It’s 3:13 a.m. and the phones in my suite on board Hurtigruten ’s MS Trollfjord are abuzz. Elation and middle of the night calls don’t usually go hand-in hand, but when you’re searching for the northern lights , these pings can only mean good news. The aurora borealis is the entire reason for this journey up Norway’s coast and our first major sighting has felt like a long time coming. My husband and I are 7 days into the 15-day sailing and cloudy skies have stolen our chances. (We did get a brief glimpse of the Aurora Oval —a stable ring of auroral light above the Earth’s geomagnetic North Pole—as we sailed under it on day four.) We are 2 of the 25 people who’ve signed up to be part of the inaugural Astronomy Voyage group on a premium, all-inclusive Signature cruise led by Hurtigruten’s Chief Aurora Chaser , Tom Kerss.…