This large constellation stands out mainly because of the three stars that make up the Square of Pegasus together with α Andromedae. Otherwise, the Pegasus contains few bright stars, and there are few interesting destinations even for a smaller telescope. When looking at Pegasus, we look out of the galactic plane, where the next galaxy is NGC 7331 at a distance of probably 45 million light-years.
β Pegasi is an orange star at a distance of 199 light-years. Its brightness varies slowly and at irregular intervals between 2.1 and 3.0m. You can use the other stars of the Square of Pegasus for comparison. It is also worthwhile to look at the colors of the stars – the 2.8m bright γ Pegasi appears bluish, while both the 2.5m bright α Pegasi and the 2.1m bright α Andromedae look more bluish white.
51 Pegasi is an inconspicuous, 50 light-years distant star, which is 1.3 times brighter than our Sun. At 5.5m, it is visible to the naked eye in good nights about halfway between α and β Pegasi, on the connecting line between α and μ Pegasi. It is unspectacular in the telescope, too. It became famous in 1995, when Michel Mayor and Didier Queloz from the Geneva Observatory were able to prove a planet in its orbit with half the mass of Jupiter – the first planet outside of our solar system. Slight changes in the position of the star provided an indication of a planet, which could be proven only by studying the spectrum of the star. The planet is only 4.4 million miles (7 million kilometers) away from the star and probably formed at a greater distance from it.
AG Pegasi is an irregular variable which you can find 3.5° northeast of ε Pegasi. Between 1850 and 1870 it increased its brightness from 9 to 6m, but from 1920 on, the brightness dropped again. Around the turn of the millennium it was about 8.7m. With the decrease in brightness also changes in the star‘s spectrum could be observed, including an increase in the titanium content. AG Pegasi belongs to the Z Andromedae stars. It is a close binary system consisting of a cool giant star and a white dwarf star. If gas moves from the giant star to the dwarf, it is heated. Because the mass transfer takes place irregularly, also the brightness of the system changes unpredictably. In addition, the brightness of the giant star varies.
M 15 is a 30,600 light-years distant globular cluster, which is in principle visible to the naked eye as a 6.2m bright patch of light 4° northwest of ε Pegasi. A pair of binoculars resolves two bright stars about 7.4m and 6.1m that frame a nebula with up to 15 minutes of arc diameter. Of course, the 160 light-years large globular cluster itself can‘t be resolved into stars in binoculars, and its most remarkable detail remains hidden – the only one arcsecond wide and 13.8m bright Pease 1 was for a long time the only known planetary nebula in a globular cluster. Meanwhile, another stellar corpse was also discovered in M 22 in Sagittarius.
NGC 7331 is the brightest galaxy in Pegasus and 40 to 65 million light-years away. At 10.3m, this spiral galaxy is not too obvious, but nevertheless it can be recognized as a faint, some arc minutes long stroke in binoculars. The galaxy is sometimes used as a basis for representations of our Milky Way. Several other galaxies in its vicinity remain invisible.