APOD: The Southern Cross in a Southern Sky (2015 Oct 19)

[APOD Robot]

The Southern Cross in a Southern Sky

Explanation: Have you ever seen the Southern Cross? This famous constellation is best seen from Earth's Southern Hemisphere. Captured from Rio de Janeiro, Brazil, the four bright stars that mark the Southern Cross are visible just above the horizon in the featured image. On the left of this constellation, also known as The Crux, is the orange star Gamma Crucis. The band of stars, dust, and gas rising through the middle of the image mosaic is part our Milky Way Galaxy. Just to the right of the Southern Cross is the dark Coal Sack Nebula, and the bright nebula at the top of the image is the Carina Nebula. The Southern Cross is such a famous constellation that it is depicted on the national flag of Australia.

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[/b]

[Nitpicker]

This image was taken from the dark skies of Itatiaia, in the state of Rio de Janeiro, about 150 km WNW of the city of Rio de Janeiro. It was taken before dawn on 18 November 2014.

Of course, The Southern Cross is also depicted (mirrored!) on the Brazilian flag, where it is "intended to represent the stars in the sky at Rio de Janeiro at 8:30 in the morning on 15 November 1889, the moment at which the constellation of the Southern Cross was on the meridian of Rio de Janeiro and the longer arm [of the cross] was vertical." ref https://en.wikipedia.org/wiki/Flag_of_Brazil

[Ann]

That's a lovely image!

I love all the clusters and nebulas here. Apart from the Coal Sack Nebula and the great Carina Nebula, which are featured in the APOD caption, we can see (from the bottom to the top) the Jewel Box cluster, the large Running Chicken nebula, the clusters NGC 3766 and IC 2714 - hard to see in the picture I posted! - the large, impressive NGC 3532, the bright Southern Pleiades, IC 2602, the Gabriela Mistral Nebula, NGC 3324, NGC 3293, and finally NGC 3114.

What a bonanza of nebulas and clusters! This is a great APOD!

Ann

[Ingar Clausen]

Southern Cross and Carina Nebula.
Watching the photo of today I just wonder that some patters appearing under the Carina Nebula shows vertical like double light points like watching light poles along a highway from the air. The stars appear like :::::::::::::::::::::::::: but vertically, an are visualized by enlarged photo versions. But you must search for patterns to discover them.
HOW COME ?

Ingar Clausen, ingarclausen@gmail.com
Østre Klyveveg 4
N-3919 Porsgrunn Norway

[KiwiBill]

The Australian flag does include the Southern Cross among its seven stars. The very similar New Zealand flag features only the four stars of the Southern Cross.

[Ann]

Southern Cross and Carina Nebula.
Watching the photo of today I just wonder that some patters appearing under the Carina Nebula shows vertical like double light points like watching light poles along a highway from the air. The stars appear like :::::::::::::::::::::::::: but vertically, an are visualized by enlarged photo versions. But you must search for patterns to discover them.
HOW COME ?

Ingar Clausen, ingarclausen@gmail.com
Østre Klyveveg 4
N-3919 Porsgrunn Norway

I think you more or less gave us the answer yourself - you must search for patterns to discover them. Human beings are very good at seeing patterns, and in fact, we are so good at it that we sometimes see patterns where there are none.

You are watching a specific photo. It could be that another photo, with a higher resolution, would show you that the pattern isn't really there. Many photographs "enhance" the brightness of stars of certain magnitudes, while "suppressing" stars of other magnitudes, making false patterns appear.

Here is another picture of the same patch of the sky. Do you see the same patterns here?

It is possible - possible, mind you - that we are seeing long lines of stars that formed along a shock front of some sort in the Carina Nebula. But we can't say that for certain unless we know the distances to the stars in the apparent lines. It could well be that some are foreground stars and other background stars, in which case the apparent "lines" become illusions.

Ann

[akademy]

So how many stars do we see here? My rough estimate puts it at around 5000 but Is it safe to assume that the points of light are stars instead of bright nebulas, or galaxies.

[starsurfer]

Could a wide angle lens image like this also include Ha exposures as well?

[Chris Peterson]

Could a wide angle lens image like this also include Ha exposures as well?

Yes, but with some caveats. First, this was made with a consumer camera that normally has an IR blocking filter which cuts off a lot of Ha. I think this particular camera was custom modified to remove that filter, but that's a fairly uncommon mod (and it makes the camera much less useful for ordinary photography). Second, narrowband optical filters don't work very well with camera lenses, particularly with wide angle lenses. That's because they need to operate with the light rays passing through as nearly perpendicular to the filter face as possible, and a wide angle camera lens has highly divergent rays on both sides. This broadens the bandpass of the filter, and also shifts the center band as you move away from the optical axis.

