Thread: Idea for story, check its plausibility por favor

So here's the spiel - I'm taking an astronomy class at the moment, so now I'm just a wee bit wiser to this sort of thing, but it'd still be interesting to enact...if I can. I just wanna see if it's really a practical plot device, or if it would, in reality, backfire.

Basically, I'd like to write a story wherein the main character - who is from Earth - finds himself on an alien world. At some point, he'll look up at the sky and see the asterism known as the Big Dipper, only it's a mirror image of the way it naturally faces when viewed from Earth...meaning that this world is located in a star system beyond the Big Dipper. This would help him pinpoint (somewhat) where he is so that the people of that world can help him find his way back to Earth.

But to be realistic, I'd need to take into consideration the distance between our own Sun and the 7 stars that make up the Big Dipper. Even though most of those stars appear to be the same brightness to us, some of them are further away, meaning they're even brighter than they appear. So on the other side of the asterism, those stars would be closer to this world - and thus brighter than they appear from on Earth - which makes me think that viewing the Big Dipper from the "other side" could make a radically different-looking asterism. Or if not radically different, at least different enough not to be noticed.

I'm really quite lousy at calculating this sort of thing, so I can't get a straight answer for myself on exactly how bright each star would appear on this strange planet X.

I was also gonna incorporate Polaris somehow, but that's about 4 times further away from Earth than the furthest Big Dipper star.

In short, just let me know if this story is sounding plausible, or if it's looking grim by this point. If you actually care to calculate the apparent magnitude of those stars for me, I'll give you infinite internet cookies, but I don't really expect that.

If the Big Dipper doesn't work, I was looking at Crux (Southern Cross) as an alternative asterism, which might even work better considering there's an obvious red star among them...