but this year's production might turn out to be a double feature: Experts say a new bunch of shooting stars, tentatively known as the Piscids, might make their appearance as a warmup act.

"If it does appear, it will be a minor shower, so people should not expect a major outburst" said Bill Cooke of NASA's Meteoroid Environment Office at Marshall Space Flight Center in Alabama. "The Geminids will dwarf this new meteor shower. They're still the best show."

The Piscids are expected to produce 30 meteors per hour at most, while the Geminids can account for 100 to 120 meteors per hour, Cooke said. There's also a chance that the Piscids will be a non-event.

The Geminid shower is a completely different kettle of fish: It  ranks as the year's most reliable meteor shows. The Geminids peak annually on Dec. 13-14 when Earth passes through the trail of cosmic debris left behind by a fizzled-out comet known as Phaeton. Because of the orientation of that debris trail, Geminid meteors appear to come from a point in the constellation Gemini — hence the shower's name.

Based on computer models run by Russian forecaster Mikhail Maslov, the new meteor shower would seem to emanate from a different point in the sky, in the constellation Pisces. The source of the cosmic debris would be Comet Wirtanen, which was discovered in 1948 and takes 5.4 years to orbit the sun. NASA says the comet has skirted Earth's orbit many times, but according to Maslov, this year could mark the first time Earth plows right through Wirtanen's debris trail.

"The meteors from this new shower will be slower-moving than the Geminids," Cooke said. Also, the Piscids are expected to peak before the Geminids. Cooke suggests setting up your meteor-watching post early Thursday evening in case the Piscids show up, and then lingering into the wee hours of Friday for the Geminids' main event.

This year should be particularly good for Geminid watchers, because there'll be no moon in the sky to overwhelm the meteor streaks. "We saw a fair number last night," Cooke said. "I expect they will do about normal this year."

Cooke is getting set to host an Internet chat and live video feed of the Geminids from Marshall Space Flight Center on Thursday night, starting at 11 p.m. ET. He's also reminding people to "stay warm" when they go meteor-watching on a frosty December night.

British astronomer Mark Thompson has lots of good advice about what to wear for winter stargazing at Discovery News, and I'll just add that a thermos of hot beverage (coffee or tea, hot chocolate or soup) goes a long way toward keeping you comfortable amid the chill. You'll want to get to a place with clear, open skies, far away from city lights — and don't expect to see a fireworks show. A meteor shower is a far more subtle affair. My top 10 bits of advice for watching August's Perseid meteor shower work surprisingly well for December's Geminids, and EarthSky.org offers yet another top-10 list of tips.

If you snap a great picture during the Geminids, please consider sharing your gem with the rest of us. You can upload photos via our FirstPerson Web page for sky highlights, and I'll try to pass along some good ones on Friday. Keep a watch on SpaceWeather.com as well.

More about meteors:

• Year's best meteor shower nears its peak
• Superb Geminid meteor shower coming up
• Flash interactive: What causes a meteor show?
• The scientific story behind meteor showers

Tip o' the Log to NASA Science News.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.

Jimmy Westlake / Colorado Mountain College

A Geminid meteor streaks across the night sky, with circular star trails whirling the background, in a time-exposure photo made by astronomer Jimmy Westlake in December 1985.

December isn't exactly prime time for sitting out in the cold and dark, but tonight could be the exception: The most productive meteor shower of the year is due to reach its peak tonight. Don't just take it from me -- you can ask the experts yourself during a series of online chats building up to the Geminid meteor shower.

There's lots that's appealing about this year's Geminids: Astronomers say the shooting stars could be spotted at a rate of more than one per minute under peak conditions (the equivalent of 60 to 120 per hour). The moon is in its first-quarter phase, meaning that it'll be setting around midnight and won't be glaring in the sky during the peak viewing hours (midnight to morning twilight). Earth is projected to pass through the thickest part of the meteor debris stream during the wee hours of the morning for North Americans, who are in just about the best position to see the maximum flash.

