[vsnet-obs 10273] NAS.VSS report no. 1 on SN 1998S (1998 Mar. 11)

["Bjorn H. Granslo" <b.h.granslo@astro.uio.no>]

Norwegian Astronomical Society - Variable Star Section

  OBSERVATIONS OF SUPERNOVA 1998S IN NGC 3877 - NAS.VSS REPORT NO. 1
  ==================================================================

Supernova 1998S: R.A. = 11h 46m 06s.0, Decl. = +47o 28' 55"  (J2000.0)
 [Type IIn]       (Offset from nucleus of parent galaxy: 14" W, 46" S)

-----------------------------------------------------------------------
YYYY MM DD.DDD  OBSERVATIONS   MAG  CL NOTES INSTRUM.   OBSERVER
-----------------------------------------------------------------------
1998 03 10.017    x+2;y+5     12.2  2    M   C203;200x  Granslo, B. H.
1998 03 10.098  x+2;y+3;A+3   12.3  2    M   C203;200x  Granslo, B. H.
1998 03 11.044  6-3;x+3;A+3   12.2  2    M   C203;287x  Granslo, B. H.
-----------------------------------------------------------------------

Time system is year, number of month and date with decimals in U.T.
Observations are Pogson step estimates. Magnitudes are derived from
these estimates by using the sequence below. The deduced magnitudes are
subject for revision when more precise magnitudes of the comparison
stars become available. CL = class: estimated accuracy of observation;
1 = good (+/- 0.1 mag.), 2 = fair (+/- 0.2 mag.), 3 = poor (+/- 0.3
mag. or more). NT = notes: M = Moon. Instrument (type, aperture in mm
and magnification): C = catadioptric telescope (SCT).

Observers: Bjorn H. Granslo (Fjellhamar, Norway).

List of comparison stars:
-----------------------------------------------------------------------
Ident   Star Name     R.A. (2000.0) Decl.  V-mag.  B-V  Ref. Notes
-----------------------------------------------------------------------
                      h  m   s    o  '  "
  1     HIP 57399    11 46 03.0 +47 46 46   3.69  +1.18  H   Sp. K0III
  2     HIP 57349    11 45 31.0 +47 40 03   8.06  +0.62  H   Sp. G2V
  3     HIP 57385    11 45 55.5 +47 32 51  10.00  +0.78  H   Sp. K0
  4   TYC 3452-1157  11 47 12.9 +47 47 15  10.42  +0.55  T
  5   TIC 3452-1079  11 47 39.9 +47 32 41  11.20:  ....  TI  (b-r)=+0.5
  6   TIC 3452-1149  11 45 44.9 +47 47 42  11.8    ....  TI
  7   GSC 3452-0905  11 47 09.0 +47 23 34  11.9 :  ....  G1
  8   GSC 3452-1238  11 45 26.8 +47 48 32  12.2 :  ....  G2  (b-r)=+0.7
  x   GSC 3452-1101  11 45 35.6 +47 33 12  12.5 :  ....  G2  (b-r)=+1.1
  y   GSC 3452-1061  11 46 29.2 +47 31 09  12.6 :  ....  G2  (b-r)=+0.2
  A   GSC 3452-1170  11 46 20.1 +47 35 32  12.6 :  ....  G2  (b-r)=-0.3
  B   GSC 3452-1091  11 45 41.5 +47 32 47  13.2 :  ....  G2  (b-r)=+0.6
  C   GSC 3452-0978  11 45 30.1 +47 26 41  13.8 :  ....  G2  (b-r)=+1.1
  D   GSC 3452-0997  11 46 38.0 +47 27 36  14.5 :  ....  G1
  E   GSC 3452-0977  11 45 34.8 +47 26 49  15.0 :  ....  G1  (b-r)=+1.6
-----------------------------------------------------------------------

This list contains field and sequence stars within ~20' from the
supernova. Identifications are from TA E-Circular 1278 (capital
letters) and NAS.VSS (others). Star 1 is Chi UMa. Positions are given
to a precission of 0.1s in R.A. and 1" in Decl. V-magnitudes followed
by a colon (:) are uncertain. References to positions and magnitudes
are H = Hipparcos Catalogue, T = Tycho Catalogue, TI = Tycho Input
Catalogue, G1 = Guide Star Catalogue, Ver. 1.1 [GSC] (single entry),
G2 = GSC (mean of two entries). The colour indices (b-r) are based
on the PPM USNO-A1.0 catalogue.                   (BHG/1998/03/11)

VSNET Home Page

Return to Daisaku Nogami

---

vsnet-adm@kusastro.kyoto-u.ac.jp