Discovering Earth's View from Epsilon Indi: Answers by Chinspinner

[Chinspinner]

Hi,

I wonder if anyone can answer the following: -

What constellation would our sun appear in if viewed from Epsilon Indi?

Thanks in advance

Chinspinner

 

[Vanadium 50]

Epsilon Indii would not have the same constellations we do. However, the sun would be in the general direction of Ursa Major.

 

[Chinspinner]

Excellent. Thanks very much.

 

[chasrob]

Here's the view from epsilon Indi from the astronexus page-looks like you just extend a line from the bottom of the cup of the big dipper (which looks the same as from earth).

 

[Chinspinner]

That is brilliant, thanks Chasrob.

 

[chasrob]

Here's a less cluttered version-as Vanadium said it's in Ursa Major; other stars have moved, like Arcturus and alpha Centauri...

 

[snorkack]

Epsilon Indii would not have the same constellations we do. However, the sun would be in the general direction of Ursa Major.

And Big Dipper is still there.
Out of 21 brightest stars in sky, brighter than +1,4 on Sun, 11 are closer than 100 lightyears, and 10 are remoter. Of the next 26 (+1,4 to +1,99), 4 are.

Regarding the Big Dipper, most of it is an open cluster, meaning the stars stay together when viewing it from a different nearby point of view. The stars that stand out are the stars at the ends - Alkaid and Dubhe - which are behind the rest, at 101 and 124 lightyears respectively, and Megrez in the middle which is in front, at 58 lightyears. The other four are all between 78 and 84 lightyears of Sun. So moving away from Big Dipper, towards Indus, produces little distortion... only slight dimming and shrinking.

 

[Vanadium 50]

Yes, the Big Dipper asterism persists. (One might argue that sol makes an eighth star, but I expect it's dimmer than Megrez) Some will - particularly those with the stars far away - and some won't. For example, Gemini's Castor and Pollux are relatively unchanged, but are now joined by Procyon (now in Gemini, or possibly Cancer) and Sirius has left Canis Major and joined Canis Minor.

 

[snorkack]

Yes, the Big Dipper asterism persists. (One might argue that sol makes an eighth star, but I expect it's dimmer than Megrez)

No.
Sun is about +2,8. Megrez will have faded from the +3,31 on Sun to +3,7. Merak and Phecda, having faded from about +2,4 to +2,7 are only slightly brighter than Sun; Dubhe only fades from the +1,79 to +2,0.
So what does that extra star make Dipper into?

Some will - particularly those with the stars far away - and some won't. For example, Gemini's Castor and Pollux are relatively unchanged, but are now joined by Procyon (now in Gemini, or possibly Cancer) and Sirius has left Canis Major and joined Canis Minor.

As for Indus itself, Epsilon at +4,69 is the sixth brightest star. The brighter five are all further than 97 lightyears. (but not so much brighter, so Epsilon will be missed)
In Ursa Major, the stars to the foreground of Dipper (that shrink towards Dipper and fade) include
Talitha Borealis (48 ly, +3,12)
Al Haud (44 ly, +3,17)
Alula Australis (27 ly, +3,79)

 

[chasrob]

That page--http://[URL='http://www.astronexus.com/endeavour/chart']www.astronexus.com/endeavour/chart[/URL] -- is a lot of fun to play around with. Here's a zoom out with constellations added-

Castor and Pollux have moved slightly north into Lynx. Procyon and Sirius are in the northern reaches of Cancer, Arcturus has changed constellations. But the biggest move is alpha Centauri (here called Rigil Kentaurus). From the far south to the north in Ursa Major below the dipper. Maybe you pass it by on your way to epsilon Indi?

 

[snorkack]

Castor and Pollux have moved slightly north into Lynx. Procyon and Sirius are in the northern reaches of Cancer,

Sticking to the Earth constellation borders. Essentially, they make Twins into Quadruplets.

But the biggest move is alpha Centauri (here called Rigil Kentaurus).

Of course - it is the nearest star.

From the far south to the north in Ursa Major below the dipper. Maybe you pass it by on your way to epsilon Indi?

Probably yes!
The nearby sunlike stars are funnily clustered:
Rigil Kentaurus at 4,3 ly
Epsilon Eridani, 61 Cygni, Tau Ceti and Epsilon Indi all four between 10,5 and 11,9 ly
and then next Keid at 16,5 ly.

But how does the sky look like from Rigil Kentaurus? Specifically, where does Rigil Kentaurus AB orbit lie in Rigil Kentaurus sky?