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View Full Version : Would I Identify Certain Constellations from "Somewhere Else"?



Fiery Phoenix
2009-Jun-13, 05:49 PM
For instance, if I were standing on the surface of, say, Mars, would I still see the same constellations that are normally seen from Earth? I'd personally say yes, since, astronomically speaking, Earth and Mars are more or less in the same location, although I'm not very sure.

My actual question would be: If I were standing on the surface of a planet orbiting Proxima Centauri and staring at the night sky, would I be able to identify at least some of the constellations that are known to us Earth people?

Maybe this is pretty basic stuff, but I'm sure many other people would like to see an explanation.

chornedsnorkack
2009-Jun-13, 06:05 PM
I believe yes.

Among the brightest stars, most are farther away than 100 lightyears. A minority of bright stars are closer - Toliman, Sirius, Procyon etc. etc. - but a lot are remote, e. g. Orion is mostly 500...2000 ly away.

Which other constellations consist of remote stars and therefore stay recognizable some distance away?

Fiery Phoenix
2009-Jun-13, 06:10 PM
Which other constellations consist of remote stars and therefore stay recognizable some distance away?

Nothing I can think of right now, but thanks for the quick reply. :)

PraedSt
2009-Jun-13, 06:18 PM
Is Proxima Centauri a part of any constellation?

Of course the nice thing is that you could make up a new constellation; one with our Sun in it. :)

Fiery Phoenix
2009-Jun-13, 06:25 PM
Is Proxima Centauri a part of any constellation?

Yes, Centaurus. :)


Of course the nice thing is that you could make up a new constellation; one with our Sun in it. :)

Oh yeah, haha! I actually remember Carl Sagan saying something about which constellation the Sun would appear to be in from Alpha Centauri (or Proxima Centaur, for that matter). I just can't remember the name of the constellation; sorry. ><"

PraedSt
2009-Jun-13, 06:39 PM
Yes, Centaurus.Oh boy. Classic noob. :doh:



Oh yeah, haha! I actually remember Carl Sagan saying something about which constellation the Sun would appear to be in from Alpha Centauri (or Proxima Centaur, for that matter). I just can't remember the name of the constellation; sorry. ><"At the risk of another clanger, that should be easy to work out, right? It'll be the constellation that's "opposite" to Centaurus?

Fiery Phoenix
2009-Jun-13, 06:45 PM
At the risk of another clanger, that should be easy to work out, right? It'll be the constellation that's "opposite" to Centaurus?

And which constellation would that be? I have no clue myself.

matthewota
2009-Jun-13, 06:46 PM
Yes to both questions. This subject was covered by a Chris Butler lecture at a meeting of the Orange Co. Astronomers a couple of years ago. He did it all with software.

chornedsnorkack
2009-Jun-13, 06:46 PM
Oh yeah, haha! I actually remember Carl Sagan saying something about which constellation the Sun would appear to be in from Alpha Centauri (or Proxima Centaur, for that matter). I just can't remember the name of the constellation; sorry. ><"

Cassiopeia.

Sun is about magnitude +0,5.

The brightest stars of Cassiopeia from Sun? Tsih (Gamma) is +2,15, at 613 ly. Schedar (Alpha) is +2,24, at 228 ly. Caph (Beta) is +2,28, at 54 ly. Ruchbah (Delta) is +2,66, at 99 ly. Segin (Epsilon) is already +3,35.

Achird (Eta) is +3,46, and is notable for being very close, at 19 ly from Sun.

Note that moving directly into or out of a constellation would not distort a constellation so grossly as parallax on sidewards displacement....

PraedSt
2009-Jun-13, 06:53 PM
Cassiopeia.

Sun is about magnitude +0,5.

The brightest stars of Cassiopeia from Sun? Tsih (Gamma) is +2,15, at 613 ly. Schedar (Alpha) is +2,24, at 228 ly. Caph (Beta) is +2,28, at 54 ly. Ruchbah (Delta) is +2,66, at 99 ly. Segin (Epsilon) is already +3,35.

Achird (Eta) is +3,46, and is notable for being very close, at 19 ly from Sun.

Note that moving directly into or out of a constellation would not distort a constellation so grossly as parallax on sidewards displacement....
Wow. Impressive knowledge. I had to use this sky map site (http://www.fourmilab.ch/cgi-bin/Yourtel). Centaurus is 13h, -50; so I looked up 1h, 50. Cassiopeia. Nice to get conformation that I'm not a total noob. :)

Fiery Phoenix
2009-Jun-13, 06:57 PM
Cassiopeia.

Sun is about magnitude +0,5.

The brightest stars of Cassiopeia from Sun? Tsih (Gamma) is +2,15, at 613 ly. Schedar (Alpha) is +2,24, at 228 ly. Caph (Beta) is +2,28, at 54 ly. Ruchbah (Delta) is +2,66, at 99 ly. Segin (Epsilon) is already +3,35.

Achird (Eta) is +3,46, and is notable for being very close, at 19 ly from Sun.

