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John Wakefield wrote in his poem, Seafarer, “All I ask is a tall ship and a star to steer it by.”
Navigation is the art and science of safely directing the movement of a vessel from one point to another. To do this, navigators need to know the exact location of the ship.
A traditional method for Sailors aboard the aircraft carrier USS Dwight D. Eisenhower (CVN 69) to determine the exact location of the ship is by celestial navigation.
Celestial navigation is a method of fixing a point on the earth’s latitudinal and longitudinal lines, which identifies an estimate location within a 30 to 50 nautical mile radius, but a skill quartermaster can get a fix within one nautical mile.
“There was a brief period between 2006 and 2015, when the Navy turned to Voyage Management System (VMS), an electronic program which uses GPS technology,” said Senior Chief Quartermaster Michael Ferrara, Ike’s senior Quartermaster.
GPS is still the predominant method used on Ike, which gives a more exact location, but is also vulnerable to being denied or spoofed.
Celestial navigation is now used as a contingency in open ocean if both GPS and Inertial Navigation System are compromised. The Navy determined it’s a necessary skill for the quartermaster of the watch (QMOW). To maintain that required knowledge, it’s practiced every day on Ike.
Celestial Navigation was reestablished in 2015 at enlisted QM A-school and Surface Warfare School (SWOS) for surface warfare officers and senior navigators. Ferrara attended a five week course at SWOS as a prerequisite to becoming a senior navigator.
“One of the cool things from SWOS school is that you go to a planetarium and that’s where they display stars on the ceiling to explain the celestial sphere and how to apply the math from various navigation publications.”
He began his practice in 1999 aboard the Spruance class destroyer USS Peterson (DD 969) before electronic charts were used to identify the ship’s location. Now he’s applying his knowledge to training Ike’s navigation team. The quartermaster of the watch (QMOW) now uses System to Estimate Latitude and Longitude (STELLA).
“With some general information, like the date and which hemisphere the ship is in, STELLA can generate an astronomical map of the sky and then also do the calculations for the exact location with the QMOW’s fixes,” said Ferrara. “The process of using the sextant to gather the fixes is the same as it always has been.”
One hour before sunrise and one hour after sunset, celestial measurements are taken when the stars and the horizon can both be seen.
“My first fix was 40 nautical miles away from being exact,” said Quartermaster 3rd Class Daisy Nunezlopez, who frequently stands QMOW. “For knowing where we are in the open ocean, that’s not bad. Now I can get it within 10 nautical miles.”
The measurement is taken by using the sextant to determine the angle between a star and the horizon. When done for three stars, it’s possible to plot the ship in the middle of this triangle. The calculations also adjust for the earth’s curvature and other factors, which are identified in the publications such as the Nautical Almanac.
Not all of celestial navigation is determining the ship’s location. A Day’s Work in Navigation, another instruction used for reference, outlines the QMOW’s tasks that need to be done throughout the day. It includes sunrise amplitude, local apparent noon, calculating the gyro (the compass) error as well as celestial navigation.
Ferrara said that he’s starting the quartermasters off by doing calculations by hand for sunrise and sunset vice relying on STELLA.
“Senior Chief wants to get us to where we are able to know where we are celestially, not just by using a computer,” said Nunezlopez. “There’s something mystical and transcendent about it. It’s cool to see the same patterns again and again, and witness a little bit of the mysteries of the cosmos.”
Celestial navigation is a source of pride within the quartermaster community. Nunezlopez decorated the navigation door with a celestial painting and it’s common for quartermasters to have things that depict it like shirts and belt buckles.
“I have a small leather bound journal with a couple of decades of my own celestial navigation. The art and science dates back to Nathaniel Bowditch and Magellan,” said Ferrara. “I record the name of the star and how near my fix was to the ship’s actual position. Using a sextant to calculate our position is something Sailors did on clippers many years ago. I like to think I’m keeping that spirit alive in an age of stealthy warships and electronic navigation.”
| Date Taken: | 03.31.2020 |
| Date Posted: | 05.11.2020 02:56 |
| Story ID: | 369671 |
| Location: | ARABIAN SEA |
| Web Views: | 98 |
| Downloads: | 0 |
This work, Written in the Stars, by SN Ashley Lowe, identified by DVIDS, must comply with the restrictions shown on https://www.dvidshub.net/about/copyright.
