Viewing tips for Geminid meteor shower

If you’re looking for a special way to close out 2023 — and you’re willing to brave chilly weather — then look no further than the night sky.

The annual Geminid meteor shower peaks this week and is considered to be one of the best and most reliable annual cosmic light shows, according to NASA. The Geminids are particularly special because they originate from an asteroid rather than a comet.

Here’s all you need to know about the meteor shower, including when and where to watch it in the Bay Area.

These meteors in the Geminid shower come from the trail of debris left by the asteroid 3200 Phaethon, first discovered in 1983, according to Jon Rees, support astronomer at Lick Observatory near San Jose.

Meteor showers typically occur “when Earth crosses paths with debris left behind by comets,” he said. Thus, the fact that the Geminids are associated with an asteroid “makes them pretty special.”

Comets are made of ice and dirty debris, while asteroids are composed of rock and metal, according to NASA.

“As the asteroid orbits the sun, it will eject dust, pebbles, pieces of the asteroid,” Rees said. “They are typically very small, about the size of a grain of sand, and when Earth crosses paths with this debris it burns up in our atmosphere and leaves behind a nice trail in the night sky.”

Elinor Gates, staff astronomer at Lick Observatory, said that 3200 Phaethon’s trail is “old,” and the meteors “tend to be very bright and quick.”

Meteor showers typically are named after the constellation from which the meteors appear to emanate,

John Sebastian Russo/The Chronicle from our vantage point on Earth. The Geminids appear to radiate from the Gemini constellation and very close to the Castor star, Gates said — hence the name, although the constellation is not the actual source of the meteors.

The meteor shower became active Nov. 19 and runs through Dec. 24. It peaks Wednesday night into the early morning hours of Thursday.

During peak activity and in perfect viewing conditions, up to 120 meteors per hour can be viewed. But Gates said it’s more likely people will see a dozen to 50 meteors an hour.

“The new moon occurs on Dec. 12, so we will have a dark sky to view the meteors,” Rees said. “The radiant will be overhead around 2 a.m., and this is likely when you’ll see the most meteors. But you should get a good view throughout the night.”

The other variable is the weather forecast, especially if skies are cloudy. But so far, viewing conditions in the Bay Area are looking favorable.

According to Chronicle newsroom meteorologist Anthony Edwards, so far the week looks dry, with no rain in the forecast for Wednesday though there could be some passing clouds.

It’s winter, so bundle up and bring blankets, lawn or camping chairs for your Geminids viewing excursion. Find a spot where the sky is very dark, away from city and street lights. This may require driving up a hill or to a more rural area. Many parks close in the evening, so check before you venture out.

“The most important things are a dark sky and a clear, wide view of the sky,” Rees said.

It takes time for your eyes to adjust to the dark, which can take 20-30 minutes, so experts urge patience.

“Look for at least an hour,” Gates said, adding that the moon will not be up during the peak of the meteor shower, which will make for a better watching experience.

No special viewing equipment such as a telescope or binoculars is necessary.

“While the meteors will appear to originate from a point in the constellation Gemini, the meteors will be visible across the sky,” Rees said.

Gates advises going with a group because the meteors can “show up anywhere,” so you’ll have more eyes on the sky.

The annual Geminid meteor shower peaks this week — from late Wednesday to early Thursday, when up to 120 meteors per hour can be viewed.