[vsnet-chat 4312] Re: Re Confirmation and Reporting Observations

[Taichi Kato <tkato>]

Re: [vsnet-chat 4311] Re: Re Confirmation and Reporting Observations

> The AAVSO data has an
> advantage in that the comparison stars used are standardized for
> each star, so there is no uncertainty there; zero-point errors
> are therefore minimized.

   The situation is much more favorable than in the past.  Nowadays most
variable star organizations (including VSNET) use the international
standard V system as comparison star sequences.  I believe newly created
variable star charts (disregarding some preliminary ones for early
observations of novae etc.) will be eventually in common magnitude scale
regardless of the chart source.  VSNET is one of such organizations which
took the initiative to standardize variable star charts using Hipprcos/Tycho
magnitudes and CCD V measurements.

>    I don't know if AAVSO keeps track of the average zero-point error
> for individual observers and then applies that to the raw
> observations before making them available to researchers.

   No zero-point adjustments have been applied, as I have heard from
Dr. Mattei.  Serious problems exist in observations on old sequences,
but I have heard that the AAVSO staffs don't have time to convert them to
the modern scale (they have more urgent things to do).

Regards,
Taichi Kato

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