[vsnet-chat 446] Re: SS Cyg: comparison between sequences

[bas@bom.gov.au (Bruce Sumner)]

Regarding Tycho magnitude errors

As there is no standard error for Johnson V in the Tycho Catalogue,
you would have to use the error quoted for VT (e_VTmag). Since
Johnson V is derived from VT and BT, the assumption that Johnson V
and VT share the same error would not be far from the truth. In
actual fact BT error should also be incorporated with VT error to
obtain a formal Johnson V error.

Bruce Sumner
Melbourne

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