Re: color terms

[Robert Creager <Robert_Creager@LogicalChaos.org>]

On Sat, 23 Feb 2002 11:38:14 -0500
Stupendous Man <richmond@a188-l009.rit.edu> said something like:

>                                                         2
>                            [  V - (v + a + b*(v - i )) ]
>              2                          j      j   j
>           chi   =   sum  --------------------------------
>                                 2         2          2
>                           sig(V)  + sig(v)   + sig(i)  
>    
> 

Just looking at re-doing my color/zero point calculations to speed them up
(currently iterative).

My question is, what would someone who knows what their doing, do with the sig
(uncertainty) terms when they don't know what they are?  I have sig(v) and
sig(i) (from DAOPHOT), but haven't a clue what to use for sig(V)/sig(I), as they
are calculated from Tycho2's BT and VT via Arne's terms.

Ignoring them doesn't seem right.  Can sig(V)/(I) somehow be calculated from the
original e_BT and e_VT terms in Tycho2?

Thanks,
Rob

-- 
 22:17:22 up 16 days, 15:00,  4 users,  load average: 2.15, 2.63, 2.90

PGP signature