[neufer]

Mark Twain: _Following the Equator_ Page 27

<<We are moving steadily southward-getting further and further down under the projecting paunch of the globe. Yesterday evening we saw the Big Dipper and the north star sink below the horizon and disappear from our world. No, not "we," but they. They saw it--somebody saw it--and told me about it. But it is no matter, I was not caring for those things, I am tired of them, any way. I think they are well enough, but one doesn't want them always hanging around. 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 to-night, 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 across 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 every body 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. In a little while, now--I cannot tell exactly how long it will be--the globe will belong to the English- speaking race; and of course the skies also. Then the constellations will be re-organized, and polished up, and re-named--the most of them "Victoria," I reckon, but this one will sail thereafter as the Southern Kite, or go out of business.>>

[Ingar Clausen]

Southern Cross and Carina Nebula.
Watching the photo of today I just wonder that some patters appearing under the Carina Nebula shows vertical like double light points like watching light poles along a highway from the air. The stars appear like :::::::::::::::::::::::::: but vertically, an are visualized by enlarged photo versions. But you must search for patterns to discover them.
HOW COME ?

Ingar Clausen, ingarclausen@gmail.com
Østre Klyveveg 4
N-3919 Porsgrunn Norway

I think you more or less gave us the answer yourself - you must search for patterns to discover them. Human beings are very good at seeing patterns, and in fact, we are so good at it that we sometimes see patterns where there are none.

You are watching a specific photo. It could be that another photo, with a higher resolution, would show you that the pattern isn't really there. Many photographs "enhance" the brightness of stars of certain magnitudes, while "suppressing" stars of other magnitudes, making false patterns appear.

Here is another picture of the same patch of the sky. Do you see the same patterns here?

It is possible - possible, mind you - that we are seeing long lines of stars that formed along a shock front of some sort in the Carina Nebula. But we can't say that for certain unless we know the distances to the stars in the apparent lines. It could well be that some are foreground stars and other background stars, in which case the apparent "lines" become illusions.

Ann

Hi Ann !
Thank you for an answer that may be somehow correct. But taking another look at todays picture, and normal magnification according to APOD click and point possibillity, I cannot find that part of the picture may give sort of mirror effect on other sections or parts of that picture. Over the last 7-8 years I have daily studied the images given by APOD, and never discovered something like mentioned in my first part of discussion.
You picture which is more blurry than the APOD's show nothing like my observation, possibly because no option to magnify and out of focus.
And therefor I find myself not able to create some illusions on this observation, but just seeing what I see, and that's it!
Anyone else able to see tha same as I, may explain to me on ingarclausen@gmail.com.
INGAR

[ta152h0]

Yes, I lived under it near Sao Paulo for 18 years. And clear skies. I have a quick question about Eta Carinae . When she blows, is the solar system going to get bathed in a light that allows our telescopes to get a really good look at the asteroid belt ?

[Chris Peterson]

Yes, I lived under it near Sao Paulo for 18 years. And clear skies. I have a quick question about Eta Carinae . When she blows, is the solar system going to get bathed in a light that allows our telescopes to get a really good look at the asteroid belt ?

Why would it? We already get a good look at the asteroid belt, which is lit more brightly by the Sun by many orders of magnitude than any nearby supernova will manage.

[neufer]

Yes, I lived under it near Sao Paulo for 18 years. And clear skies. I have a quick question about Eta Carinae . When she blows, is the solar system going to get bathed in a light that allows our telescopes to get a really good look at the asteroid belt ?

Why would it? We already get a good look at the asteroid belt, which is lit more brightly by the Sun by many orders of magnitude than any nearby supernova will manage.

A normal Type Ia supernova is ~5 billion (~71,000²) times brighter than the Sun and thus would appear as bright as the Sun if it were ~71,000 times as far away. Since light-year is ~63,000 AU, an Ia supernova would have to be about a light-year away to be brighter than the Sun for us (or about 7 light-years away to be brighter than the Sun for a Kuiper Belt object).

[Chris Peterson]

Yes, I lived under it near Sao Paulo for 18 years. And clear skies. I have a quick question about Eta Carinae . When she blows, is the solar system going to get bathed in a light that allows our telescopes to get a really good look at the asteroid belt ?

