The international astronomical union defines a constellation by its

area on the celestial sphere and its boundaries. A constellation is essentially a specific region of the sky that contains a group of stars. The boundaries of a constellation are determined by the IAU, and they are used to organize the night sky into recognizable patterns. This allows astronomers and others to easily locate and identify specific celestial objects, such as stars, planets, and deep sky objects, within a particular constellation.

The International Astronomical Union (IAU) defines a constellation by its boundaries, which are determined based on the positions of stars in the sky. These boundaries form a specific pattern or shape that represents a constellation. However, it is important to note that the IAU only recognizes 88 official constellations, each with its own specific boundaries.

To determine the boundaries of a constellation, one would typically require an astronomy software or a star chart. Here's how you can use a star chart or software to find the boundaries of a constellation:

1. Start by obtaining a star chart, which is a map of the night sky. It displays the positions of stars, constellations, and other celestial objects.
2. Choose a date and time for which you want to locate the constellation.
3. Identify the constellation you are interested in. Each constellation has a unique pattern of stars that form its shape.
4. Look for the major stars within the constellation and use them as reference points.
5. Connect the dots between the major stars to trace the outline of the constellation. This will give you a rough idea of the boundary.
6. Some star charts or software may also provide more precise boundary lines for the constellation.

It's worth noting that the boundaries of a constellation are somewhat arbitrary and can vary depending on cultural and historical interpretations. The IAU's official boundaries are the most widely recognized and accepted in modern astronomy.

The International Astronomical Union (IAU) defines a constellation based on its boundaries on the celestial sphere. A constellation is a specific area of the sky that has been divided into 88 sections, each representing a different constellation. These boundaries are fixed and agreed upon by the IAU, which is an organization responsible for the classification and nomenclature of celestial objects.