Note that moving directly into or out of a constellation would not distort a constellation so grossly as parallax on sidewards displacement....

That's it! And thanks for your interesting post, sir.:)

grant hutchison
2009-Jun-13, 07:02 PM
This is a nice use for Celestia (http://www.shatters.net/celestia/). Turn on the constellation diagrams, and fly around the local stars, observing how much the constellations distort.
You get prompt distortion of constellations that contain bright nearby stars: Canis Major, Canis Minor and Centaurus, for instance. But little distortion of constellations containing only distant bright stars: Orion and Ursa Major, for instance.
In the particular case of Proxima, the Centaurus constellation obviously gets knocked out of shape quite dramatically. Sirius leaves Canis Major and ends up under Orion's armpit, close to Betelgeuse. Procyon abandons Canis Minor and moves into the middle of Gemini.

Grant Hutchison

chornedsnorkack
2009-Jun-13, 07:08 PM
Wow. Impressive knowledge. I had to use this sky map site (http://www.fourmilab.ch/cgi-bin/Yourtel).
Well, I found and summarized this:
http://en.wikipedia.org/wiki/List_of_stars_in_Cassiopeia

pumpkinpie
2009-Jun-13, 07:52 PM
I recommend you check out Celestia, as grant hutchinson recommended. It is a great way to visually understand the spacial distribution of stars.

I use a program in my planetarium that does what Celestia does. When I go to my office this weekend or Monday I can try to do a "screen shot" of what the stars look like as seen from Proxima.

KaiYeves
2009-Jun-13, 09:00 PM
Oh yeah, haha! I actually remember Carl Sagan saying something about which constellation the Sun would appear to be in from Alpha Centauri (or Proxima Centaur, for that matter). I just can't remember the name of the constellation; sorry. ><"
It's in Cassiopeia, and he imagined it as looking like a unicorn.

pumpkinpie
2009-Jun-15, 05:51 PM
Here is the screen shot I was talking about. Proxima is in the foreground, and we're looking toward the Sun. You can see the constellations in that direction are rather familiar!
The red line coming from the top of the screen is part of Centaurus so the stars at the end are Alpha and Beta.

If it isn't clear let me know and I can tweak it a bit.

PraedSt
2009-Jun-15, 06:13 PM
From that and my skymap website, it looks like the Sun will fall in the middle of Cassiopeia, Perseus and Andromeda. Is that right?

grant hutchison
2009-Jun-15, 06:53 PM
From that and my skymap website, it looks like the Sun will fall in the middle of Cassiopeia, Perseus and Andromeda. Is that right?It's in the Perseus/Camelopardalis corner of Cassiopeia. It adds an extra zag to the zig-zag of Cassiopeia, at the Eta Cas end.

Grant Hutchison

PraedSt
2009-Jun-15, 07:45 PM
Ah, ok. More towards Camelopardalis, and away from Andromeda. Thanks.

grant hutchison
2009-Jun-15, 09:37 PM
Ah, ok. More towards Camelopardalis, and away from Andromeda. Thanks.Picture (http://www.ghutchison.pwp.blueyonder.co.uk/cassiopeia.jpg). From Celestia.

Grant Hutchison

PraedSt
2009-Jun-15, 10:03 PM
Picture (http://www.ghutchison.pwp.blueyonder.co.uk/cassiopeia.jpg). From Celestia.

Grant Hutchison
You've convinced me. I'm downloading the software.

Fiery Phoenix
2009-Jun-16, 07:25 AM
Very interesting stuff, Grant! If only people would turn from their stress and ponder such things for a short while...

Many thanks for the picture.

grant hutchison
2009-Jun-16, 09:33 AM
Many thanks for the picture.Doesn't look much like a unicorn, does it? :)
I think KaiYeves is misremembering (http://www.bautforum.com/1508453-post15.html), partially. Carl Sagan wrote about the position of the Sun in Casseopeia when viewed from Alpha Centauri, but then went on to talk about the view from Tau Ceti. He and his wife invented a constellation for Tau Ceti's sky: a six-legged unicorn with the sun ignominiously positioned "... at the point where the unicorn's tail joins the rest of his body." (See the first chapter of his 1973 book The Cosmic Connection.)

Grant Hutchison

KaiYeves
2009-Jun-17, 01:03 AM
Unless I'm misremembering again, that chapter was the second in the book.

grant hutchison
2009-Jun-17, 08:49 PM
Unless I'm misremembering again, that chapter was the second in the book.No, you're quite right: my mistake. :doh:Chapter 2 is entitled The Unicorn of Cetus. Since his sky maps start on page 10 of my copy, I assumed I must still be in the first chapter.

Grant Hutchison

Paul Beardsley
2009-Jun-17, 08:57 PM
So which would be stranger - to inexplicably wake up on a planet on the other side of the galaxy where everything is different, or to wake up on the planet of a nearby star where most of the sky is familiar but with jarring little differences?