ε Pegasi

Epsilon Pegasi is Enif, ‘the nose’, an irregular variable supergiant with a usual magnitude of about 2.4 but which may brighten up to around 0.7 or dim to about 3.5. At a usual magnitude of 2.4 it's the brightest star in the constellation.

The star is roughly midway between two alphas: east of Altair (tip of the Summer Triangle) and west of alpha Pegasi: binoculars.

Northwest of epsilon, in the same field of view, is M15, a very bright globular cluster of well over 100,000 stars.With an apparent magnitude of 6.2, it could just be visible to the naked eye under perfect conditions; it's nicely seen in binoculars and spectacular in telescopes.

With an estimated age of 12 billion years, it's one of the oldest clusters known. The cluster has experienced a core collapse sometime in the past, resulting in an extremely dense core; in fact there may be a black hold in its centre.


One binocular field below epsilon is 3 Pegasi, a binocular binary (Struve I 56)AB: 6.2, 7.5; 347º, 39.1".

A little over two binocular fields west-southwest, just past theta Pegasi, is a group of numbered stars: binoculars.

Two among these are 30 Pegasi and 37 Pegasi; both are challenges for different reasons:
      30 Pegasi (h 962), with two very faint companions:
         AB: 5.4, 11.5; 17º, 6.4".
         AC: 5.4, 11.3; 228º, 18.0".
      37 Pegasi (Struve 2912), two white stars: 5.7, 7.1; 117º, 1.0" with an orbit of 140 years. It is presently about to dip under 1" separation, becoming extremely close to the primary over the next 20 years.

With 30 Pegasi on your southeastern edge, move one binocular field northwest: 20 Pegasi and two neighbours come into view as well as another fine binary, Struve 2857: 7.1, 9.8; 112º, 20.1"


Regain epsilon Pegasi (or if you have postponed visiting these binaries for another time and are still at epsilon), three full binocular fields due north brings you to kappa Pegasi.

Kappa Pegasi is a noted binary (BU 989)AB of two nearly equal stars: 4.9, 5.0; 281º, 0.2" with an extremely fast orbit of 11.52 years.
     There is a second component here, Struve 2824: AB-C: 4.9, 10.8; 288º, 14.5".


Centring kappa, move a little more than one binocular field south to 9 Pegasi, the brightest star in this field at 4.3 visual magnitude; it should be near the southern rim of your field of view. To the immediate east is the fainter 13 Pegasi.
     Look north from 13 Pegasi 2.5º and you will encounter a tight little group of three bright stars. The eastern-most of these three is a lovely binary Struve 2841, an orange-yellow primary and greenish companion, A-BC: 6.5, 8.0; 110º, 22.3".
     The western star in this trio is also quite bright (it's a multiple system as well but with very faint companions). Making a small right triangle with these two bright stars to the south is Struve 2834, an interesting multiple system, as the components are exactly 180º from each other:
     Struve 2834AB: 6.9, 9.9; 298º, 4.1".
     AC: 6.9, 12.6; 118º, 29.6".

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