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
Longitude by Lunars
"Lunar Distances" or lunars for short were used to determine longitude at sea in the period from about 1767 until 1850 (and rarely after that date). This was a time when chronometers were not yet widely available at a reasonable price and were considered unreliable on long voyages. The principle behind lunars is simple. The Moon in the sky is the hour hand of a great clock. The stars along its path are the numbers on the face of the clock. If we can measure the Moon's position relative to the stars, we can read the time from the clock. Comparing that absolute time with local time, usually determined by a time sight, we have our longitude. A one hour difference in time corresponds to a 15 degree difference in longitude.-
Predicted Lunars (UPDATED)
Traditionally, lunar distances could be used for navigation only if a navigator had access to predicted distances. These were published in almanacs around the world from the late 18th through the early 20th centuries. Today the predicted distances are no longer published, but they can be calculated without much difficulty. The predictions generated by this web site are extremely accurate. They are the most accurate available today. The time period covered is 1750 to 2050 so the predictions here can be used for modern lunars or for analysis of historical lunar observations. -
Clear a Lunar (UPDATED)
This web-based app will analyze a lunar observation and generate your longitude in a fraction of a second. Historically, the analysis of lunars required about twenty minutes of work and a table of logarithms. Even if you decide to work a lunar by hand with pencil and paper, this online calculator will allow you to check your results. Originally developed and made available online in the summer of 2004, this app has been field-tested by myself and other navigation enthusiasts thousands of times. Its results are accurate to approximately one second of arc. -
Online Nautical Almanac (UPDATED)
A complete source for Nautical Almanac ephemeris data covering the period 1750 to 2050. The positions of the Sun, Moon, navigational planets and stars are generated for every hour of the day at a high level of accuracy just as in the published almanacs. This online app permits customization of display options so that data are generated that are relevant for your location and interests. -
Easy Lunars
An account of a simple technique for analyzing lunars using nothing more than the basic corrections and data in the Nautical Almanac and a handheld calculator. Lunars are not difficult. They take a little practice, and you may have to re-familiarize yourself with the use of a calculator, but any navigator can enjoy the challenge and experience of this historical method of navigation.
Comments:
John Brown wrote: 6👍
Philip M. Sadler wrote: 85👍
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
Philip M. Sadler, Ed.D.
F.W. Wright Senior Lecturer in Celestial Navigation
Harvard University Astronomy Department
Cambridge, MA
John Workman wrote: 20👍
I just took one of Franks classes and it was awesome!!
Frank taught an incredible class on celestial navigation that brought me from novice to some solid understanding of sextants, their history and most importantly their use as a aid to seeing the sea...and knowing where you are on this planet!
Hands on, wealth of knowledge, great resources ... he really covered a lot of ground! There was a lot of math but unlike in my youth, I was on the edge of my seat to soak up knowledge!! Frank made it relatable and real. The sextant which is such an iconic tool of the sea, was demystified. By the end of class i felt comfortable with it. I had mastered how it worked, how to read it and how to adjust it to insure its accuracy.
I came away with all of the cheat sheets and understandings of equations and concepts that breathe the life into what you capture through your sextant sightings.
I would highly recommend Frank and believe Mystic Seaport with its planetarium, an ideal setting for my class with him discovering this timeless tool of the sea.
Frank did a great job keeping the class interesting with visual aids, both on screen and out on the Seaport grounds.
All in all i would highly recommend this class to any and all folks interested in learning about navigation and sextants. Informative and digestible, but most of all useful to the point where i am comfortable with the instrument and have the formulas needed to continuing to set my sights on the horizon!!
I look forward to more classes to learn more from Frank and strengthen my understandings of celestial navigation!
Thank you!!!
John
Frank taught an incredible class on celestial navigation that brought me from novice to some solid understanding of sextants, their history and most importantly their use as a aid to seeing the sea...and knowing where you are on this planet!
Hands on, wealth of knowledge, great resources ... he really covered a lot of ground! There was a lot of math but unlike in my youth, I was on the edge of my seat to soak up knowledge!! Frank made it relatable and real. The sextant which is such an iconic tool of the sea, was demystified. By the end of class i felt comfortable with it. I had mastered how it worked, how to read it and how to adjust it to insure its accuracy.
I came away with all of the cheat sheets and understandings of equations and concepts that breathe the life into what you capture through your sextant sightings.
I would highly recommend Frank and believe Mystic Seaport with its planetarium, an ideal setting for my class with him discovering this timeless tool of the sea.
Frank did a great job keeping the class interesting with visual aids, both on screen and out on the Seaport grounds.
All in all i would highly recommend this class to any and all folks interested in learning about navigation and sextants. Informative and digestible, but most of all useful to the point where i am comfortable with the instrument and have the formulas needed to continuing to set my sights on the horizon!!
I look forward to more classes to learn more from Frank and strengthen my understandings of celestial navigation!
Thank you!!!
John
