[Aavso-photometry] N CYG 05 (V2361 CYG) sequence measures

[Bjorn H. Granslo]

I refer to Richard Miles' informative report and will inform that I
independently have obtained the following magnitude results (for stars
that are apparently bluer than B-V = 0.7):

Star Name      Stack#1  Stack#2  Stack#3  Note
HD 191395       8.458*   8.451*   8.470*
HD 228002       -----    9.201*  ------
HD 228016       9.912*   9.888*   9.900*  AAVSO 99 = RJB 99
TYC 3154-3437  10.289   10.301   10.297   1'.6 N of HD 191529
HD 227928      ------   10.939   ------
TYC 3154-3339  11.304   ------   11.322   AAVSO 114 = RJB 112
TYC 3154-3577  11.562   11.560   11.547   AAVSO 115 = RJB 115
GSC 3154-3171  11.917   11.979   11.946   RJB 120
GSC 3154-3081  12.396   12.454   12.416   RJB 126
GSC 3154-3460  13.264   13.251   13.237   RJB 134

My results should be correct to within 0.03-0.05 mag. For Nova Cygni 2005
I have:

Star Name     Stack#1  Stack#2  Stack#3
V2361_Cygni    10.489   10.510   12.725

The measurements were made differentially by using HD 191395, HD 228002
and HD 228016 as calibration stars, with V-magnitudes for these stars
derived from Tycho-2 BT and VT photometry and by using the procedure
of Mike Bessell (2000, Publ. Ast. Soc. Pacific, 112, 961).

Stack#1 (18x10s) at 2005 Feb 15 01h38m UT, airmass X = 2.8. Image at
http://www.astro.uio.no/~bgranslo/images/ccd/V2361_Cyg_2005_Feb15.jpg

Stack#2 (18x10s) at 2005 Feb 15 01h44m UT, X = 2.8.

Stack#3 (60x10s) at 2005 Feb 20 01h12m UT  X = 2.9. Image at
http://www.astro.uio.no/~bgranslo/images/ccd/V2361_Cyg_2005_Feb20.jpg

Instrument: 20.3-cm SCT (working at f/3.3 w/focal reducer) + ST-7 CCD +
Schuler V-filter. The AIP4WIN programme was used for reductions
(stacking, dark frame and flat field corrections, and magnitude
measurements). No transformation corrections have been applied as my
setup appears to be close to the standard V-magnitude system. Despite
more simple equipment and procedure for reductions my measurements
agree well with those of Richard Miles.

I plan further observations of the nova and the reference stars.

Regards,
Bjorn H. Granslo (GRL)
Norwegian Astronomical Society
Variable Star Section