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Re: (IAAC) Thoughts on Data Sources (was: Basel 11B etc, etc.)



At 12:33 PM 3/13/98 -0500, you wrote:
>However, sometimes for more obscure objects the most up to date catalog is
NOT 
>the most common. Your suggestion to use Strasbourg-ESO is an example of
what I 
>mean: this catalog certainly seems to be the standard of reference, as 
>evidenced by Jeff B.'s use of it for 'dObjects'.
>
>However, 'dObjects' is also careful to provide a COMPLETE list of known 
>synonyms for objects. 
Taking nothing away from dObjects, I suspect that it does this specifically
because it uses the cross referencing information in Strasbourg-ESO. PN G
offers numerous ID's for each of its objects. It is not a 'new' catalog, in
that no-one did any new looking for PNe to make the catalog up; PN G is a
catalog of other catalogs and journal sources, combined into a
comprehensive (at the date of publication) and standardized format. As
such, it includes designators to all other catalogs that each planetary
appears in, as well as a citation to the original published source for the
PNe's discovery.
For example, for Sue's planetary in Hercules that she named, I used the PN
G to determine the other names of that object that I offered, that Sue had
not. There is no PK entry for that planetary, but PK planetaries are all
identified in the PN G, so if there was a PK designation, it could have
been included.
Similarly, I have run programs against the PN G to remove into separate
tables the PK, DDDM, and other PNe catalogs.
>This is for good reason: because the sources many 
>amateurs use to decide on new targets (or to find out more about old ones)
use 
>a variety of older catalogs to refer to them! E.g., various paper atlases
and 
>amateur catalogs still very frequently use Perek-Kohoutek (PK)
designations for 
>fainter planetaries. 
Unfortunately, if you want to include things like positions and magnitudes
in the netastrocatalog, you have to choose to get this data somewhere. PN G
positions are at least in a common epoch, and include the known corrections
that were available for the source catalogs and journal tables. This cannot
be said of the collection of smaller and less reliable PNe catalogs such as
the PK and its cousins, which are available to the amateur in many
versions, few of which have even the typographical corrections applied, and
some of which have pretty sloppy precessing to epoch 2000.
But the point is - if the netastrocatalog database is keyed to a PN G
number, and cross referenced to all other available designators, then you
have all of the hard work done for you already. The primary key has
enforced uniqueness, since PN G numbers are unique (there is no chance of
another kind of object, like an o/c, with the same number, I mean), and you
can still search on the other designations, since they are xref'ed. 
I am approaching this from the perspective of how I would set this up as a
database if it were my paying job; if it were done the way I describe, you
would insure back-compatibility to other amateur sources, while making the
job of controlling various designations much easier. When someone posts a
PK observation, it automagically gets stored under its PG N designation, as
well as its PK, DDDM, Sanduleak, IRAS, etc, etc, etc numbers.
If anyone wonders what the point of all this is, just wait till I post an
observation of M57 under its IRAS designator. A simple script would file
that under M57, its NGC number, PK number, KO number (if applicable) and so
on, making the observation much more useful to anyone who is looking for an
observation of anything. Lookup tables, while not terribly efficient, are
not going to be too expensive from a computing resource standpoint for this
purpose. OTOH, I am just running off at the mouth here, and my ideas may or
may not have any value, no matter what I would charge a paying client for
them.
--
Jeff Medkeff          | Acting Assistant Coordinator
Rockland Observatory  | Association of Lunar and Planetary
Sierra Vista, Arizona | Observers, Solar Section
On the web at http://shutter.vet.ohio-state.edu/

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