COMMISSION 27 OF THE I. A. U.
          INFORMATION BULLETIN ON VARIABLE STARS
                       Number 1911
   
                                        Konkoly Observatory
                                        Budapest
                                        1981 January 13

                                        HU ISSN 0374-0676


              FAST PHOTOMETRY OF AE Aqr


     We observed AE Aqr photoelectrically starting at
JED_Hel 2444438.659459 with the 1.6m telescope of the Brazilian
Astrophysical Observatory. Fast photometry (1s integration time)
was carried out in white light during one hour.
     The "16.5s" and "33s" oscillations discovered by Patterson
(1979) are present in our data. Fig. 1 shows the power spectrum
for our observing run.

                        [FIGURE 1]

 Fig. 1.  Power spectrum of AE Aqr. Ordinates are power in bin/mean
          power in the spectrum. The low frequencies were suppressed
          with a high-pass filter.


    We have derived a mean time for the maxima of the "16.5"
oscillations, once the effect of the time delay due to the orbital
motion of the pulsating source during the observation was 
subtracted:

       Max. light at JED_Hel 2444438.659610          (1)
                            	       (+-2)
    Using the ephemeris given by Patterson (1979)

       Max. light at JED_Hel 2443668.915387+1.91416306x10^-4E
                            	        +-3      (+-20)

we found a residue of .569 cycles after 4021309 cycles of the
"16.5s" oscillation. This residue would make the cycle counting
insecure in normal conditions; but AE Aqr displays an additional
feature that we can use: the "main" pulse of the "33s" oscillation 
has always an even cycle number. As it can be seen in Fig. 2,
the first pulse in our observing run is the "main" one, and so,
should have an even cycle number (4021310).  


                     [FIGURE 2]

 Fig. 2. Mean light curve for the "33s" oscillation in AE Aqr.
         Amplitude is given in magnitudes.


   Assuming Pdot to be small enough to be detected yet, a correction
can be set to the period given in (1)

               Best P = 1.91416285 x 10^-4d.
                              (+-4)



                            F. JABLONSKI
                       CNPq/Observatorio Nacional
                       Observatorio Astrofisico
                       Brasileiro

Reference:
Patterson, J. 1979, Astrophys.J. 234, 978 [BIBCODE 1979ApJ...234..978P ]