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Daily Updates: August 2001
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 Daily Updates: September 2001
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sunny weather

69°F (20.6°C)
Latitude: 00 deg 5.2'N
Longitude: 91 deg 48’W
Wind Direction: SSW
Wind Speed: 14 Knots
Sea State 3
Swell(s) Height: 2-4 Foot
Sea Temperature: 63°F (17.2°C)
Barometric Pressure: 1012.0 MB
Visibility: 12 Nautical Miles

what's to eat today?

Fresh fruits
Banana nut muffins
Steak and eggs
Bacon, ham and sausage
(Dried cereal is always available in the pantry)
OJ in a bucket

Fresh salad
Philly cheese-steak
Cream of mushroom soup
French fries
Ice cream sandwiches

Fresh salad
Chicken Kum Po
Fried rice
Egg rolls
Stir-fried vegetables
Fresh bread
Blueberry Pie

Celestial Navigation
September 3, 2001
by Joseph Ferris and Christina Reed

At sunrise, during the day or at dusk, when the division between sea and sky is a distinct horizon, the Captain and Mates of RV Revelle practice the traditional mariners’ art of celestial navigation.

Standing outside of the bridge, away from their electronic radar and Global Position System (GPS) they hold up the ship’s sextant, a tool that measures the angle of the Sun, Moon, planets or stars from the horizon. These celestial bodies help determine our ship’s position at sea and can check the accuracy of our compasses.

“If you look at three different stars and measure their distance from the horizon, there is only one place in the world where all the angles intersect,” says Eric Wakeman, the Chief Mate. “And that's right where you’re at.”

During the day, as the sun passes overhead, the Mates can also use the sextant to measure different angles of the sun above the horizon. If they also know the accurate time, these angles allow them to calculate their position.

“When we are not busy with dredging or other station operations, we take pride in being able to do celestial navigation and get an accurate fix,” says Captain Chris Curl.

Tonight, with blue whales feeding on krill and Fernandina swallowing much of the southwestern horizon we took a reading off of three stars: Arcturus, Spica and Dubhe, which is the last star on the ladle of the Big Dipper. Sure enough, the position we calculated from those sightings matched where 3 satellites in the GPS constellation have us plotted.


Learn More About...
Global Positioning Satellites and Navigation


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