COMMISSION 27 OF THE I. A. U.
       INFORMATION BULLETIN ON VARIABLE STARS
                   Number 1610

                                Konkoly Observatory
                                Budapest
                                1979 May 18




PHOTOELECTRIC OBSERVATIONS OF THE 1946 OUTBURST OF THE
      RECURRENT NOVA T CORONAE BOREALIS



    The outburst of T CrB on 9 February 1946 occurred
just as a study of the characteristics of photomultipliers,
wide-band filters, amplifiers, and recording devices was
getting under way at the Lick Observatory. Now, these
many years later, with the benefit of experience and photometric 
catalogs, it is possible to reduce some photoelectric
observations made at that time to the UBV system.
    The observations consist of tracings of the brightness
of T CrB and comparison stars on an Esterline-Angus recorder 
made with the Lick 12-inch (30cm) refractor. Magnitude
differences between T CrB and Delta CrB were measured through
no filter at all or a neutral glass filter to equalize the
size of the deflections. Colors were measured through two
Corning filters: 5mm BPu for the blue and 2.01mm Noviol A
for the yellow. Three multipliers were used: RCA 931A on
10 February, 1P21b on 12, 13, and 14 February, and 1P21a on
the rest of the nights. The effective wavelength of the 
unfiltered observations is about 4300 A; hence, in Table I the
brightness of T CrB is expressed as B. It is based on the
difference in magnitude, corrected for the difference in
color between the two stars, and V = +4.64m and B-V = +0.80m
for Delta CrB.

                            TABLE I

           Observations of the 1946 Outburst of T CrB

                 JD (Hel)        average            average   no. of
Date (UT)        2430000+      B deviation    B-V   deviation obser.

10 Feb.         1861.961       3.68m+-0.10m                     4
                1862.021       3.66+-0.05                      11
                    .063                     +0.1m              1

12 Feb.         1863.925                     +0.27              1
                    .951       4.85+-0.01                       4
                    .984       4.87                             3

13 Feb.         1864.942       5.29                             3
                    .985                     +0.07+-0.01        5
                1865.003       5.35                             3

14 Feb.         1865.949       5.71                             3
                    .979                     +0.13+-0.05        5
                1866.013       5.70                             3

23 Feb.         1874.964       9.11                             3
                    .965                     +0.4               2

24 Feb.         1875.907       9.44                             2
                    .909                     +0.52              2

26 Feb.         1877.906       9.35                             3
                    .909                     +0.50              2

1 Mar.          1880.904                     +0.50              2
                    .905       9.66+-0.01                       4

5 Mar.          1884.889      10.10                             3
                    .891                     +0.55              2

8 Mar.          1887.903      10.17                             3
                    .903                     +0.63              2


                          [FIGURE 1]

 Figure 1. Magnitude (dots) and color (circled dots) of T CrB
 after the 1946 outburst.

    The transformation from the photoelectric b-y system
to B-V is linear in the range of color variation observed
in T CrB. Delta CrB was the primary comparison star among
the eight observed. The observations were made by G.E. Kron
assisted by H.L. Johnson. The data of Table I are plotted
in Fig. 1 where smaller dots indicate greater uncertainty.



                       KATHERINE C. GORDON

                       GERALD E. KRON

                       Pinecrest Observatory
                       416 N. Bertrand St.
                       Flagstaff, Arizona
                       U.S.A. 86001