ReedNavigation.com

Classes in celestial navigation and related topics
 

Lunars and Longitude

Winter / Spring 2026:
  • Register Mar 7,8 ATLANTIC session: 10am-4pm US Eastern time (1500-2100 UT), online.
  • Register May 11,12,13 PACIFIC session: 8pm-11:45pm US Eastern time (0100-0445 UT next calendar day), online.

Learn the art of Lunars, the famous celestial navigation method of finding longitude by observing the Moon in this intermediate-level workshop. Taught by Frank Reed, the world's leading expert on the history, science, math and practice of lunars. We cover practical application of the method as well as its extraordinary history, including primary-source evidence in the logbooks of the museum's collections. We will follow an extraordinary voyage in the 19th century, a Boston trading ship on a quest for coffee, sailing to India and home, all thanks to Lunars. And we'll follow William Bligh and the "Bounty" to Tahiti and the famous mutiny that followed, relying on the Moon for their successful navigation.

Lunars were widely used at sea in the early 19th century in the era before chronometers became common. Lunars made global navigation possible. Observing with a fine sextant, navigators used the Moon as a great natural clock in the sky. From James Cook and Nathaniel Bowditch to Joshua Slocum, lunars were a challenge that proved a navigator's skill.

Participants in this workshop will learn the fine details of adjusting a sextant properly for shooting lunars, tricks for taking accurate sights today, and easy methods for working with these infamously difficult observations both by modern and historical means. We'll also talk about some of the interesting mathematics and astronomical discoveries that made lunars possible. For a modern celestial navigator or navigation enthusiast, there is no better test of your sextant and observing skills. Weather permitting, we will have opportunities to take actual lunar observations.

All workshops: $ 149 per person, per workshop

Created and taught by Frank Reed, celestial navigation and astronomy consultant on the team that found Shackleton's "Endurance" in 2022. Also a recent guest expert in celestial navigation on Neil deGrasse Tyson's StarTalk on The National Geographic Channel.

If you're registered for an online workshop, you're invited to attend hour-long sextant practical sessions in Rhode Island and Connecticut scheduled as weather and other factors permit. These live, in-person sessions are included in your registration for online classes.

Comments:


Captain Richard D. Buchanan wrote:
I have taken Frank's Modern Celestial Navigation class twice. I am always inspired and I always come away with a few practical techniques and more than a few insights into the history and beauty of celestial navigation. You owe it to yourself to enjoy this class, whether or not you are a mariner.
Philip M. Sadler wrote:
What a joyful and stimulating experience to enroll in Frank Reed's class, Celestial Navigation: 19th Century Methods. Frank is a skillful and engaging teacher, able to draw students into this fascinating subject, whether they be novice or experienced. His depth of knowledge is tremendous. Participants get a real taste of what it was like to be aboard a sailing ship of the day. I learned much to enliven my own teaching and decode 19th century ship's logs. It is a rare experience, indeed, to have so much thoughtfulness, enthusiasm, and fun packed into two days. This is the way to learn!

Philip M. Sadler, Ed.D.
F.W. Wright Senior Lecturer in Celestial Navigation
Harvard University Astronomy Department
Cambridge, MA
Doug MacPherson wrote:
I recently took online versions of Frank Reed's "Celestial Navigation in the Age of Sail", and "Lunars - Finding Longitude by Lunar Distances". I couldn't have been more happy with them. Having originally learned post WWII celestial methods as an officer in the United States Navy, and taken it up as a hobby, I was quite familiar with that era's procedures. However, I was intrigued by how they managed prior to then. Frank's two classes filled that void. His vast knowledge of the subject, both the technical aspects of the work as well as the historical significance were perfectly balanced. These are classes that can be thoroughly enjoyed by both the novice as well as the well versed practitioner. Recipe's for doing the work, the science behind those recipes, and actual voyages by the sailors that practiced the art were all presented with wonderful clarity. If "time sights", "cleared lunar distances" or "apparent time" have ever roused an interest, you owe it to yourself to take one of Frank's classes.

Doug MacPherson
Lieutenant, USN sep.

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