By engaging with all the videos within this series, you will effectively complete a full undergraduate course in astronomy, equipping yourself with the knowledge and skills necessary to navigate the night sky with confidence, learning all the basics and many advanced topics! I will embark on a journey through our galaxy, the Milky Way. We will commence by examining a visually striking spiral galaxy that closely resembles the Milky Way. As we delve into the realm of spiral galaxies, I will elucidate their fundamental structure. These galaxies consist of a central spheroidal region and a surrounding disk. At the heart of the galaxy lies the galactic core, encircled by a dense bulge and a halo of ancient, globular clusters. The disk extends outward, a thin plane brimming with stars, gas, and dust. The dark bands observed indicate dust clouds, while the bright red flares signify regions such as the Orion Nebula, which emit light due to young, hot stars. Next, we will zoom in on the disk and the spheroidal structure in exquisite detail. The disk, approximately 1,000 parsecs in thickness, harbors a diverse population of stars, comprising both young and old celestial bodies. Notably, we will observe open clusters and OB associations—regions characterized by an abundance of young stars. Conversely, the spheroid, commonly referred to as the halo, is predominantly populated by older stars, exhibiting a scarcity of gas and dust. Within the disk, we will observe a thin layer of gas and dust, primarily composed of atomic hydrogen. This layer emits 21-centimeter radiation, a captivating phenomenon resulting from energy transitions within hydrogen atoms. In contrast, we will also examine molecular hydrogen, which is traced with carbon monoxide, highlighting the narrow regions where star formation occurs. Subsequently, I will guide you through the captivating world of another Milky Way analog. This spiral galaxy, observed almost edge-on from approximately 49 million light-years away, exhibits dusty spiral arms and luminous regions of star formation. This observation provides us with a window into the processes transpiring within our own Milky Way, elucidating the interactions and evolution of stars and dust. Furthermore, we will take a historical detour to honor Walter Baade, a pioneering astronomer who made groundbreaking discoveries during World War II by utilizing the blackout conditions in Los Angeles. His work with the 100-inch telescope at Mount Wilson unveiled the presence of distinct stellar populations in the Andromeda Galaxy, a significant advancement in our comprehension of spiral galaxies. As we delve deeper into this subject, we will explore the various types of stellar populations, including Population I and Population II stars. Population I stars, predominantly found in the disk, exhibit metal-rich characteristics and are prevalent in regions undergoing active star formation. Conversely, Population II stars reside in the spheroid or halo region. Overall, the segment emphasizes clear definitions, underlying geometry, and practical observing guidance so viewers can connect the concept to the real sky.