[Aavso-photometry] Nova Vul 2007: On the rise for sure

[Tim Crawford]

Richard,

Thank you for the update on the TYC 1628 0666 Stars V
= 9.802.

I have some 720 or so images from last night to reduce
at some point.

However, using your V value for the comp star I get
the following spread in my batches.

321.69576	8.368
321.71751	8.349
321.74450	8.361
321.77008	8.344 
Gap  - on another target
321.88532	8.223
321.90890	8.178
321.93109	8.143

Tim Crawford CTX
Arch Cape Observatory

--- RICHARD MILES <rmiles.btee at btinternet.com> wrote:

> Tim Crawford wrote:
> > Using two Tycho2 Stars, with "corrected" V I
> measured
> > the V mag at 8.403 at UT 2007/08/09/06/28/55.
> 
> > Comp Star:
> >
> > 19:54:40.66 +20:57:01.5 "corrected" Tycho2 V mag =
> > 9.861
> > (a bit red with a Bt-Vt of 1.286
> >
> 
> Tim - My preliminary measure on this comp star (TYC
> 1628 0666) gave V=9.802, 
> V-I=+1.18.  I have calibrated my frame zeropoints in
> V for the field 
> containing the nova against 6 Hipparcos stars to an
> absolute accuracy of 
> about 0.012 mag.  This suggests that your measure of
> the nova may actually 
> correspond to around V=8.34.
> 
> V photometry over a 45-minute period 23:19-00:04 UT
> under very good 
> conditions yielded the following trend, which
> corresponds to a rise rate of 
> 1.48 +/- 0.10 mag/day.  Block average data are as
> follows.  Each point is 
> the average of 100-180 sec of integration using a
> 6-cm refractor.
> 
> 321.4722 8.930
> 321.4746 8.931
> 321.4781 8.920
> 321.4804 8.915
> 321.4832 8.911
> 321.4856 8.907
> 321.4914 8.897
> 321.4937 8.897
> 321.4960 8.905
> 321.4982 8.895
> 321.5005 8.884
> 321.5028 8.882
> 
> Looks to be on a strong rise at present.  According
> to my calculations, your 
> measure might indicate a slightly accelerating
> brightening!
> 
> Richard Miles
> 
> 
>