Why would it? We already get a good look at the asteroid belt, which is lit more brightly by the Sun by many orders of magnitude than any nearby supernova will manage.

A normal Type Ia supernova is ~5 billion (~71,000²) times brighter than the Sun and thus would appear as bright as the Sun if it were ~71,000 times as far away. Since light-year is ~63,000 AU, an Ia supernova would have to be about a light-year away to be brighter than the Sun for us (or about 7 light-years away to be brighter than the Sun for a Kuiper Belt object).

And if there's a supernova a light year away, nobody is going to be worrying about a good view of the asteroids!

[neufer]

[b][color=#0000FF]Any resemblance to the Vacationer at Tralfamadore is purely coincidental.[/color][/b]

---

And if there's a supernova a light year away, nobody is going to be worrying about a good view of the asteroids!

• Well...possibly one guy:

<<Professor John Nerdelbaum Frink, Jr. is Springfield's stereotypical nerdy, mad, and socially inept scientist, inventor, and mathematician. He wears thick glasses, a white lab coat, pink pants, and has buckteeth. Frink is a college professor at Springfield Heights Institute of Technology and runs his own astronomical observatory. He has an IQ of 197 – it was 199 before he sustained a concussion during the collapse of Springfield's brief intellectual junta – and is a member of the Springfield chapter of Mensa. Frink is generally very polite and friendly. He has a trademark mannerism of using Jerry Lewis-style gibberish when excited, such as "HOYVIN-GLAVIN!" and "FLAVIN" and impulsively shouting other words that have no relevance to the situation at hand. He also occasionally refers to the importance of remembering to "carry the one" in various mathematical calculations. When he rambles he often speaks incoherently in run-on sentences without pauses. Frink also has a tendency to over-complicate simple matters and/or invent scientific terminology while expressing various concepts, e.g. "Father and I got along like positrons and antineutrinos!" or, "microcalifragilistics".>>

[Chris Peterson]

And if there's a supernova a light year away, nobody is going to be worrying about a good view of the asteroids!

• Well...possibly one guy:

Okay. And maybe even me. I mean, under the circumstances, why not enjoy the final show?

[Ron-Astro Pharmacist]

Today's superlative image is a sight us Northerners have to travel far to witness in person. I like the contrast of the dark horizon and bright sky. But as Art pointed out - not all constellations are experienced alike by all individuals.

Just as the stars of the Southern Cross can be made to stand out, I'd like to see the night sky transposed by some a creative photoshopper to show only distance groupings. By that I mean a sky of the most interactive stars or galaxy clusters.

Once the background stars were removed, the sky would have quite a different look - seeing those stars or galaxies that are truly related to each other. Barring a supernova, there may be an "app" for that but until then it's great to see something I can't. Where the ancient mariners saw crosses, I wonder what a new age astrographer might see. Constellation "Bart" ?

[donlauder]

The Southern Cross is also depicted on the National Flag of NEW ZEALAND.

[RJN]

The Australian flag does include the Southern Cross among its seven stars. The very similar New Zealand flag features only the four stars of the Southern Cross.

OK OK! The text has now been updated to include New Zealand. Apologies!

- RJN

[neufer]

Where the ancient mariners saw crosses, I wonder what a new age astrographer might see. Constellation "Bart" ?

• Bart already has a Comet named for him.

Bart's Comet

<<After Bart sabotages Principal Skinner's weather balloon, Skinner decides to punish him by having him help with his amateur astronomy. Skinner dreams of finding something in the sky and having it named after him. Bart accidentally locates a comet which is named after him.
.......................................................................

[b][color=#0000FF][size=150]The Three Wise Men[/size][/color][/b]

---

SKINNER: You don't need a telescope to enjoy astronomy, Bart. (pointing) There are all the constellations you've heard so much about. There's Orion, the swan, the chariot race...

BART: Why don't they look anything like their names?

SKINNER: Well, you do have to use your imagination. Look, there's the three wise men.

BART: Who names these things anyway?

SKINNER: Whoever discovers them. I've been hoping I could find something that would be named after me.

BART: And you've never found anything?

SKINNER: Once. But by the time I got to the phone, my discovery had already been reported by Principal Kahoutek. I got back at him, though... him and that little boy of his.
.......................................................................
Scientists soon discover that the comet is heading straight for Springfield. Professor Frink plans to launch a missile at the comet, dispelling everyone's fears. However, the missile flies past the comet, instead blowing up the only bridge out of town, dooming the people.

