Star names containing the Greek letters µ and ν, and the case of “u” versus “U”

When searching for a star in the International Variable Star Index (VSX) or reporting observations to the AAVSO International Database via WebObs, it is not possible to enter a Greek letter if the star has a Greek letter as part of its name – one cannot search for “µ Cep” or “ν Pav”. There has been ongoing confusion about how to spell out some of the Greek letters used in star names, and in particular about how to spell out µ and ν.

Why does it matter how they are spelled? There are stars whose Argelander names look the same as those with Greek names, especially to case-independent software. Thus, to VSX or WebObs “mu Cep” (µ Cep) looks the same as “MU Cep” (M-U Cep), and “nu Pav” (ν Pav) looks the same as “NU Pav” (N-U Pav).

A few years ago the AAVSO asked observers to use the Russian three-letter spellings, so µ became “miu” and ν became “niu”. An article was written for the AAVSO Newsletter and the AAVSO website ( specifying how Greek letters were to be written when submitting data.

This policy was not adopted when VSX was created, and those stars were searched for in VSX as, for example, “mu Cep” and “nu Pav”. However, the desired star was not always found because the software could not make a distinction.

VSX HAS CHANGED: For the primary name in VSX, the spelling of µ and ν have been changed from “miu” and “niu” to “mu.” and “nu.”, respectively. These modified spellings conform to the current GCVS usage. For example, to search for “µ Cep” in VSX, enter “mu. Cep”.

NO CHANGE: When submitting observations to the AAVSO International Database, please continue to use “miu” and “niu” for Greek letters and "MU" and "NU" for Argelander names.

HELP US: Also, if you find instances in the database where data are mixed (e.g. data for miu Cep and MU Cep are together) please notify headquarters, or use the Zapper utility ( to flag them for us so we may sort them into their correct identities.

ALSO: On a parallel issue, there has been the ongoing problem of “u Her” versus “U Her”, with the data often appearing mixed. HERE IS THE CHANGE TO VSX: For “u Her”, please search for  it as “u. Her”.  WHEN SUBMITTING DATA: report “u Her” as “u. Her” or “68 Her”.

Good observing, searching, and reporting!