December’s full Moon arrives this week with extra oomph and an appropriately frosty name — the Cold Supermoon — to match the season. Why it matters: For skywatchers, photographers and people who love the night sky, Moon watching is one of the easiest celestial events to catch — no telescope or expertise required. The big picture: This week’s supermoon will sit about 221,965 miles from Earth when it hits peak illumination on Thursday. At perigee,…