MBCAA Observatory

ASAS1749-13 = NSer2005 = V378 Ser

Observations: 5 Apr 2005

Michel Bonnardeau
6 Apr 2005
Updated: 7 Apr 2005, 13 Apr 2005

Abstract

V and B photometry measurements are reported for this nova.

Introduction

This object was discovered by G. Pojmanski with the ASAS (CVNET-discussion 3 Apr 2005) on 18 Mar 2005 and first reported as a dwarf nova. Further observations reported on CVNET-discussion give variations of amplitude < 0.1mag and B-V=0.7. It is a nova (NSer2005 = V378 Ser).

Observations

The observations were carried out with a 203mm SC telescope, Johnson B and V filters used alternatively and a SBIG ST7E camera (KAF401E CCD). Each exposure is 1 minute long. 36 images were obtained with the V filter and 32 with the B filter. A sample image is here.

The comparison star is Tycho 2 5669-00822 with Johnson magnitudes (computed from the Tycho magnitudes) B=11.191 V=9.731. There are 2 check stars K and K1:

  • K star is Tycho 2 5669-00675 with Johnson magnitudes B=12.443 V=11.257. It is observed with b=12.600 (standard deviation 0.056) v=11.534 (0.023);
  • K1 star is Tycho 2 5669-00677 with Johnson magnitudes B=11.952 V=10.972. It is observed with b=12.166 (0.030) and v=10.927 (0.010).

    • The discrepancies in the check stars between Tycho magnitudes and my measurements may come from:

  • the guiding is not very good and I did not use the photometry apertures that large because the field is crowded;
  • the sky was hazy;
  • I was not able to make flats so I use old twilight flats;
  • the photometry was not transformed.

    • The light curves:

    Blue: the B magnitudes, Green: the V magnitudes. The error bars are +/- the 1-sigma statistical uncertainties. They are large at the end of the session because of the twilight.





    Astrometry

    From UCAC2, the 2000.0 coordinates are:
    RA=17h49mn24.51s
    DEC=-12°59'59.2"
    with an uncertainty of +/-0.5".

    I searched for a counterpart in the USNO-B1.0 catalog, taking into account the proper motions. I found none. Either the precursor was too faint for USNO-B1.0 or the proper motion is not known.

    Technical notes

    Telescope and camera configuration.

    Computer and software configuration.
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