Southern Cross, southern sky, Gacrux (APOD 07 Jul 2008)

[neufer]

http://apod.nasa.gov/apod/ap080707.html
http://antwrp.gsfc.nasa.gov/apod/ap070517.html
http://antwrp.gsfc.nasa.gov/apod/ap050129.html
http://www.daviddarling.info/encyclopedia/G/Gacrux.html

Marvelous article on Gacrux:

http://www.solstation.com/stars2/gacrux2.htm

[apodman]

My interest was all in the Southern Cross. I had never seen that. I had heard about it all my life, and it was but natural that I should be burning to see it. No other constellation makes so much talk. I had nothing against the Big Dipper - and naturally couldn't have anything against it, since it is a citizen of our own sky, and the property of the United States - but I did want it to move out of the way and give this foreigner a chance. Judging by the size of the talk which the Southern Cross had made, I supposed it would need a sky all to itself.

But that was a mistake. We saw the Cross tonight, and it is not large. Not large, and not strikingly bright. But it was low down toward the horizon, and it may improve when it gets up higher in the sky. It is ingeniously named, for it looks just as a cross would look if it looked like something else. But that description does not describe; it is too vague, too general, too indefinite. It does after a fashion suggest a cross - a cross that is out of repair - or out of drawing; not correctly shaped. It is long, with a short cross-bar, and the cross-bar is canted out of the straight line.

It consists of four large stars and one little one. The little one is out of line and further damages the shape. It should have been placed at the intersection of the stem and the cross-bar. If you do not draw an imaginary line from star to star it does not suggest a cross - nor anything in particular.

One must ignore the little star, and leave it out of the combination - it confuses everything. If you leave it out, then you can make out of the four stars a sort of cross - out of true; or a sort of kite - out of true; or a sort of coffin - out of true.

Constellations have always been troublesome things to name. If you give one of them a fanciful name, it will always refuse to live up to it; it will always persist in not resembling the thing it has been named for. Ultimately, to satisfy the public, the fanciful name has to be discarded for a common-sense one, a manifestly descriptive one. The Great Bear remained the Great Bear - and unrecognizable as such - for thousands of years; and people complained about it all the time, and quite properly; but as soon as it became the property of the United States, Congress changed it to the Big Dipper, and now everybody is satisfied, and there is no more talk about riots. I would not change the Southern Cross to the Southern Coffin, I would change it to the Southern Kite; for up there in the general emptiness is the proper home of a kite, but not for coffins and crosses and dippers.

[neufer]

http://en.wikipedia.org/wiki/Crux

<<Crux, commonly known as the Southern Cross, is the smallest of the 88 modern constellations, but nevertheless one of the most distinctive. It is surrounded on three sides by the constellation Centaurus, and to the south lies Musca. Ancient Greeks originally considered Crux to be part of Centaurus; however, the precession of the equinoxes gradually lowered these stars below the European horizon, and they were eventually forgotten. (At the latitude of Athens in 1000 B.C., Crux was clearly visible, though low in the sky; by 400 A.D., most of the constellation never rose above the horizon for Athenians.) The five brightest stars of Crux (α, β, γ, δ, and ε Crucis) appear on the flags of Australia, Brazil, New Zealand (epsilon omitted), Papua New Guinea, and Samoa.>>

http://antwrp.gsfc.nasa.gov/apod/ap010618.html

[Carl Horn]

G'day,
Not only does Australia show the Southern Cross on its national flag, so does New Zealand! (No, we're not the sixth state of Australia.)
Cheers, Carl
Nelson, New Zealand

[83d]

The Southern Cross is such a famous constellation that it is depicted on the national flag of Australia.

The Southern Cross officially appeared on the Australian flag in 1954. Long before that, in 1902, it was on the national flag of New Zealand.

The Southern Cross is also a handy navigation aid. Not having a pole star in our hemisphere, we find due South about 4 cross-lengths "down" from the bottom star of the cross, or if the sky is clear enough, about mid-way between the Southern Cross and Achernar.

[neufer]

The Southern Cross is such a famous constellation that it is depicted on the national flag of Australia.

The Southern Cross officially appeared on the Australian flag in 1954. Long before that, in 1902, it was on the national flag of New Zealand.

1954 Australian flag:
http://en.wikipedia.org/wiki/Image:Flag ... tralia.svg

1901 Australian flag:
http://en.wikipedia.org/wiki/Image:Flag ... 1-1903.svg
---------------------------------------------------
http://en.wikipedia.org/wiki/Flag_of_Australia

<<On 3 September 1901, the new Australian flag flew for the first time atop the Royal Exhibition Building in Melbourne. A simplified version of the competition-winning design was officially approved as the Flag of Australia by King Edward VII in 1902.>>
---------------------------------------------------
http://en.wikipedia.org/wiki/Coat_of_arms_of_Brazil
http://commons.wikimedia.org/wiki/Image ... 960%29.svg

<<The Coat of arms of Brazil was created in November 19, 1889, four days after Brazil became a republic. The coat of arms consists of the central emblem surrounded by coffee (at the left) and tobacco (at the right) branches, which were important crops in Brazil at that time. In the blue circle in the center, the Southern Cross (also known as Crux) can be seen.>>

[83d]

... the flag ... had no legal status beyond the original British Admiralty authorisations which only related to use at sea. It wasn't until the Flags Act 1953 (enacted 1954) ... that Australia finally had an official national flag ...

http://www.ausflag.com.au/history.html

I'll stop now.

[orin stepanek]

Interesting History lesson. I wasn't aware that the Southern Cross was on any flag. I think that's neat that it is.
Orin

[bystander]

When you see the Southern Cross for the first time
You understand now why you came this way
'Cause the truth you might be runnin' from is so small.
But it's as big as the promise, the promise of a comin' day.

[fuelie]

Aloha everyone,

Could someone clarify the status of the Southern Cross as a Constellation versus an Asterism? The July 7 APOD stated that it is a Constellation while an Astronomy program called StarGazer from Carina Software in
California lists it among the common Asterisms. I suspect their Voyager program also calls it an Asterism.

This web site doesn't show it as an Asterism. http://www.wro.org/ras/asterism.htm. Does this site contain all known Asterisms?

Mahalo Nui Loa,

Fuelie

[bystander]

Could someone clarify the status of the Southern Cross as a Constellation versus an Asterism?

http://en.wikipedia.org/wiki/Constellation

In common usage, a constellation is a group of stars that are connected together to form a figure or picture. The term is also traditionally and less formally used to mean any group of stars visibly related to each other, if they are considered as a fixed configuration or pattern in a particular culture.
...
The astronomical definition of constellation is slightly different, however. A group of stars that can be connected to form a figure or a picture is called an asterism, while a constellation is an area on the sky. The International Astronomical Union (IAU) divides the sky into 88 official constellations with exact boundaries, so that every direction or place in the sky belongs within one constellation.
...
A star pattern may be widely known but may not be recognized by the IAU; such a pattern of stars is called an asterism.

The Southern Cross is listed as one of the 88 official IAU constellations. It's official nomenclature is Crux.

http://en.wikipedia.org/wiki/List_of_constellations
http://en.wikipedia.org/wiki/Crux

[Indigo_Sunrise]

Excellent question, fuelie! And equally exellent response, bystander!
Thanks for the clarification! 8)

[fuelie]

Aloha Bystander,


Thanks for the clarification. I shall forward this information to Carina Software so the company can move Crux from its list of Asterisms to its list of Constellations in both astronomy programs.

Malama Pono ( Take Care )

Fuelie