[Aavso-photometry] RE: [AAVSO-DIS] RE: AAVSO special notice 5object

Mon Feb 13 10:25:30 EST 2006

Hi Arne

If you don't have other (low accuracy) catalog mags, what about:
    Using the average galactic color indices and applying them to
    the know V mag value to get preliminary mags in the other
    bands ?

This would seperate the lightcureve in the different bands and "on
average" should not place them too far off for a later correction.

The question would be what color indices to use for this
procedure.

Clear skies
  Wolfgang

-- 
Wolfgang Renz, Karlsruhe, Germany
Rz.BAV = WRe.vsnet = RWG.AAVSO

----- Original Message ----- 
From: "arne" <arne at aavso.org>
To: <aavso-photometry at mira.aavso.org>
Sent: Monday, February 13, 2006 3:57 PM
Subject: Re: [Aavso-photometry] RE: [AAVSO-DIS] RE: AAVSO special notice 5object

> The submission method as described by Aaron is fine for now.  Note that
> this is a way in which you can submit *any* differential photometry, by
> either using a reasonable guess for the comp star magnitude, or else
> just setting it equal to zero and submitting the raw differential data.
> I don't recommend the latter since our staff looks at the data and having
> differential data (say, +/- 1 mag) show up on the same screen as the
> regular magnitudes (say 12-14mag) throws off the display scaling.
> 
> If you don't know the magnitude of the comp star from some true calibration,
> use USNO-A/B/Tycho/etc.  Be *sure* to report the magnitude used for the
> comp star along with its identification.  Do *not* do ensemble photometry
> under these circumstances, as there is no way we can subsequently correct
> the data.  If you need to do ensemble photometry, then make a request to
> the AAVSO for the magnitudes of your comp stars, and wait to submit until
> we can get accurate magnitudes for you (may be days to months).
> Arne
> 
> Aaron Price wrote:
> > (Note I've removed aavso-discussion from the CC: list since this involves 
> > photometry.)
> > 
> >  This is a good question about a grey area.  Current AAVSO policy is to
> > submit absolute magnitudes, not differential. If you don't have a
> > magnitude of the comp star in the same filter as your observations then
> > what you basically have is a differential estimate with an offset. So we
> > recommend that you not submit that data until you can find an appropriate
> > comparison star value.  When possible, we find the photometry and will
> > post it and/or update the chart. But that is sometimes not possible,
> > especially for faint stars in the southern hemisphere. That is something
> > for which I don't have an answer for. Perhaps Arne does. I do know it is
> > something we plan to address with our upgrade of WebObs and the
> > observation pipeline in the next year.
> > 
> >  Note on your other comment, put the magnitude in the "comp star" field
> > and then the GSC ID# in the Comments Explained field. And then use Comment 
> > Code "G" (for Guide Star magnitudes).
> > 
> > Aaron
> > 
> > 
> > 
> >>The next question is what to do with my B, R, and I data.  If I use the same GSC
> >>as a reference star and use its nominal GSC magnitude, that is patently wrong
> >>and likely going to confuse users of the data if I can't also report the
> >>magnitude I assumed for the reference star.  These questions have been raised
> >>before of course.  Any updates on the progress of resolving the issue?
> >>
> >>Thanks!
> >>Walt
> >>
> >>
> >>
> >>
> >>
> >>-----Original Message-----
> >>From: aavso-discussion-bounces at mira.aavso.org
> >>[mailto:aavso-discussion-bounces at mira.aavso.org]On Behalf Of
> >>arne at aavso.org
> >>Sent: Sunday, February 12, 2006 12:05 PM
> >>To: Tom Krajci
> >>Cc: aavso-photometry at mira.aavso.org; aavso-discussion at mira.aavso.org
> >>Subject: Re: [AAVSO-DIS] RE: AAVSO special notice 5 object
> >>
> >>
> >>Hi Tom!  Seiichiro Kiyota indicates that this object
> >>is very red (B-V = 1.49), so that is why your unfiltered
> >>differential photometry will have a large offset from Walter's.
> >>For most novae, it is better to use a standard filter.
> >>At 11th magnitude, you shouldn't have any problem using
> >>a V filter for example.  Classification waits on a
> >>decent spectra.  It is in a tough spot for a single site
> >>to follow, so observations from everyone at all of our
> >>longitudes will be essential to follow its light curve.
> >>Arne
> >>
> >>On Sun, Feb 12, 2006 at 10:12:53AM -0700, Tom Krajci wrote:
> >>
> >>>>From: "Walt Cooney" <waltc at cox.net>
> >>>
> >>>>I imaged the area of the ASAS object reported in AAVSO Special Notice 5
> >>>
> >>>this
> >>>
> >>>>morning and can confirm the new object.   It is approximately 0.8
> >>>
> >>>magnitudes
> >>>
> >>>>brighter in V than the nearby star GSC 6826:280.  I am taking a time series
> >>>
> >>>in V
> >>>
> >>>>now.
> >>>
> >>>I have submitted about 90 minutes of time series data from this morning via
> >>>WebObs...call it up in Quick Look by the designation 1727-24.  My unfiltered
> >>>data shows it to be about 0.4 mag brighter than GSC 6826-0280.  No signs of
> >>>modulation/humping.
> >>>
> >>>Tom Krajci
> >>>Cloudcroft, New Mexico
> >>>http://overton2.tamu.edu/aset/krajci/
> >>>
> >>>
> >>>
> >>>--
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> > 
> 
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