This story has been made freely available as a public service to our readers. Please consider supporting SCMP’s journalism by subscribing.Hong Kong is set to witness a rare total lunar eclipse on Tuesday night, but the weather forecaster warns that thick clouds and possible rain may block the view.The Hong Kong Observatory also said temperatures were expected to drop gradually from 20 degrees Celsius (68 Fahrenheit) at noon on Tuesday to around 16 degrees in the evening.The astronomical event...