... М102 < М103 > М104 ...

Open star cluster M103

Open star cluster M103 is in the constellation Cassiopeia (Cas).

Equatorial coordinates (epoch J2000):
Ra (α):01^h33.2^m, Dec (δ):+60° 42'

Visual magnitude: 7,0^m
Distance from the star clusters M103 to the Sun is 7150 light years
Angular size: 6'
Class: d
External dimensions the star clusters M103 are about 17 light years.
Number of stars: 77
Age of the object M103 is 16—25x10⁶ years

Discoverer: Pierre François André Méchain, 1781 year.

The designation M103 in other catalogs: NGC 581

Optimum magnification for a telescope with observations of M103, depending on the aperture of the telescope (D), is about 20x. Higher magnifications of course add details, but lead to a strong drop in the brightness of the image, making it difficult to observe.

The best month for observing M103 is October. At this time, the object is at midnight near its highest point in the sky, that is, it is less affected by light from the lanterns and atmospheric distortions.

Мessier 102

Мessier 104

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