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Astrophysicist Hakeem M. Oluseyi has been to dark sky parks and observatories all over the world, but some of the best stargazing he's done has been in the middle of the ocean.
As long as cruise ships are mindful of their light pollution, he said, they can be a great way to stargaze.
In the past, Oluseyi partnered with Princess Cruises and Discovery to bring stargazing programs on board the ships. He's seen some spectacular sights on cruises, including the northern lights and other galaxies.
Here are Oluseyi's tips for the best stargazing on cruise lines, including seeing eclipses, galaxies, the northern lights, and meteor showers on your next cruise.
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Oluseyi has been on five cruises in various parts of the world. "The most amazing one was a trip to Norway on a cruise called Chasing the Northern Lights," he said. That's when he saw the aurora borealis, aka the northern lights, for the first time.
"There are certain astronomical phenomena that sort of just brings the universe to your doorstep, and the northern lights, for me, was like that," he said.
The northern lights are only visible at night. To make sure you don't miss them, you can see if your cruise offers wake-up calls when the lights appear. Many cruises do.
Moreover, location and timing are important. The northern lights are visible most often in northern latitudes including Canada, Alaska, and northern Scandinavia.
You likely won't see them year-round, however. The fall and spring equinoxes are the best time for viewing the northern lights, NOAA notes.
Winter can also be a good time, according to a Viking Cruises representative who told BI over email that daylight only lasts a few hours north of Scandinavia during winter time, offering more opportunities to see this spectacular light show.
Some parts of the world have better skies for stargazing than others.
In particular, "the Canary Islands and Chile are some of the best places to stargaze on the globe," Paul Grigsby, Holland Cruise's vice president of revenue planning and deployment, told Business Insider via email.
Both destinations have cultivated reputations as astrotourism sites and have areas that are dark sky reserves. Plus, Chile's latitude puts it right under the Milky Way.
If you don't mind chillier weather, remote destinations like the Arctic and Greenland also take passengers far from cities' light pollution. Keep in mind, though, that the sun sets late during the Arctic summer, so nights are short.
You might also want to time your trip with a meteor shower, like the Perseids in August. The nice thing about that is that you should be able to see the celestial show from almost anywhere, Oluseyi said.
Though, if epic stargazing is your goal, you should try to avoid areas with notoriously cloudy weather. "I'm not going to cruises in Seattle or London," Oluseyi said.
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Cruise lines are already gearing up for eclipses in 2026 and 2027.
The 2026 eclipse will be visible in Greenland, Iceland, Spain, Russia, and part of Portugal, according to NASA.
Holland America, Cunard, and Princess are just a few of the cruise lines planning trips near some of these destinations for the 2026 eclipse.
For the 2027 eclipse, Egypt's pyramids will have a spectacular view and Viking is planning a Nile River cruise.
Oluseyi chased eclipses for a decade and said you need to be in the right place and have clear weather. The weather can turn quickly "because of the temperature drop that accompanies the moon shadow," he said.
Being on a boat may offer some flexibility. "The deck team can make decisions to reposition based on weather and visibility reports and will do all they can to ensure guests see these events," Grigsby said.
For those who live in the Northern Hemisphere, crossing the equator offers some new views of the sky.
"What's really dramatic about the Southern Hemisphere is the galactic sky that you don't really get in the Northern Hemisphere," Oluseyi said.
In the Southern Hemisphere, the star-packed center of the galaxy, the galactic bulge, is directly overhead.
There are also two satellite galaxies — the Large and Small Magellanic Clouds. The first time he saw them, Oluseyi said he couldn't stop staring. They're "so dang big, bright, and ever-present," he said.
Royal Caribbean, Norwegian, and Viking all offer cruises to Australia and New Zealand, southern Africa, and South America. You can see the Large and Small Magellanic Clouds year-round but keep in mind that the best southern hemisphere stargazing occurs in March through September when the sky is dark for longer.
You can also get a better view of objects in the night sky during a new moon when there's no moonlight to drown them out.
Cruise ships can have their own light pollution, which significantly diminishes how well you can see the stars. "The lights can be so bright that you can't really see the dimmer objects, and most of the cool stuff is dim," Oluseyi said.
When the lights are down, the unobstructed view can be spectacular. "I have been literally all over the world to dark sky locations," Oluseyi said, "but, man, being out in the middle of the ocean — and when they turn off the deck lights — it is one of the best."
Some ships turn off their deck lights so passengers can see the skies better. You may want to inquire before you book about the cruise line's policies on this practice.
Viking's rep said the cruise line's special bird-safe lighting mode helps keep birds from flying into windows but also allows passengers to see stars.
If your ship is dark enough, you might still want some help seeing the stars. You can probably leave your telescope at home. The waves make it too unstable to view objects well. However, wide-field binoculars will let you see more than your naked eye, Oluseyi said.
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Once it's dark, you want it to stay dark. "Eye adjustment is a very precious thing," Oluseyi said. It takes 30 minutes for your eyes to acclimate to the darkness, according to The BBC.
Avoid peeking at your bright phone screen because once that light hits your eyeballs, they'll have to readjust again.
You can also use your phone's settings to apply a red filter, which will help your eyes stay adjusted to the night sky.
You'll want to prepare to be outside for a while.
"It can get cold at night," Oluseyi said. His advice for stargazing from an observatory is to dress warmly and bring snacks. But it applies anywhere. You'll want to stay comfortable and awake so you don't miss the view.
"You'll find yourself freezing," he said. "You'll find yourself sleepy, but it's so worth it."