NGC 2371 & NGC 2372 -- Planetary Nebula in Gemini
The Double Bubble
NGC 2371 and NGC 2372 make up a single Planetary Nebula. The two designations are
a result of this huge Planetary Nebula (one of the largest known) having two bright opposite
bright areas (lobes) in its shell. In an amateur-sized telescope, these bright lobes outshine
the nebula’s very-dim outer wings and only slightly brighter central star (14.8 magnitude).
Through the 155mm refractor from my suburban backyard, only the twin bright areas in the
shell show in the eyepiece. The view was greatly enhanced using a nebula filter. Stephen
O’Meara’s name for this Planetary Nebula is the “Double Bubble Nebula” which I feel is
equal to its other common name, “The Gemini Nebula”. I can live with either name.
Each of the twin bright lobes are about one light year across while the nebula’s full size is
approaching three light years across – this is huge for a bright planetary nebula. The
southwest lobe is distinctly brighter than the northeast lobe and both were not difficult in my
telescope using a nebula filter at 84x. I made the drawing at this magnification, but the
twin lobes really showed best at 182x. However, I settled on the lower power because it
provided a more pleasing view of the surrounding star field.