[Aavso-photometry] Nova Vul 2007: On the rise still?

[RICHARD MILES]

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