ReedNavigation.com

Classes in celestial navigation and related topics
 

Lunars and Longitude

Winter / Spring 2026:
  • Register Mar 14,15 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:


Homer Smith wrote:
Over the past few years I have taken all of the Celestial Navigation courses taught by Frank Reed at ReedNavigation.com and I recently repeated Modern CN 1 & 2 just for the pure enjoyment that it brought to me.

My interest in CN started a few years ago as I puzzled over how the stars could be used to find one’s position on the earth. I tried to learn CN through self-study, but I couldn’t make the subject matter interesting and realized that this was not the correct approach. You need a skilled instructor that can guide you through the learning process, and that’s what Frank Reed provides.

In a relatively short period of time I had a solid grounding in CN. Frank has unmatched knowledge of CN. His classes are fun, interesting, and sprinkled with historical context and include as much or as little math as you desire. His visual aids were very helpful and the time spent on discussing how to properly use a sextant to take a sight was beneficial. You will learn how to find stars in the night sky by which to navigate. The downloaded course guide is very concise and includes tables that are valid for 5 years into the future.

You don’t need to be at sea to do CN. I live inland and learned in the class how to do land-based navigation with a sextant, either with a large or small body of water to provide a true horizon, or with no water horizon at all.

Going back 250 years, I understand how CN was practiced through the ages, up to the present time with calculator, equations and tables. Thanks to Frank, I take great satisfaction in knowing that I possess a skill that very few people have. I highly recommend his courses.

Homer R. Smith M.D.
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
John Brown wrote:
Frank
Thanks for a great app. The new option of using SI unit is really useful for us on the other side of the pond.
I have upgraded to the pro version and passed news of the upgrade to a friend learning to use her sextant. No doubt she will also relay this info.
Best regards
John Brown

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