Northumberland Public Library Presents Fall 2016 Celestial Navigation Class

celestial navigation

The Northumberland Public Library is offering a class in Celestial Navigation for six Monday afternoons from 2 p.m. – 4 p.m., starting September 19 and continuing through October 24. Instructor Jim Schmalz completed the American Sailing Association’s course in Celestial Navigation, ASA107, in 2005, in preparation for a 2006 family sailing trip from Barcelona Spain to Mikonos Island Greece and back.

“Celestial Navigation is making a comeback,” said Schmalz. “After fifteen years out of its syllabus, the US Naval Academy at Annapolis re-instituted instructions in Celestial in September 2015, as fears of possible jamming of GPS signals became more realistic.”

He says celestial navigation is to GPS what camping is to the hotel. Just as there is high-end camping equipment, a sextant can range from a simple plastic $35 dollar version to a precision instrument at $600 or more.

Schmalz will present the Marcq Saint Hilaire, or Intercept, Method, which uses a sextant, an accurate wristwatch, a 2017 Nautical Almanac, a book of solutions called Sight Reduction Tables, the usual plotting implements—dividers and parallel rule. Students will not be required to own a sextant for the class, but those who do buy one will need a little practice to determine a vessel’s position out of sight of land.

“Well, perhaps more than a little practice is required,” said Mr. Schmalz. “I take my sextant along on any boating expedition more than three miles from shore. That’s the distance you need to get a good horizon at sea. I also have an ‘Artificial Horizon’ I can use at home.”

The course may also be of interest to homeschooled, high school-age students as it uses astronomy, physics and math. Schmalz will cover techniques for obtaining observations of the sun, the moon, the four naked-eye planets, and the 30 bright stars used for Celestial Navigation in the Northern Hemisphere using one. The class will include field time for demonstration and practice.

In addition to the Intercept Method, the course will include: Obtaining latitude from noon observations of the sun, and from dawn and dusk observations of Polaris, the North Star; maintaining a DR Plot; how to plan a dawn or dusk observation session; how to obtain running fixes from a single body; and the astronomical background required to better understand the discipline.

“Some math is required, but only elementary-school math: we only add, subtract, multiply, and divide,” said Mr. Schmalz. “You might want to ask your teen to explain sines and cosines, but we don’t actually use them. Someone else has already solved those problems.”

Cost of the course is $5, to cover initial supplies and refreshments. Prospective students may pre-register at by calling the library at 580-5051 or email: You may also register the day the class starts. Call Jim Schmalz at 804-724-9180 with questions or for additional information.


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