Re: TASS CD 23 and loneos.phot

[jg <jg@jgws.freeisp.co.uk>]

Apologies

Most to possibly all of the VJ-Ic in the Brian Skiff photometry file I
used are calculated from BJ-VJ.

Unfortunately I had inadequate documentation in my possession and it
seems that not only was using an old copy but also one that had been
_modified_ from Brian's original.

The VJ magnitudes in his file are still measures.

Cheers

John G.

jg wrote:
> 
> Brian Skiff's loneos.phot file is a critical compendium of
> Johnson-Cousins BVRI photometry (quite a bit of which is sourced from
> Arne's data I think).  Though that doesn't make it a primary or
> secondary photometric standard, it is always something useful and to
> hand with which to make comparisons against other photometry sets,
> especially as it is nowadays quite large and covers a great deal of sky,
> allowing chance of matches.
> 
> There aren't enough matches from the TASS CD 23 and loneos.phot sets to
> warrant any graphing, so I'll just list up the 47 matches at a 2.5"
> radius cross-check.
> 
> Headings are more or less self explanatory (TASS ID is collected.big
> running number), the TASS CD 23 data and the loneos.phot data are
> separated midtable by columns of deltaVJ (TASS VJ - LONEOS VJ) and
> deltaVJ-Ic (TASS VJ-Ic - LONEOS VJ-Ic).  Note that I'm pretty sure Brian
> uses Ic, it being a Johnson-Cousins dataset, and does not use IJ, but I
> could have missed a point somewhere.