A mat­ter of time

Archie Howitt, Ed­in­burgh

Sky at Night Magazine - - INTERACTIV­E -

Please con­vey my thanks to Bev (In­ter­ac­tive, Oc­to­ber 2018) for his diplo­matic way of cor­rect­ing my er­ror. I have fixed my True North So­lar Com­pass and used it to align my tele­scope and mount. Us­ing the sun­dial time cor­rec­tion form at www.ppow­ers.com/ EoT.htm and the time cor­rec­tion at my lo­cal merid­ian, I noted that the Equa­tion of Time (EoT) on 16 July – when I wrote my first let­ter (In­ter­ac­tive, Septem­ber 2018) – was –6m 5s, and with­out cor­rect­ing for this and my lo­cal merid­ian my align­ment was out by 4.5°. How could I have not ac­counted for my lo­cal merid­ian? I set this ev­ery time I power up my mount. I’ve also read about the EoT but stored the in­for­ma­tion in some deep in­ac­ces­si­ble re­cess of my mind. My only ex­cuse is never trust a me­te­o­rol­o­gist – they can never get the weather right ei­ther!

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