Constellations

[Stars in Their Eyes]

Being new to astronomy I've been reading several books and star charts and have found some differences in the constellations. For example, some will show Gemini with arms and some don't; some will show The great Bear with a head and some don't; some will show Orion will his bow and some don't.

Is there any reason for these irregularities, and has anyone else come across this before?

[The Warthog]

It is a matter of how the author of the chart learned the constellation, and perhaps some artistic license. The important thing is that all the stars are included in the constellation boundaries, and are named properly. The lines are not "official" but only a sort of device to help in identifying the constellation.

[hal2000]

It really depends upon what purpose the star chart serves. For instance, the monthly star chart in eg Astronomy Now, or in your local newspaper, just serves as a general guide, and will only show the brightest stars, which define the general position of the constellations, or, for example, an easily recognized asterism like the Plough in Ursa Major or the "W" in Cassiopeia.

On the other hand, a star atlas like the Cambridge or Norton's will show fainter stars, usually down to 6th magnitude, which is as faint as most people can see with the naked eye in a dark sky.

Those stars in the "arms" of Gemini, or in the Bow of Orion, are fainter than the main stars in their respective constellations, and will normally only be shown in an atlas.

[Barry W]

I know what you mean. The original constellations were defined by the ancients and have evolved into what what are the 88 officially recognized ones. In the process of defining the boundaries some stars have moved from one constellation to another. As far as the pictures are concerned, I don't think that anything is "officially" recognized. The pictures in the reference books you read, depend wholly on the author's/artist's preference. It's makes no difference to the constellations' make up. Hope this helps.

Cheers,

Barry