A sextant is a doubly reflecting navigation instrument that measures the angular distance between two visible objects. The primary use of a sextant is to measure the angle between an astronomical object and the horizon for the purposes of celestial navigation. The estimation of this angle, the altitude, is known as sighting or shooting the object, or taking a sight. The angle, and the time when it was measured, can be used to calculate a position line on a nautical or aeronautical chart—for example, sighting the Sun at noon or Polaris at night (in the Northern Hemisphere) to estimate latitude (with sight reduction). Sighting the height of a landmark can give a measure of distance off and, held horizontally, a sextant can measure angles between objects for a position on a chart. A sextant can also be used to measure the lunar distance between the moon and another celestial object (such as a star or planet) in order to determine Greenwich Mean Time and hence longitude.The principle of the instrument was first implemented around 1731 by John Hadley (1682–1744) and Thomas Godfrey (1704–1749), but it was also found later in the unpublished writings of Isaac Newton (1643–1727). In 1922, it was modified for aeronautical navigation by Portuguese navigator and naval officer Gago Coutinho. (Wikipedia).
Sexting has a pretty low reputation, yet another part of our sexuality we dismiss as low and trivial – but it can, in certain forms, capture a lot of what is most moving about relationships in general. If you like our films take a look at our shop (we ship worldwide): http://www.theschoolo
From playlist RELATIONSHIPS
23C3: Pornography and Technology
Speaker: Tina Lorenz a love affair Pornography is an abstract phenomenon. It cannot exist without a medium to propagate it, and it has very little (if anything at all) to do with sex. The relationship between pornography, which is entirely fictional and sex, which is very real, very swe
From playlist 23C3: Who can you trust
Birth of the Vibrator | Original Sin: Sex
Experts like Dr. Drew reveal the invention of the vibrator, which originally served as a cure for "hysteria" in Victorian Era women. ➡ Subscribe: http://bit.ly/NatGeoSubscribe About National Geographic: National Geographic is the world's premium destination for science, exploration, and
From playlist Original Sin: Sex | National Geographic
Thoughtful people tend instinctively to believe that using sex to sell things is a really degrading activity. But might it not at least in part depend on what you happen to be selling? Please help us to make films by subscribing here: http://tinyurl.com/o28mut7 Brought to you by http://www
From playlist WORK + CAPITALISM
How to Not Treat Sexy Women Like Sex Objects
What's the difference between being attracted to women and sexually objectifying women? Share this on Facebook: http://on.fb.me/1M9eFTB Share this on Twitter: http://ctt.ec/HbWcs Subscribe: http://bit.ly/1l8JXv3 On the web: http://www.stuffmomnevertoldyou.com/ Twitter: https://twitte
From playlist Media Stuff
The Old Sailors' Tool That Saved Apollo 13
In the 1700s, sailors used sextants to navigate the seas. Centuries later, these old-timey tools saved the day on not one, but two of the Apollo missions! Hosted by: Reid Reimers SciShow has a spinoff podcast! It's called SciShow Tangents. Check it out at http://www.scishowtangents.org -
From playlist SciShow Space
The Sexiness of Bookish People
Bookish people are not obvious pin-ups. And yet they sometimes have an allure all of their own, which deserves to be celebrated and remarked upon – so that intellectual life can retain the prestige and glamour it requires. If you like our films take a look at our shop (we ship worldwide):
From playlist RELATIONSHIPS
This seminar will describe Celestial Navigation at sea, and how it can be combined with other information to form a useful ocean navigation process. If you ever wanted to know what celestial navigation was all about, this is your primer...
From playlist Space Navigation Playlist
A Guide To Navigating the Stars Without a Smartphone
What happens when you’re lost and you don’t have your phone or any recognizable landmarks to give you directions? Well, you look up at the stars. » Subscribe to Seeker! http://bit.ly/subscribeseeker » Visit our shop at http://shop.seeker.com » Catch up on Constellations! https://bit.ly/3uK
From playlist Constellations | Seeker
NASA's Sextant Mission To Navigate By Neutron Stars | Video
NASA's Goddard Space Flight Center is developing a new instrument that uses the natural beacons of pulsar radiation, to let spacecraft find their way in deep space. A test on ISS is planned.
From playlist Space Navigation Playlist
Forget GPS, Future Missions May Use Neutron Stars to Navigate Deep Space
Lighthouses have helped safely guide mariners for centuries. As space explorers consider traveling to far-flung destinations, could pulsars provide them with similar guidance? » Subscribe to Seeker! http://bit.ly/subscribeseeker » Watch more Elements! http://bit.ly/ElementsPlaylist » Visi
From playlist Elements | Seeker
From the album "Sexwitch" (2015). I do not own or have any rights over this song, nor do I intend to profit from sharing it.
From playlist Dave's favorite music of 2015
TabletClass.com - http://www.tabletclass.com Math. This video explains the basics of how math is used in celestial navigation. When people first started to navigate by stars a massive explosion in trade and culture developed. Celestial navigation requires the use of a sextant, clock and
From playlist Science Videos
RubyConf 2015 - Keynote: Leagues of Sea and Sky by Jeff Norris
Keynote: Leagues of Sea and Sky by Jeff Norris In this keynote, Jeff tells three stories of inventions for nautical and aeronautical exploration to reveal how partnership has shaped the greatest journeys in history and how it should shape your own. From the sextant to holographic mixed re
From playlist RubyConf 2015
How does math guide our ships at sea? - George Christoph
View full lesson: http://ed.ted.com/lessons/how-does-math-guide-our-ships-at-sea-george-christoph Without math, would our seafaring ancestors ever have seen the world? Great mathematical thinkers and their revolutionary discoveries have an incredible story. Explore the beginnings of logar
From playlist Even More TED-Ed Originals
SciShow Quiz Show: The Science of Puppies!
SciShow Quiz Show is back, with familiar faces Hank Green and Lindsey Doe matching wits about ancient science, puppies, and all kinds of words that have “sex” in them! https://www.youtube.com/user/sexplanations Hosted by: Michael Aranda ---------- Dooblydoo thanks go to the following Pat
From playlist SciShow Quiz Show
Sex on Wheels | Original Sin: Sex
Experts like Dr. Ruth explore how the car played an unlikely role in the sexual revolution. ➡ Subscribe: http://bit.ly/NatGeoSubscribe About National Geographic: National Geographic is the world's premium destination for science, exploration, and adventure. Through their world-class sci
From playlist Original Sin: Sex | National Geographic
Space Navigation. Finding Your Way in the Cosmos
Until we learned to properly navigate our way across the oceans, early explorers were fearful to lose sight of land in case they’d be lost at sea. They learned to use the water currents, winds, movements of birds and of course, the positions of the Sun, the Moon and the stars to find their
From playlist Guide to Space
When Sex Turns Lethal | Original Sin: Sex
Experts like Dan Savage discuss how HIV/AIDS forged bonds within the gay community and catapulted the fight to legalize gay marriage. ➡ Subscribe: http://bit.ly/NatGeoSubscribe About National Geographic: National Geographic is the world's premium destination for science, exploration, and
From playlist Original Sin: Sex | National Geographic