[vsnet-chat 962] Re: vsnet chart files

[Taichi Kato <tkato>]

McAdam wrote:

> After a query from Gary Poyner, I note the x/y numerical values in the chart
> files have been extended so that they now create an error in my Basic plot
> programme placed some weeks ago on the BAAVSS home pages.
> <http://vsnet.telf-ast.demon.co.uk>

   Thank you very much for providing a useful tool to the variable star
community.  If you have a fixed URL for the program, I will be able to add
a reference to your program in every chart posting.

> The program needs to be re-written to deal with the above problem but I am
> puzzled that the new SCALE heading is not included in every file.

    Sorry, I often forget writing the scales (repost ones are necesarily
devide of them); in case SCALE keyword is missing, please assume 0.02 for
the default value.

> Negative x/y values are not always used, either.

    Ouda CCD-based charts have no negative coordinates, but others (GSC
and USNO) may contain such stars having negative coordinates.  The origin,
the center of the chart is fixed (9600, 14400).  The scale and coverage
of the sky may vary.

> Is there a description or FAQ of the chart files anywhere on VSNet?

    I think there has been such a documentation.  I hope I will be able
to dig it out from the pile of previous e-mail diskettes.

Regards,
Taichi Kato

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