NGC 4236 is a tenth magnitude barred spiral galaxy in Draco that's visible through small telescopes although best seen with larger instruments. This galaxy was discovered by German born British astronomer William Herschel on April 6, 1793 and is a member of the Ursa Major or M81 group of galaxies that contains at least 34 galaxies, including spectacular M81 (Bode's galaxy) and M82 (Cigar galaxy).
NGC 4236 is located in the far northern constellation of Draco about 15 degrees north of the seven stars that form the famous "Plough" or "Big Dipper" asterism of Ursa Major. The galaxy is positioned two-thirds of the way along an imaginary line connecting stars lambda Dra (λ Dra - mag. +3.8) and kappa Dra (κ Dra - mag. +3.9). Star HD 106574 (mag +5.7) is 0.75 degrees directly north of NGC 4236.
Due to its high northerly declination, NGC 4236 is a Northern Hemisphere object. The best months to look for it are March, April or May, although from most northern locations it's visible all year round and never sets. It can be seen from the Southern Hemisphere, but only from latitudes north of 20 degrees south and even then appears low down above the northern horizon at best.
At apparent magnitude +9.7, NGC 4236 is a tough galaxy for small scopes but rewarding if you can catch it. An 80mm (3.1-inch) refractor reveals a thin needle haze of light that's best seen at low powers using averted vision. Through a 200mm (8-inch) scope the galaxy appears large and faint, but with a brighter centre that hints at mottling. Since it spans in total 22 x 7 arc minutes and not far from edge-on, NGC 4236 appears noticeable thin. In larger size amateur scopes, the galaxy shows much mottling and knotty details along its length with a slightly brighter oval shaped centre providing a pleasant view.
NGC 4236 is located 11.7 Million light-years distant. It has a radius of 75,000 light-years and is estimated to contain more than 100 billion stars. The galaxy is object number 3 in the Caldwell catalogue.
NGC 4236 Data Table
|Object Type||Barred Spiral Galaxy|
|Distance (light-years)||11.7 Million|
|RA (J2000)||12h 16m 42s|
|DEC (J2000)||69h 27m 45s|
|Apparent Size (arc mins)||22 x 7|
|Number of Stars||>100 Billion|
|Notable Feature||Member of the M81 Group|