<br><br>Hi Eric,<br><br>when doing fringe fitting, we can choose to solve "phase","delay",and "rate",<br><br>but i am confused about the "phase" noted above. <br><br>The error of the interferometer phase can be expressed as:<br><br><img src="data:image/png;base64,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!
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!
DgiBit1uZ2o4UyiRzAlqpq03Y6zoc2EVMhhCVvajxMAD2LB2LoHK82kEiup8aRuGJrR1Vj
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!
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!
EwSiGBDSuw7N5JCoY1SOieeknHF5Xob2KYYFzolr8Bzxhz/jOhc9dkZYNOlY09HHzjn4Mk
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!
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!
YAnUiYI6pTnStbEPAEKiEgDmmSrBZJkPAEKgTAXNMdaJrZRsChkAlBMwxVYLNMhkChkCdC
JhjqhNdK9sQMAQqIWCOqRJslskQMATqRMAcU53oWtmGgCFQCQFzTJVgs0yGgCFQJwLmmOpE18o2BAyBSgiYY6oEm2UyBAyBOhEwx1Qnula2IWAIVELAHFMl2CyTIWAI1ImAOaY60bWyDQFDoBIC/wKD2SrmpKz74wAAAABJRU5ErkJggg==" alt="" height="72" width="294"><br>so the "phase" solved by aips task "fring" means the <img src="data:image/png;base64,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!
b+5XEkYSprfiAAAAAElFTkSuQmCC" alt=""> in the above fomula, or something else?<br><br>thanks for the helps,<br><br>hongmin<br><br><br><span></span><br><br><br>