- Alpha Cassiopeiae or α Cassiopeiae, also named Schedar (/ˈʃɛdɑːr/), is a second-magnitude star in the northern constellation of Cassiopeia. Though listed as the “alpha star” by Johann Bayer, α Cas’s visual brightness closely matches the ‘beta’ (β) star in the constellation (Beta Cassiopeiae) and it may appear marginally brighter or dimmer, depending on which passband is used. However, recent calculations from NASA’s WISE telescope confirm that α Cas is the brightest in Cassiopeia, with an apparent magnitude of 2.240. Its absolute magnitude is 18 times greater than β Cas, and it is located over four times farther away from the Sun.
- Messier 4 (Wikipedia)
Messier 4 or M4 (also known as NGC 6121 or the Spider Globular Cluster) is a globular cluster in the constellation of Scorpius. It was discovered by Philippe Loys de Chéseaux in 1745 and catalogued by Charles Messier in 1764. It was the first globular cluster in which individual stars were resolved.