[Kstars-devel] More star catalog issues

[Jason Harris]

Hi Andrew,

Great, thanks for taking a look at this.  It looks promising, at least
for adding missing magnitude data, and possibly improving the
coordinates for some objects.

Before you go further, I should have asked you: have you used the
Download New Data tool to get the improved Steinicke NGC/IC catalog?
That catalog's data has much more complete information...the problem
with it is that it's only available for non-commercial use (which is
why we don't ship it directly with KStars as the default catalog).

So, for the purposes of improving our default catalog, please make
sure you are *not* working from the Steinicke catalog.

On Tue, May 27, 2008 at 9:58 AM, Andrew Buck <andrew.buck at ndsu.edu> wrote:
> Visual inspection of the first half dozen or so shows the magnitudes to
> be different but close so automatic combining/checking might be
> difficult.  This may be because the KStars database shows B Magnitude, I
> think, whereas Wikipedia lists visual magnitudes.  I have recently begun
> learning IRAF which is a very powerful astronomy package and it seems to
> have some tools for doing exactly this but I have yet to learn to use
> them.  You seem to be able to do a "diff" of two files but not just
> return lines that differ by character but actually read in values and
> check to see if they differ by more than a certain value.
>
I use IRAF all the time in my everyday work...I don't think it will be
of too much help here.
I was thinking you or I could write a (python|perl|ruby) script that
goes line-by-line through our NGC catalog, and figures out if your
parsed wikipedia data provides an improvement in either position or
magnitude.  If so, the relevant field will be replaced.

It would be really great if we could get our hands on angular size and
position angle data as well...ooh, it looks like simbad reports
major/minor axis length and position angle.  For example, here is the
simbad result for M 31:
http://simbad.u-strasbg.fr/simbad/sim-id?Ident=m+31&NbIdent=1&Radius=2&Radius.unit=arcmin&submit=submit+id

the line labeled "Angular size (arcmin)" has three values, these are
the major and minor axis length in arcmin, and the position angle in
degrees.  We can send batch queries to simbad to retrieve the data for
a large number of objects, but maybe that's a TODO item...let's see
what wikipedia can do for us.

> If this data is useful to anyone I would be happy to do the remaining
> NGC objects and possibly the IC objects if the page is formatted
> similarly but I don't want to go to the trouble if the data cannot be
> used anyway.  Also reordering the fields, etc, should be fairly
> starightforward so let me know if that would help.  I will look into the
> IRAF thing if I can but that could be some time, and/or I might never
> figure it out.
>
Yes, please do the rest of them if it's not too much trouble!  Or, we
could try a quick match for these first 1000 objects to make sure it's
worth doing first.

regards,
Jason


> -Buck
>
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