Introduction to Celestial Navigation for Mariners

The Marine Sextant, The Sun, and How to Navigate By Lighthouses in the Sky!
Free tutorial
Rating: 4.7 out of 5 (115 ratings)
3,087 students
1hr 54min of on-demand video
English [Auto]

In this free course you will learn about the marine sextant and how to use it to navigate on the ocean.


  • Having a bit of experience on the water is good, but this class is for beginners.


In this course, you will learn about the basics of celestial navigation, including all about sextants and how to use them, as well as the navigational math required in celestial navigation.  Eventually, we move onto pretty advanced topics such as sextant adjustment and using the Moon, Stars, and Planets. 

This course is designed for recreational or professional sailors and power-boaters interested in marine navigation, sailing using primitive navigation techniques, and self-reliance! 

Who this course is for:

  • Sailors, power-boaters, and mariners interested in celestial navigation.


Professional Mariner and Educator
Christopher D. Nolan
  • 4.7 Instructor Rating
  • 652 Reviews
  • 5,289 Students
  • 10 Courses

I have had the pleasure of sailing professionally as a Coast Guard cutter commanding officer and deck watch officer, as well as a civilian tall ship captain.  I love teaching and learning about maritime topics! My formal CV is below:


Practical Navigator Training  2013-Present

Owner and Educator, Nautical Science

Primary curriculum designer and instructor for professional maritime courses from basic captain's licenses to advanced celestial navigation. 

Sea Education Association 2015-Present

Assistant Professor, Nautical Science & Leadership

Ship captain and lecturer in nautical science and leadership for post secondary sail training programs. Programs are a semester in length and combine formal classroom instruction with oceanographic research cruises aboard one of two 150+ ton sail training vessels. In addition to teaching, the captain is responsible for vessel operations, compliance with regulatory bodies such as the U.S. Coast Guard and American Bureau of Shipping, general maintenance, crew training, and voyage planning.


Domestic – Master of self propelled vessels (incl. Aux Sail) upon Ocean Routes, under 1600 GRT.

International (STCW) – Master less than 3000 GT. Advanced firefighting, vessel security officer, radar observer (unlimited), able seaman (unlimited) etc.


Professional Science Master’s Degree: Fisheries & Wildlife Administration 2016

Oregon State University

Joint Professional Military Education, Phase One

United States Naval War College

Bachelor of Science (Honors) – Marine & Environmental Science 2002

United States Coast Guard Academy

Chemical & Physical Oceanography Concentrations



The Cutterman’s Guide to Navigation Problems. 287-page celestial navigation manual. 2013

EAGLE SEAMANSHIP: A Manual for Square Rigger Sailing, 4ed. Naval Institute Press. 2011


Huzzey, Linda M. and Nolan, Christopher D. 2005. Residence Time of Smith Cove, Thames River Estuary, USA. USCG Center for Advanced Studies.

Websites/Asymmetric Learning

The Practical Navigator: a site dedicated to navigation and seamanship.


U.S. Coast Guard Environmental Sustainability Award for Operational Units, 2010. Awarded for making significant contributions to reductions in fuel, water and consumable materials waste while serving as commanding officer (master) of CGC JEFFERSON ISLAND.

U.S. Coast Guard Educational Service Provider of the Year, Afloat Units, 2003. Awarded for dramatically improving off-duty education processes for enlisted personnel while serving as first lieutenant (third mate) of CGC ALEX HALEY.

Various personal and unit awards from U.S. Coast Guard, including four USCG Commendation medals.

RELATED PROFESSIONAL EXPERIENCE (United States Coast Guard Officer):

Cleared to view Top Secret (TS) Information by Single Scope Background Investigation (SSBI). Clearance (S) or (TS) maintained 2001-2015.

Chief, International and Combatant Commander Planning Section 2014-2015

Alameda, CA – Responsible for converting higher policy and strategic direction into operational planning guidance for all international Coast Guard missions in the Pacific theater. Coordinated Department of Defense and International response operations plans for USCG Pacific Area.

Commanding Officer (Master), USCGC JEFFERSON ISLAND 2010-2012

Portland, ME – Complete responsibility for training, budget, well being, and discipline for 110’, $8m ship and 18-member crew. Conducted fisheries law enforcement and search & rescue from Canadian border to New Jersey.

Navigator/Operations Officer (Second Mate), USCGC EAGLE 2008-2010

New London, CT – Coordinated all training, cutter navigation, and public relations for 295’ barque-rigged tall ship. Managed up to 60 crew and 135 trainees and coordinated all port logistics for numerous domestic and foreign port visits.

Joint Rescue Coordination Center Command Duty Officer 2006-2008

Honolulu, HI – Managed all Coast Guard tactical operations and search & rescue response in 12.2 million square mile area of responsibility in central Pacific Ocean.

Commanding Officer (Master), USCGC DORADO 2004-2006

Crescent City, CA – Complete responsibility for training, budget, well being, and discipline for 87’ $5m ship and 12-member crew. Conducted fisheries law enforcement and search & rescue from Puget Sound to San Diego.

First Lieutenant (Third Mate), USCGC ALEX HALEY 2002-2004

Kodiak, AK – Conducted fisheries law enforcement and search & rescue in the Gulf of Alaska and Bering Sea. Supervised 35 personnel and $120k annual operating budget for deck and weapons maintenance & training. Leading fisheries law enforcement boarding officer for ensuring at-sea compliance with commercial fishing and safety regulations.

Top companies trust Udemy

Get your team access to Udemy's top 26,000+ courses