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What Northern Hemisphere Astronomers Are Missing From the Southern Hemisphere
creimer (824291) writes The New York Times Sunday Review has an interesting article on the astronomical night life when viewed from Sao Paulo, Brazil, featuring a treasure trove not visible to astronomers in the Northern Hemisphere: "Yet the Southern Hemisphere claims the three brightest stars of the night sky: Sirius, Canopus and Alpha Centauri. Canopus belongs to the Carina constellation, notorious for two things: the Carina Nebula, four times as large and even brighter than the famous Orion Nebula, and the star system Eta Carinae, which is expected to burst as a supernova or hypernova sometime in the next thousand years. (A scientist told the BBC that the explosion would be so bright that you would see it during the day, and you could even read a book by its light at night.) Alpha Centauri and Beta Centauri, the 11th-brightest star, are called "The Pointers," as they form a line in the sky to the constellation Crux (the Southern Cross). Crux is the smallest of all 88 constellations but one of the most distinctive. It is visible at practically any time of the year in all of the Southern Hemisphere."
I mean, yes, it's true. And yes, it's interesting. But ... news?
We used to have a Bill of Rights. Now, with the rights gone, all we have left is the bill.
...but, in terms of widely recognized asterism shape, Delphinus and Sagitta are both smaller. Sure, as the sky is officially divvied up and assigned to constellations, Crux gets the smallest area -- but those divisions seem about as respectable as gerrymandered congressional districts in the US.
Just to view the southern sky from the Atacama Desert. Clear skies far from light pollution. I need to see these sights. Those and the LMC and SMC.
Of course, the majority of humans now live in urban areas, and see little or nothing of the night sky at all, whether northern or southern. Perhaps I'm taking this a step too far, but would it be possible that we'll see a continuing decline in interest and support for astronomy and space technology as more and more voters and influential people grow up and live their lives without ever really seeing the skies?
Trust the Computer. The Computer is your friend.
And the wavelengths the LEDs are putting out - emission spectroscopy is what you are looking for.
One positive is a lot of the new lights have fittings that reflect the light more in the direction where it is useful. It's easier to design such things for lights that are not very hot.
Crux is very useful for navigating at night. From wikipedia:
In the Southern Hemisphere, the Southern Cross is frequently used for navigation in much the same way that the Pole Star is used in the Northern Hemisphere. Alpha and Gamma (known as Acrux and Gacrux respectively) are commonly used to mark south. Tracing a line from Gacrux to Acrux leads to a point close to the Southern Celestial Pole.[3] Alternatively, if a line is constructed perpendicularly between Alpha Centauri and Beta Centauri, the point where the above-mentioned line and this line intersect marks the Southern Celestial Pole. Another way to find south, strike line through Gacrux and Acrux, 3 1/2 times the distance between Gacrux and Acrux, directly below that point is south.
They sentenced me to twenty years of boredom
The phrase "smallest of all 88 constellations" really irks me. Constellations aren't real things, they're imaginative descriptions of patterns people see to make it easier to remember which stars are which. There's at least one constellation "The Triangle*" which is smaller, or if you allow two-star constellations, "those two faint dots over there" is even smaller.
(*Yes, I stole that The Triangle from Terry Pratchett; it's the name of a Discworld constellation.)
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks