Distance

This can be catalogued as parallax (in arcsec etc), distance modulus (DM) (derived from flux density/magnitude and/or other assumptions e.g. nature of object, redenning) or plain distance (in parsec etc.). (For other objects spectral information - Galactic HI absorption, extragalactic redshift etc. might be relevant). In most cases the uncertainties are large and the values are model-dependent; AstroGrid should use sensible defaults but allow the user to over-ride if wanted.

-- AnitaRichards - 23 Apr 2003