M97 or "the Owl Nebula" is a famous planetary nebula located in the constellation of Ursa Major. It was discovered by Pierre Mechain on February 16, 1781 and is one of only four planetary nebulae listed in the Messier catalogue. The name Owl Nebula was first coined by William Parsons, 3rd Earl of Rosse who noticed owl-like "eyes" when observing the nebula in 1848. At magnitude +9.9, it's not particularly bright but is spectacular and regarded as one of the more complex examples of its type.
Locating M97 is easy; it's positioned only 2.5 degrees southeast of bright star Merak (β UMa - mag. +2.3), which forms the southwest corner of the bowl of the famous Plough or Big Dipper asterism of Ursa Major. In the same wide field telescope field of view, 50 arc minutes northwest of M97 is the barred spiral galaxy M108 (mag. +10.2).
The Owl Nebula is best seen from Northern Hemisphere latitudes during the months of March, April and May. From latitudes north of 35N it's circumpolar and therefore never sets.
Due to its low surface brightness the Owl Nebula is a challenging object for large binoculars and small telescope observers. It's visible in 20x80 binoculars and 100mm (4-inch) scopes but usually requires very dark skies and excellent observing conditions to be seen. It appears as nothing more than a dim circular disk or fuzzy ball without detail.
The famous eyes consist of two dark patches superimposed on the face of the nebula. Under good conditions a 200mm (8-inch) scope at high power can show the eyes, but normally a 250mm (10-inch) scope is required to see them. An ultra high contrast deep sky or light pollution filter may also help. M97's central star is of only 14th magnitude making it an elusive target in anything less than a 350mm (14-inch) telescope.
M97 has an apparent size of 3.4 x 3.3 arc minutes. At a distance of 2,600 light-years form Earth this equates to an actual diameter of 3 light-years. It's a fantastic deep sky object that's estimated to be 8,000 years old. Although not that bright, it's a worthy object on any observing list.
M97 Data Table
|Object Type||Planetary nebula|
|RA (J2000)||11h 14m 48s|
|DEC (J2000)||55d 01m 07s|
|Apparent Size (arc mins)||3.4 x 3.3|
|Notable Feature||Owl like "eyes" visible through larger amateur telescopes.|