UPDATED! We have switched to the Bohlin 2006 version of 
Vega, based on alpha_lyr_stis_003.fits downloaded from
ftp://ftp.stsci.edu/cdbs/cdbs2/current_calspec
This is the new default "VEGA".

We've also updated the default Vega magnitudes to be
V = 0.023 (+/- 0.008) based on the most recent Bohlin
results. (Bohlin 2006, astro-ph/0608715)

-sj 2006-Oct-12

---
Probably the best Vega, based on my subjective look, is the one 
from STSDAS(v3.3)/synphot. It is called synphot_vega.dat; 
I got it from /iraf/extern/stsdas/lib/vega.dat
and added a little header describing it from the stsdas 
documentation.  

I'm linking it to the file VEGA; it will be our default.
The routines will be written so you could use one of the
others by specifying it manually.

-sj 2005-Oct-29
---

Adam says:

> One thing to mention.  For HST Vegamag zeropoints, the zeropoints
> are defined by dividing the Bohlin/Gilliland spectrum of Vega by
> the synthetic, so that by definition, an HST vegamag would give
> mag=0.0 for Vega itself if it could be observed by HST.  Since
> Vega actually has a mag ~0.025-0.03 if observed by Landolt, then
> I believe we need to adjust all the HST mags by the Landolt
> magnitude of Vega.  Do you agree?

So that means the zeropoints of HST filters using (using vegamag
magnitudes) should give our Vega spectrum zero magnitude in all
filters. So I've created a "HSTvegamag" set of magnitudes for Vega
(all 0.0). This should be used for all HST filters.

-sj 2005-Dec-12


