MnAstro Forums

Is there anyone with working knowledge of a sextant?
I have one and wish to learn more about it and how to use it along with my telescope.
Sure after I program my telescope most anything in the sky is just a button away, but knowing how to find my location by using a sextant would be cool.

Wow, that is neet piece of hardware.
I have a basic understanding of the use.
There are many good resources online, but the main use is to measure the "altitude", or angular height of a celestial object (sun, moon, bright star) above the horizon. Your latitude can be measured by doing this with Polaris. It works best over water with a good view of the horizon. Longitude requires an accurate GMT time, compass, and tables. It can also be used to accurately measure other angles.
I plan to be at the March meeting.
A good resource and video is at:
marineinsight.com/marine-navigation/what-is-a-sextant
Matt

Nice Instrument!!

This probably goes further than your question, but to know the history of how both sextants and chronometers were critical to finding your location at sea would give you an in-depth view and history of your wonderful instrument.
https://en.wikipedia.org/wiki/Marine_chronometer

Thank you both for replying and offering links to further fuel and improve my sextant knowledge.
Will likely keep it with my telescope gear and have it along when at future meetings.

I used a sextant as an Air Force navigator. I brought a B-52 from the west coast of the US to Guam using the Sun and Venus, along with variations in pressure. I am here so I did find the island. We were only a few miles from my calculated position after that distance and time. It works! We used a bubble sextant on aircraft, which is a bit different than this sextant for use on land and sea. The purpose of the device is to measure the angle of the observed object above the horizon. While this sextant and the bubble sextant are functionally different, the resultant viewed angle will be the same value. Based on date, time, and object information from an ephemeris you will get a line of position on the surface of the earth. You can use an astronomical sky program that gives apparent altitude of objects instead of an ephemeris. Details are a bit complex for this post. I would be happy to take this discussion further with you. Let me know.