After seeing an issue of Time magazine, which presented the threat of comets hitting Earth on its cover, the writing staff decided to have an episode based on the concept of a comet hitting Springfield. They fleshed out the episode's plot over several days and John Swartzwelder then set about writing the details of the script.

Kent Brockman's list of gay people is composed of the show's production staff, who had to sign legal agreements that they would not sue their own show. As a result, according to Groening, many of the staff appear on lists of gay people on the Internet. The episodes marks the first appearance of Database, a character show creator Matt Groening dislikes if he is used for anything more than one line.>>

[Ron-Astro Pharmacist]

Where the ancient mariners saw crosses, I wonder what a new age astrographer might see. Constellation "Bart" ?

• Bart already has a Comet named for him.

Bart's Comet

<<After Bart sabotages Principal Skinner's weather balloon, Skinner decides to punish him by having him help with his amateur astronomy. Skinner dreams of finding something in the sky and having it named after him. Bart accidentally locates a comet which is named after him.
.......................................................................

[b][color=#0000FF][size=150]The Three Wise Men[/size][/color][/b]

---

SKINNER: You don't need a telescope to enjoy astronomy, Bart. (pointing) There are all the constellations you've heard so much about. There's Orion, the swan, the chariot race...

BART: Why don't they look anything like their names?

SKINNER: Well, you do have to use your imagination. Look, there's the three wise men.

BART: Who names these things anyway?

SKINNER: Whoever discovers them. I've been hoping I could find something that would be named after me.

BART: And you've never found anything?

SKINNER: Once. But by the time I got to the phone, my discovery had already been reported by Principal Kahoutek. I got back at him, though... him and that little boy of his.
.......................................................................
Scientists soon discover that the comet is heading straight for Springfield. Professor Frink plans to launch a missile at the comet, dispelling everyone's fears. However, the missile flies past the comet, instead blowing up the only bridge out of town, dooming the people.

After seeing an issue of Time magazine, which presented the threat of comets hitting Earth on its cover, the writing staff decided to have an episode based on the concept of a comet hitting Springfield. They fleshed out the episode's plot over several days and John Swartzwelder then set about writing the details of the script.

Kent Brockman's list of gay people is composed of the show's production staff, who had to sign legal agreements that they would not sue their own show. As a result, according to Groening, many of the staff appear on lists of gay people on the Internet. The episodes marks the first appearance of Database, a character show creator Matt Groening dislikes if he is used for anything more than one line.>>

Do you think Springfield Heights has an on-line degree available? Sounds like the place for my BS in physics.

[neufer]

Do you think [Springfield Heights Institute of Technology] has an on-line degree available?

Sounds like the place for my BS in physics.

• You were Principal Kahoutek's mischievous little boy weren't you.

[b][color=#0000FF]Barn[y]ard's star lies somewhere inside the boundaries of Taurus Poniatovii[/color][/b]

---

<<Taurus Poniatovii (Latin for Poniatowski's bull) was a constellation created by Marcin Odlanicki Poczobutt in 1777 to honor Stanislaus Poniatowski, king of Poland. It consisted of stars that are today considered part of Ophiuchus and Aquila. It is no longer in use. It was wedged in between Ophiuchus, Aquila and Serpens Cauda.

The stars were picked for the resemblance of their arrangement to the Hyades group which form the "head" of Taurus. Before the definition of Taurus Poniatovii, some of these had been part of the obsolete constellation River Tigris.

The brightest of these stars is 72 Oph (3.7 magnitude) in the "horn" of Taurus Poniatovii. The "face" of Taurus Poniatovii is formed by 67 Oph (4.0), 68 Oph (4.4) and 70 Oph (4.0). The five brightest stars belong to loose open cluster Collinder 359 or Melotte 186. Barnard's star is also inside the boundaries of this former constellation. Some minor stars (5th and 6th magnitude) now in Aquila formed the "rear" of Taurus Poniatovii.>>

[SteveInNZ]

OK OK! The text has now been updated to include New Zealand. Apologies!
- RJN

In the spirit of "you just can't win", New Zealand voters are about hold a referendum to select a possible replacement flag. Only two of the five new flag contenders include the Southern Cross.

Steve.

[Ron-Astro Pharmacist]

Do you think [Springfield Heights Institute of Technology] has an on-line degree available?

Sounds like the place for my BS in physics.

• You were Principal Kahoutek's mischievous little boy weren't you.

They say time runs faster has you get older. In my case I think the clock has a different problem. Not at all a sad story. Sort of like living in anti-time and you can't quite remember what's supposed to happen. So you wing it.