Calibrating and Using A Sextant

A 15 minute video that shows how to calibrate a sextant and use a sextant to take a celestial shot using both a true and artificial horizon.

[@jamescook4143]

We have a Coastal Navigation course (9 - 3 hour sessions) that goes over multiple techniques for emergency navigation. The entire course is based on the premise that the boat has lost all electricity, so there is no GPS, no Depthsounder, no Knotmeter, etc, etc. We use current charts from 5 different countries showing you how to enter foreign harbors and the old tricks of the trade.

[@jamescook4143]

Either way will work, with your instructions, you will use the altitude corrections for the lower limb. With the method shown in my video, you use the altitude corrections for a star. The difference between the two, is the semi-diameter of the sun.

[@darrenrigg5334]

Quality video, made more sense than hours of reading. Thanks

[@ClaytheOwen]

Thank-you for this video. I was browsing KZbin and thought "I wonder how you use a sextant?". Perfect introductory video to taking shots.

[@PCFithian]

Great video, please post more on how to use a sextant for emergency navigation.

[@AR-iy7oy]

Very informative. Thankyou this will be another ´string to my bow´.

[@jamescook4143]

What do you mean by a +3 mile error - after you have solved the shot, you now have a 7 mile error? If the 3 mile error remains the same after looking at a star, going and using the drum to set the 2 starts one on top of the other, then that is probably you index error.

[@588158]

Well done! Absolutely first rate instructing! Question,can you navigate exclusively by the sun or must you also take star and moon shots? I have been told that there is a great deal of error in star and moon shots.

[@BobbieGWhiz]

Hi, nice instructional video. I have a question. Since the reflected image of the celestial body shows up both in the clear portion and the mirrored portion of the horizon mirror , why is the mirrored portion necessary. The clear portion also reflects the celestial body. It seems as if the clear portion of the split image mirror acts as a whole horizon mirror, ie. It both reflects the celestial body, and transmits the view of the horizon. Thanks very much.

[@jamescook4143]

You need two rays of light for the sextant to work, one being reflected from the celestial body and one coming from the horizon.

[@588158]

Absolutely the best video on the sextant. I have a mark15 and am confused about placement of sextant image when using an artificial horizon. The instructions for my artificial horizon says " bottom of the double reflected image is brought into coincidence with the top of the image on the liquid for a lower limb observation." This is dfferent from what you showed. Is this because I have a split horizon mirror?

[@BlackLabAdventures]

Terrific Video!!!