RT @ProfAbelMendez: Available from the Naval Observatory: “Astronomical Phenomena for the Year 2017” [2016 version is free as a PDF] buff.ly/1J3l2Wh
RT @ProfAbelMendez: Available from the Naval Observatory: “Astronomical Phenomena for the Year 2017” [2016 version is free as a PDF] buff.ly/1J3l2Wh