How to find NGC2139 from Mirzam

Identify the first reference star, then follow the numbered hops.

Follow the route from one recognizable star to the next until you reach NGC2139.

NGC2139 is 13° above the horizon toward the southeast.

Mirzam

Center Mirzam in the finder or a low-power eyepiece before following the field stars.

From Mirzam, move about 5.5° toward the southwest until you reach HYG 29150.0.

From HYG 29150.0, move about 2.2° toward the southwest until you reach NGC2139. This is the target field.