Sextans – the sextant

September 18, 2016


coord_altazThere is a small constellation smack dab on the celestial equator called Sextans. Don’t worry, it’s safe for work, although the sex part might get it snagged by parental filters, I wouldn’t know. It’s part of a group of constellations named in the 17th century in order to fill in some of the holes in the map. They are named after major inventions of the time that changed the world. If they were being named today they would be called things like “Smart Phone” and “Viagra” and so forth.

The area only has one noticeable star, Alpha Sextantis. The rest are on the very edge of notice-ability. But looking deeper, we’ve noticed there are some Population III stars here, some of the oldest stars in the whole Universe as far as we know. These are the grandpappy and grandmammy stars. If you like heavy metal, then you can thank these old timers for mining the raw ore back before metal became a thing.
Connecting the dots you get a shallow angle, like the one made by its namesake, the sextant, when measuring an object near the horizon. The device, by the way, is the oldest bit of technology on board spaceships. When Apollo 13 blew up on route to the Moon and their computer puked, the crew used a sextant to navigate their way back to Earth. You might guess that they could just look out the window and head for the big blue thing, but it actually demands more precision than that.
The galaxy NGC-3115 can be found here but it’s pretty dim so use a big telescope or at least a big imagination. It’s paper-thin and we see it edge on, so it’s basically just a line. The cool thing about it is that the core contains a supermassive blackhole that weighs about a billion times as much as our sun. Even better, we seem to be seeing the blackhole in the process of swallowing a star. That’s awesome unless, you know, you live on a planet orbiting that star.

star-pilot_01Sextans was named by Johannes Hevelius in 1687 and it is not associated with any myths, other than the ones Hevelius told women about himself when the bars were closing.

Carpe Noctem.

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