Editor’s note: We’re revisiting this series on navigating by the sun, moon, planets and stars in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it is also a skill that ocean voyagers should have in their toolkit. In this series, we’ll cover all the basic knowledge you’ll require to get up to speed on this elegant and rewarding technique for finding your way at sea. Click to read Part 1, Part 2, Part 3, Part 4, Part 5, Part 6 and Part 7. In this installment, we’ll cover running fixes and the hierarchy of positions from dead reckoning position to multiple simultaneous lines of position fixes. In the previous installment of the series, we looked at how the HO 249 sight reduction…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, planets and stars in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it is also a skill that ocean voyagers should have in their toolkit. In this series, we’ll cover all the basic knowledge you’ll require to get up to speed on this elegant and rewarding technique for finding your way at sea. Click to read Part 1, Part 2, Part 3, Part 4, Part 5 and Part 6. In this installment, we’ll cover the HO 249 sight reduction tables and how to plot a line of position (LOP). The left diagram shows the sun in the morning when it would have a bearing east of south. In that case, Zn =…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, planets and stars in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it is also a skill that ocean voyagers should have in their toolkit. In this series, we’ll cover all the basic knowledge you’ll require to get up to speed on this elegant and rewarding technique for finding your way at sea. Click to read Part 1, Part 2, Part 3, Part 4 and Part 5. In this installment, we’ll cover time, time zones and the Nautical Almanac. Each time zone has a standard meridian. These occur every 15° from the Greenwich meridian at 0°; 7.5° from the standard meridian on either side is the boundary between that…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, planets and stars in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it is also a skill that ocean voyagers should have in their toolkit. In this series, we’ll cover all the basic knowledge you’ll require to get up to speed on this elegant and rewarding technique for finding your way at sea. Click to read Part 1, Part 2, Part 3 and Part 4. In this installment, we’ll cover sextants and sight taking, and the corrections you’ll need to apply to your sight. So far in this series, we have discussed a variety of terms and concepts, but we haven’t talked much about either the process of…
Celestial Navigation: A Practical Guide to Knowing Where You Are by David Berson Seahorse Publishing This short book — only 133 pages — delivers just enough information for the reasonably competent coastal navigator to become a reasonably competent celestial navigator. Berson’s folksy writing style, which readers of these pages have come to appreciate over the past two decades from his regular Nav Problem and from his seminars with the Ocean Navigator School of Seamanship, renders the material not only understandable but enjoyable as well. In fact, I recently read the book from cover to cover on a flight, pausing only long enough to look out the window at the horizon or the blue dome of sky to contemplate the angles, as if comparing my own position in lat/long relative to…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, planets and stars in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it is also a skill that ocean voyagers should have in their toolkit. In this series, we’ll cover all the basic knowledge you’ll require to get up to speed on this elegant and rewarding technique for finding your way at sea. Click to read Part 1, Part 2 and Part 3. In this installment, we’ll cover Local Hour Angle (LHA), and determining assumed longitude and assumed latitude. We’ll also look at the spherical trigonometric process for doing sight reduction. In part three of this series on celestial navigation, we discussed the celestial sphere, the navigational triangle, Greenwich…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, stars and planets in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it’s also a skill that ocean voyagers should have in their toolkit. During the next few issues, we’ll cover all the basic knowledge you’ll need to get up to speed on this elegant and rewarding technique for finding your way at sea. Click for Part 1 and Part 2. To the left, the North Pole is pointed away from the sun (our winter) and the sun’s declination is south. As the Earth continues its course around the sun, the sun heads north until the spring equinox where the sun is on the equator. By the summer solstice,…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, stars and planets in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it’s also a skill that ocean voyagers should have in their toolkit. During the next few issues, we’ll cover all the basic knowledge you’ll need to get up to speed on this rewarding nav technique. In this installment, we’ll discuss how to make our own chart for plotting our celestial navigation data at sea, and we’ll review dead reckoning, plotting, current vectors and compensating for current. In part one, we ended with a discussion of the types of chart projections and why the Mercator-type chart — with the lines of longitude being parallel to each other —…
Editor’s note: We’re revisiting this series on navigating by the sun, moon, stars and planets in the age of GPS because celestial nav is not only a viable backup to satellite navigation, but it is also a skill that ocean voyagers should have in their toolkit. During the next few issues, we’ll cover all the basic knowledge you’ll need to get up to speed on this elegant and rewarding technique for finding your way at sea. A thumbnail sketch Imagine yourself as a little stick figure of a human standing somewhere on the Earth’s surface. That’s your position. You’re not exactly sure where it is in terms of latitude and longitude, but you have a good idea. Call that your dead reckoning (DR) position. Now also imagine that the sun’s…
Skipper Ron Wisner, of Marion, Mass, sets sail today for Bermuda in the 48-year-old ship Hotspur II to compete in the Marion Bermuda race for the fourth time, racing in the class of celestial navigators. The art of celestial navigation developed over centuries. Ron is not continuing the tradition out of nostalgia or for historical interest, for him it is an essential tool for mariners the world over, for safety reasons and as a practice of good seamanship. ON: What is the Marion Bermuda all about? RW: The Marion Bermuda is a smaller race then the Newport race. It’s more intimate and many sailors, if not most, know each other. The challenges are that it’s a mix of boats, many cruisers, some fast as well, and so every boat has its…
