[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]
[vsnet-campaign-nova 24] V382 Vel recent data
Hi Mati and all,
After reading Dr Retter's comments regarding oscillations in V382 Vel I was tempted to reply similarly. Oscillations of exactly 24 h are possible but unlikely. There must be a difference in the sequence used.
I'll make an effort to look at my comparison stars and will forward them here.
From memory I know I use a mixture of AAVSO and Tycho values It's not a good approach, I know, but certain 'published' mags look wrong or belong to stars far too red to be suitable.
Regards,
Berto
>>> "Mati Morel" <morel@ozemail.com.au> 07/04/00 08:38AM >>>
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
vsnet-adm@kusastro.kyoto-u.ac.jp
Return to Daisaku Nogami
vsnet-adm@kusastro.kyoto-u.ac.jp
VSNET Home Page