t STELL AR SPHERE Dan Crowson Spanning roughly 175 light-years in diameter, densely packed globular cluster M2 in Aquarius is one of the largest globulars known. Though located 55,000 l-y away, M2 is just visible to the unaided eye under extremely dark skies. DETAILS: Astro-Tech AT12RCT Ritchey-Chrétien telescope with SBIG STF-8300M CCD camera. Total exposure: 6 hours through LRGB color filters. q IN THE COMPANY OF POL ARIS Sérgio Conceição Stars of the northern sky appear to arc above the chapel of the medieval Castle of Noudar in Barrancos, Portugal. DETAILS: Canon EOS R Mirrorless camera with 14-mm lens at f/2. Total exposure: 25 minutes at ISO 2000. sk yandtele scope.com * D EC E M B E R 2 019 77http://www.skyandtelescope.com