... М39 < М40 > М41 ...

Optical pair of stars M40

Optical pair of stars M40 or Winnecke 4 is in the constellation Ursa Major (UMa).

Equatorial coordinates (epoch J2000):
Ra (α):12^h22.2^m, Dec (δ):+58° 05'

Visual magnitude: 9^m
Angular size: 0,8'

Discoverer: Charles Messier, 1764 year.

The designation M40 in other catalogs: WNC 4

Optimum magnification for a telescope with observations of M40, depending on the aperture of the telescope (D), is about >10x. 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 M40 is April. 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 39

Мessier 41

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