It looks like Casey is +11 in southern summer and +8 in southern winter - apparently they're supplied out of Tasmania, so they match Tasmanian time in the summe

It looks like Casey is +11 in southern summer and +8 in southern winter - apparently they're supplied out of Tasmania, so they match Tasmanian time in the summer, but match the time of their longitude during the winter. Something similar happens at the Norwegian base Troll, which is +0 in southern summer (in accordance with its location) and +2 in southern winter (which is northern summer, so they match the time in Norway).