So what's the problem? Why aren't the Geminids as highly anticipated and well-known as the Perseids of August or the Leonids of November. Well, the biggest drawback is that it's c-c-c-cold out there this time of year. That means it's more important than ever to bundle up, have a comfortable lounge chair and sleeping bag at the ready, and bring along hot beverages to keep warm.

This chart indicates the radiant for the Geminids -- the point in the sky from which the meteors appear to emanate.

The best viewing is available far from the glare of city lights, where you have an unobstructed view of as much of the sky as possible. Geminid meteors are so named because they appear to emanate from a point in the constellation Gemini. But the shooting stars can appear anywhere in the sky, so don't just stare at Gemini. There's no need to gaze through binoculars, though you may want to take them along to see other celestial points of interest.

The early reviews are already streaming in, and it's a strong thumbs-up: Peak rates rose to as high as 40 meteors per hour last night, according to statistics gathered by the International Meteor Organization.

Exactly when and where should you go skywatching tonight? And what will you see? Three online tools can help you sort out those key questions:

• When? NASA's Fluxtimator is a Java-based online application that lets you specify your location, date, viewing conditions and the meteor shower you're interested in -- and then shows you how many meteors you could expect to see. Today, it's telling me that I might spot 80 meteors per hour at 1 a.m. PT if I'm in the countryside around the Seattle area. That's assuming that the skies are clear.
• Where? The Clear Sky Chart is a fantastic database that gathers up weather data for skywatching hot spots in the United States, Canada and parts of Mexico, and translates all those readings into graphical charts showing you what to expect at a particular location, hour by hour. You can get a quick read on whether it's likely to be cloudy or clear, what the atmospheric "seeing" conditions will be, and when dawn is due to start breaking. I can see already that the forecast is not that great for my favorite viewing spot, Rattlesnake Lake in the Cascade foothills.
• What's it all about? NASA's Marshall Space Flight Center has set up an online chat about the Geminids with meteor experts Danielle Moser and Rhiannon Blaauw. They can provide a preview of the event, advice for skywatching, and the science behind the meteor phenomenon. The main event starts at 11 p.m. ET, when NASA astronomer Bill Cooke presides over a late-night meteor chat. That's due to last until 5 a.m. ET.

One of the big mysteries surrounding the Geminids has to do with their origin. Annual meteor showers like the Perseids and Leonids are generally fueled by the gritty debris left behind by a comet that just happened to cross Earth's orbit. When those bits of rock hit the upper atmosphere at a speed of 22 miles per second, air friction causes them to vaporize -- leaving behind the glowing streaks we associate with shooting stars.

The weird thing about the Geminids is that it's thought to be caused by debris from an orbit-crossing asteroid rather than a comet. The asteroid Phaeton, to be precise. Astronomers have come around to the view that Phaeton may have started out as a classic comet but eventually lost its ice, leaving the rocky core we see today. The leading hypothesis is that Phaeton's rock becomes fractured due to thermal stresses when it passes close to the sun, and leaves behind fresh trails of debris during each orbit. But there are some things about that hypothesis that don't quite add up.

"The Geminids are my favorite, because they defy explanation," Cooke observed in a NASA preview that explains the mystery more fully.

For general advice about maximizing your viewing experience, review my top 10 meteor-watching tips from August. And if you miss tonight's show due to weather or holiday-season weariness, never fear: The Geminids are expected to provide encore performances through the next few nights. Then it'll be only a few more days until the next celestial extravaganza: the total lunar eclipse on Dec. 20-21.

Update for 1:10 p.m. ET: The MeteorWatch.org website is keeping track of meteor sightings around the world. To share your shooting-star reports via Twitter, just include the term #meteorwatch and your location in your tweet. That way they'll show up on this Meteor Map.

Update for 3 p.m. ET: NASA is using a Java-based client for the Geminids chat, so you'll have to have Java enabled in order to participate. The chatsters are getting lots of great questions, and I expect it will be the same tonight when Cooke is on the show. Starting this afternoon, you should be able to watch live video from Marshall Space Flight Center's "meteor-cam," via the same Web page used for the chat.

Got a celestial sighting to report? Share your skywatching experiences as a comment below. You can also connect with the Cosmic Log community by "liking" the log's Facebook page or following @b0yle on Twitter.