Русский en en en en en en en en en en en en
... М90 < М91 > М92 ...

Spiral galaxy M91

Spiral galaxy M91 is in the constellation Coma Berenices (Com).


Equatorial coordinates (epoch J2000):
Ra 12h 35.4m, Dec +14° 30'

Visual magnitude: 10,1m
Distance to the galaxy M91 to the Sun is 52,9*106 light years
Angular size: 5'×4'
Class: SBb
External dimensions the galaxy M91 are about 83000 light years.

Discoverer: William Herschel, 08.04.1784 year.

The designation M91 in other catalogs: NGC 4548

Optimum magnification for a telescope with observations of M91, depending on the aperture of the telescope (D), is about D/6-D/3. 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 M91 is May.
For observers in the northern latitudes: the night sky in May is no longer very dark, so try also to observe M91 in April.
Of course, in April the object is at midnight not at its highest point, which provides the least exposure and atmospheric distortion. But, the darkness of the April sky greatly increases the contrast. The farther south the location of your observation is located, the darker the summer sky will be.

Nikolay Kurdyapin,  
Liked?   or tell your friends:

© 2018,
At a reprint of materials from this site link to the obligatory.