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.
Northern Lights: best time - Norway Forum. Northern Lights: best time. Leeds, United... I'm looking to book a 5/6 day 'cruise' with Hurtigruten from Bergen to Tromso to see the Northern Lights but am unsure as to the best time. January offers 24 hours of night sky but, presumably, little light with which to view the Norwegian coast.