No I'm talking about the constellation, not the M31 galaxy. why does the constellation always look different

Question

...depending on the book or website youre looking at. on one diagram it might have 8 stars in it, while on another diagram have more and look completely different. is there total agreement about exactly which stars make up the constellation?

Answer 1

There are no official stick figures for the constellations. Old star maps used full pictorial representations; the stick figures seem to be a more modern way of indicating constellations. The International Astronomical Union (IAU) has defined boundaries dividing the entire sky into 88 constellations. All the stars within the boundaries defined for Andromeda are considered to be within the constellation, but which ones are part of the figure is up to the illustrator. Some stars, such as β Andromedae, called Mirach, the girdle, have names which suggest their position within the constellation figure.

Answer 2

I've see it done as a V or an F or an h.


I like the unspiraling curving V better though, I think it looks better.
Personal opinion.

Even though the end star completes the Great Square of Pegasus, it is officially Andromedan. They had to chose something.


And as for the complete number of stars, pattern or otherwise, it depends on how deep the star map goes. You could have this whole sky map which shows only a few stars, or this huge sky atlas with many hundreds and hundreds of stars, and they're all correct since anything inside the boundries is Andromedan, one just shows dimmer stars than others.

This is like a map where Andromeda is a country, they can show as many or as few cities (stars) as they want, and the patterns are like airline routes connecting only the major cities (the main stars of the constellation)
Different airlines (stellar mapmakers) can connect the country's major cities (main stars) anyway they want, like airline routes, it's not official, only the boundries are set in stone
Some airlines (the mapdrawers) might not even think star X is important enough to be part of the loop, so in their view it's just like any of the other minor towns and cities in the country (constellations)
This explains the many non-pattern stars.

Just like wouldn't say Smuckersville, NH is not in the USA because it has no airline service, then you wouldn't say this small star HP 1223 isn't inside it's own constellation just because it's not connected by lines.

Andromeda has few bright stars, and looks nothing like what it's supposed to be (a woman), so probably explaining the many representations.

Answer 3

It means that distant galaxy (which appears very small at the vast distance) can be found by looking within the boundaries of a constellation. It doesn't mean that galaxy is actually in the constellation, it means that galaxy appears in the sky in the same area as the constellation (but of course at much greater distances than any of the stars that make up the constellation). Its a convenient way to locate and identify distant objects.

Answer 4

Constellations are only pretty pictures joining bright stars. There is no absolute definitions on where the boundary between one constellation and another are, it is all arbitrary. And astronomers will not lose time defining such boundaries because it does not add anything to their work, as most stars are located through their position -- right ascension and declination -- anyway.
Therefore any reference you may have will be the result of "artistic" decision on the part of the author of said reference as to where the boundaries are.

Answer 5

What constellation are you talking about?

Answer 6

If you post some links of these different maps it will help to get you an answer.