COMMISSION 27 OF THE I. A. U.
         INFORMATION BULLETIN ON VARIABLE STARS
                     Number 1351

                                   Konkoly Observatory
                                   Budapest
                                   1977 October 17




             NOVA SAGITTARII 1975 NO 2




    Nova Sagittarii 1975 No 2 was found on an objective prism
plate taken with the Uppsala Southern Schmidt telescope at Mt
Stromlo (IAU Circ. 2997). Since the plate belongs to a large
survey work, it was unfortunately not searched until more than
a year after the exposure. The only observations of the nova in
the bright phase besides this spectrogram are, as far as we know,
three magnitude measurements made by Huth (IBVS No. 1205) included 
in the Sonneberg Sky Patrol programme. We have also identified 
the star on Palomar Observatory Sky Survey and on Uppsala
Southern Schmidt plates taken during 1977. The position of the
candidate star is
               alpha = 17h46m47.4s +- .4s
               delta =-17d22'30" +- 5"
for the epoch 1950.0, being equal to l =10.39d, b=5.15d, i.e.
close to the direction of the galactic centre. A finding chart
is given in Fig. 1, magnitude observations in Table 1.

                    Table 1

       Year, date    Source                  m_pg
                                    
       1950           Palomar Observatory      15:
                      Sky Survey
       1975 May 12.98 Sonneberg Sky Patrol    >11
       1975 June 1.99 Sonneberg Sky Patrol      9.4
       1975 June 8.69 Uppsala Southern          8.5:
                      Schmidt (prism)
       1975 July 5.92 Sonneberg Sky Patrol    >11
       1977 March 15  Uppsala Southern         15:
                      Schmidt (direct)
    The objective prism spectrogram was scanned with the PDS
machine of Lund Observatory. Unfortunately the spectrum was partly


                          [FIGURE 1]

 Fig. 1. Finding chart for the nova. The side of the field is 10'.
 Visual plate from Uppsala Southern Schmidt Star A is HD 162080
 and star B is BD -17d4926.

                          [FIGURE 2]

 Fig. 2. Filtered density tracing of the nova spectrum. Original
 dispersion is 47 nm/mm.


overlapped with the fainter spectrum of a nearby star, thus
preventing us from using the full width of the spectrogram. Fig. 2
shows a density tracing filtered with a Gaussian numerical filter 
in order to reduce the background noise. The relatively low
original dispersion, 47 nm/mm at Hgamma, does not allow a detailed
identification of the spectral features. The strongest emission
features, besides the Balmer lines, are due to Fe II and Ti II,
and the absorption lines are not very pronounced. This suggests
that the spectrum is of the "diffuse enhanced" type, characteristic 
for a nova about two magnitudes below maximum. Moreover,
a comparison with a series of spectrograms of Nova Cygni 1975
(Lindegren and Lindgren, Nature 258, 501), shows that the spectrum 
very closely resembles the spectrum of Nova Cygni 1.5 magnitudes 
below maximum. The maximum magnitude would then be around
m_pg =7, giving a total amplitude of about 8 magnitudes. This also
implies that the observation on June 1.99 is a premaximum 
observation, and that the maximum brightness occurred one or two days
later. The (negative) observation on July 5.92 puts an upper limit 
on the time for the decline to three magnitudes below maximum,
t_3. It follows that t_3 < 33 days, probably is t_3 considerably
smaller (10 - 20 days). This places the nova in the group of fast
or possibly very fast novae.
   On the basis of the scarce data no reliable values for 
absolute magnitude and distance can be calculated. We would be
very happy to know if there exist any other observations of this
nova during its active stage, since such data could provide a
basis for more firm and reliable conclusions about its properties.





                             INGEMAR LUNDSTROM
                             BJORN STENHOLM

                             Lund Observatory
                             Svanegatan 9
                             S-222 24 Lund, Sweden