Use the Stamy Night Enthusiast \({ }^{\mathrm{TM}}\) program to observe other galaxies. Select Favourites \(>\) Guides \(>\) Atlas to display the entire celestial sphere. Open the Options pane, expand the Deep Space list, and click the box for Messier Objects to display these objects. Open the Find pane and select each of the following galaxies in turn. Zoom in as necessary to see the shape of the galaxy to determine its Hubble classification as well as you can, and explain your reasoning: (i) Virgo A (M87); (ii) M105; (iii) \(\mathrm{M} 102\); (iv) M104; (v) M109.

Messier Objects are a set of astronomical objects cataloged by the French astronomer Charles Messier in the 18th century. This catalog, known as the Messier Catalogue, includes some of the most fascinating and well-known objects observable from Earth, such as galaxies, nebulae, and star clusters.

Originally, Messier was a comet hunter and compiled this list to avoid mistaking these permanent objects for comets. The catalog, which started with 45 objects, expanded to include 110 objects and is still widely used by amateur astronomers as a guide to the night sky. The objects are designated by an 'M' followed by a number, hence names like M87 for the Virgo A galaxy.

Messier Objects are favorites for observational assignments because they are bright enough to be seen through small telescopes or binoculars, making them accessible even to novice astronomers.

Galaxy observation involves the study of galaxies' structure, composition, and behavior using various astronomical tools. With advancements in technology, even amateur astronomers can observe distant galaxies and attempt to classify them based on their appearances.

A crucial aspect of galaxy observation is noting the shape, size, central brightness, and the presence of arms or bars which can help in categorizing galaxies according to the Hubble classification. This classification system categorizes galaxies into broad classes such as elliptical, spiral, barred spiral, and irregular. These characteristics provide clues about the galaxy's history, its stellar populations, and its evolutionary stage. Successful observation also requires clear skies and, ideally, areas with minimal light pollution.

Astronomy software, such as the Stamy Night Enthusiast program mentioned in the exercise, has revolutionized the way we observe and study the night sky. These sophisticated programs allow users to simulate the celestial sphere on their computers, offering features like zooming in on galaxies, overlaying constellation patterns, and identifying objects in real time.

The use of astronomy software is instrumental in educational settings. It aids in understanding the cosmos without the need for expensive equipment. By choosing certain settings, users can display specific objects like Messier Objects, planets, and other celestial phenomena. The software often includes databases with detailed information about these objects, making it a valuable tool for both amateur and professional astronomers.

The celestial sphere is an abstract, imaginary sphere of an arbitrarily large radius, centered on the observer. It is used in astronomy to describe the apparent positions of the stars, planets, and other celestial objects. As the Earth rotates and orbits around the Sun, the celestial sphere appears to rotate, bringing different parts into view at different times of the year.

Software programs like Stamy Night Enthusiast represent the celestial sphere to allow users to navigate the sky as it appears from Earth. Learning to navigate the celestial sphere is essential for astronomy enthusiasts, as it helps in locating and identifying various celestial objects. It's a fundamental concept that helps bridge the gap between our terrestrial perspective and the expansive universe that surrounds us.