These are 5 position alpha-numeric codes comprising the d series. All other level II codes and descriptors are approved and maintained jointly by the alpha-numeric editorial panel (consisting of CMS, the Health Insurance Association of America, and the Blue Cross and Blue Shield Association).
Alaska: Although Alaska enjoys a high volume of aurora activity, its cruises are not often mentioned as northern lights cruises. During the Alaska cruise season, it's rarely dark enough for the lights to be visible.
Most Northern Lights-themed cruises sail to northern Norway, where the aurora appears regularly and the climate is relatively benign, or to Iceland. In 2016, four cruise lines will be operating trips (scroll down), all departing and ending in Britain and of 11-15 daysâ duration.