COMMISSION 27 OF THE I. A. U.
        INFORMATION BULLETIN ON VARIABLE STARS
                     NUMBER 496


                             Konkoly Observatory
                             Budapest
                             1970 December 12


 RESULTS OF THE STUDY OF 3806 VARIABLES IN AND ABOUT THE
                MAGELLANIC CLOUDS

            (presented at IAU, Brighton)

1. Three thousand and five hundred and seventy one stars
  were announced by the Harvard College Observatory in
  the time interval from 1889 until 1953. Two hundred and
  thirty five new variables I found during my work with
  Mrs. Gaposhkin on the Clouds from the year 1960 while
  making more than two million observations on some 4000
  plates. We found that 483 announced variables are probably
  not bona fide variables and they were discarded.

2. The distribution of the variables in and about both LMC
  and SMC finally accepted by Mrs. Gaposhkin and myself in
  reference to eleven classes of variability in light was
  published in 1970. (See No. 420, Inform. Bull. Comm. 27
  of IAU).

3. Employing an accurate formula for 85 eclipsings in both
  Clouds I determined many individual moduli. The mean.
  moduli for the Clouds are

     18.38 +/- 0.02 for LMC and 19.15 +/- 0.03 for SMC

  The corresponding distances and diameters, the latter,
  of course, as seen on the Harvard Bruce plates are:
  47.4kps and 6.9kps;67.79kps and 5.8kps.

4. With these moduli I derived the Absolute Period-Luminosity
   Relation for 2244 Cepheids equally divided between
   two Clouds. For the SMC: M = -2.12m - 2.24m logP. For those
   of the LMC the relation is very much alike; for the
   W Virginis stars it runs parallel 2.40m below. For the
   Long Periodics it is less explicit yet still definite.
   These relations are explicitly for the maximal brightness
   of the lightcurve and not for any other brightness which
   I find from the point of view of application are inferior
   to that adopted here. This P-L relation I'd call the 
   "First Cosmic Law" or Miss Leavitt law.

5. My Topography of the LMC brought forth 34 bright regions
   or "Ridges", not senselessly called associations, in
   contrast to the surrounding regions embracing the whole
   Cloud of lesser density of stars. Many interesting and
   may be significant interreliationships between these
   Ridges, Coils and Variables are indicated.


6. The two-dimensional distribution of all 3323 Variables
   leaves little doubt that the "TILT" of both Clouds
   scarcely can hold the ground. At least not in its 
   conventional sense.

7. Out of many hundreds of miniclusters (the small and the
   smallest clusters of stars hitherto practically unknown
   and not attended though perhaps they form a fundamental
   background of the Clouds) I found partly serendipitiously
   partly with intention that at least twenty of them have 
   variables of all sort making them, at least temporarily,
   a new kind of stellar formations, a new sort of denizens.

8. Turning to account the formulae for the Cepheids, RR
   Lyrae and Eclipsings I was able to  place 119 Variables
   of both Clouds, hitherto a puzzle as a "Surplus" in
   their proper and accurate perspective. They all with a
   few exceptions are located between the Clouds and the
   Milky Way forming "silver cords" suggesting or recommending
   the stellarly physical connection between these starry
   families MW, LMC, LMC probably reminiscent of NGC6027.

9. If No. 8 is correct however imperfectly  and deficiently
   presented then the "strange" findings of Miss Cannon
   years ago and the very recent ones of Fehrenbach and
   Duflot in reference to foreground stars are no more
   strange but "natural".

10. Two thousand five hundred and forty seven periods of
    Variables were determined in this work independent of
    the old work at the HCO with an exception  of using the
    announcement and identification. Three fifths of the
    periods are quite new, the rest redetermined to a higher
    accuracy.

11. In historical sense our work constitutes a finalizing
    of a probably most expensive astronomical project at
    the HCO and certainly the longest project for it began
    in the very beginning of modern astronomy and lasted
    81 years, one month and seven days counting the end the
    date of my signature of this article. The project is
    undoubtedly also the greatest ever emprized by a single
    observatory.

    December 1, 1970                 

                           SIRGAY GAPOSHKIN
                      Harvard College Observatory