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[vsnet-campaign-nova 23] Re: V382 Vel recent data
The recent observations on V382 Vel (below) suggests that different
comparison stars are almost certainly in use, and while they may be the best
available (Tycho), the discrepancy may cause variations which are not
intrinsic to the nova.
The two Australian observers from the VSS, RASNZ (Andrew Pearce and Peter
Williams) are presumably using comparison stars GSC 8210.01423 (9.94V, 0.51
B-V) and GSC 8210.00801 (10.43, +1.27) as shown on my chart VSM84 of 2000
March 2000. These two observers have consistently reported the nova at 10.3
or 10.4. However, the other observers, especially Berto Monard (South
Africa) and S. Opero (South America) have consistently reported the nova at
10.8. This suggests to me that they are using GSC 8210.01225 (10.77V) and/or
GSC 8210.00897 (10.77V) as comparisons. Would this be so, Berto? Being well
aware of the vagaries of Tycho mags at this level, errors of a couple of
tenths in the Tycho mags
can exaggerate the normal observational errors and produce fictitious
fluctuations. I am unable to say which of the Tycho mags are the culprit.
If one is looking for periodic modulations one should ensure the dataset is
produced by observers working to the same set of consistent, reproducible
condtions. The choice of comparison stars can be critical. I doubt that
these conditions are currently being met.
Cheers,
Mati
Morel Astrographics
c/o M. Morel, 6 Blakewell Rd, Thornton NSW 2322 AUSTRALIA
*Specialized Charts** Variable Star Studies** Stellar Data**
151o38'33" E, 32o46'47"S. morel@ozemail.com.au
----- Original Message -----
From: Alon Retter <ar@astro.keele.ac.uk>
To: Taichi Kato <tkato@kusastro.kyoto-u.ac.jp>
Cc: <vsnet-campaign-nova@kusastro.kyoto-u.ac.jp>
Sent: Tuesday, July 04, 2000 1:51 AM
Subject: [vsnet-campaign-nova 21] Re: V382 Vel recent data
> > This object will be a good target in the coming season, in order to
> > search for periodic modulations.
>
> I agree. The recent estimates might suggest a possible variability.
>
> Regards,
> Alon
> -------------------------------------------------------------------------
> Dr. Alon Retter Tl. (work) +44-(0)1782-58-3493
> Physics Dept. Fax (work) +44-(0)1782-711093
> Keele University -----------------------------------
> Staffordshire 'As a scientist I don't believe myself, so
> ST5 5BG, U.K. why should I believe you?' (A.R. 1965-2085)
> -------------------------------------------------------------------------
> On Wed, 28 Jun 2000, Taichi Kato wrote:
>
> > V382 Vel recent data
> >
> > This object will be a good target in the coming season, in order to
search
> > for periodic modulations.
> >
> > YYYYMMDD(UT) mag observer
> > 20000517.550 103 (A. Pearce)
> > 20000518.484 104 (A. Pearce)
> > 20000518.522 104 (A. Pearce)
> > 20000519.540 104 (A. Pearce)
> > 20000521.493 103 (A. Pearce)
> > 20000521.712 108 (B. Monard)
> > 20000522.474 103 (A. Pearce)
> > 20000522.516 103 (A. Pearce)
> > 20000523.453 103 (A. Pearce)
> > 20000524.432 103 (P. Williams)
> > 20000524.541 103 (A. Pearce)
> > 20000525.485 103 (A. Pearce)
> > 20000526.456 103 (A. Pearce)
> > 20000527.033 106 (E. van Ballegoij)
> > 20000601.479 104 (A. Pearce)
> > 20000602.465 102 (P. Williams)
> > 20000603.730 108 (B. Monard)
> > 20000604.040 109 (S. Otero)
> > 20000605.456 104 (A. Pearce)
> > 20000606.428 102 (P. Williams)
> > 20000608.508 103 (A. Pearce)
> > 20000611.496 103 (A. Pearce)
> > 20000617.459 103 (A. Pearce)
> > 20000622.690 108 (B. Monard)
> > 20000626.685 108 (B. Monard)
> > 20000627.519 104 (A. Pearce)
> >
> >
>
>
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