slothman

Celestial Object: Much too general

2008-01-14T19:06:06.0007Z

My understanding of this type is that classes of objects should not be co-typed as "celestial object". If you see any, feel free to de-type them. As far as its being a very general type, that's by design -- it holds a number of properties that are common to all or most kinds of celestial object, which both saves us from having to include the same properties on a large number of types, and also makes writing queries much easier. (I.e., if you want to know all objects with an absolute magnitude of > 4 or whatever, you only need to query against one type, rather than create separate queries for every type.)

Freebase has a non-hierarchical structure, so "celestial object" is an included type of comet, planet, etc. If you look at the topic for Comet Hale-Bopp, you can see that it has both the comet and celestial object types, which gives it the full range of properties of both types.

Celestial Object: Much too general

2008-01-13T11:58:20.0005Z

This is much too general of a type. Just purusing the list of what is in here already, I see comets, planets, stars, supernova remnants, etc. I also see individual objects (eg, individual comets) as well as classes or types of objects (eg HII regions). You might consider structuring the schema like this:

Celestial Object -> Object Type -> individual Object

Celestial Object -> Comet -> Hale-Bopp

Celestial Object -> Supernova Remant -> Crab Nebula

You will still likely run into issues, but at least things will be classified in a more meaningful way.

(Just an aside, "Nebula" is also a generic (and antiquated) term which can describe vastly different types of objects - Crab Nebula => supernova remnant, Orion Nebula => star forming region, Andromeda Nebula => galaxy).

Celestial Object: Spelling nitpick

2007-07-25T20:14:34.0011Z

The term is "Right Ascension". http://en.wikipedia.org/wiki/Right_Ascension It's not really appropriate for anything closer than a star unless you want to make properties that are calculated from an algorithm rather than being a static floating point number.

Celestial Object: Distance (parsecs) - from where?

2007-07-14T12:39:57.0004Z

from earth? solar system? sun? center of containing galaxy? and since it is moving, i guess it should be either time related (when it was calculated) or average.