ADS BibCode:
1983Msngr..33....1B
Author(s)/Affiliation(s):
Behr, A.
AA(ESO)
Abstract:
Otto Heckmann, past Director General of the European Southern Observatory (1962-1969), President of the International Astronomical Union (1967-1970), and the Astronomische Gesellschaft (1952-1957), Professor of Astronomy and Director of the Hamburg Observatory (1941-1962), died on May 13, 1983.

ADS BibCode:
1983Msngr..33....2D
Author(s)/Affiliation(s):
D'Odorico, S.; Enard, D.; Lizon, J. L.; Ljung, B.; Nees, W.; Ponz, D.; Raffi, G.; Tanne, J. F.
AA(ESO) AB(ESO) AC(ESO) AD(ESO) AE(ESO) AF(ESO) AG(ESO) AH(ESO)
Abstract:
In the first tests at La Silla, CASPEC, coupled with a CCD detector, proved to be a promising instrument for high dispersion work on faint objects.

ADS BibCode:
1983Msngr..33....3.
Author(s)/Affiliation(s):
ESO
AA(ESO)

ADS BibCode:
1983Msngr..33....5.
Author(s)/Affiliation(s):
ESO
AA(ESO)

ADS BibCode:
1983Msngr..33....7W
Author(s)/Affiliation(s):
Weiss, W. W.; Schneider, H.
AA(Institute for Astronomy, University of Hawaii and University of Vienna; Max-Kade Fellow) AB(University Observatory Göttingen)
Abstract:
It has been known for many centuries that one can determine by simple means if a barrel of wine is full, half empty, or- horribile dictu - empty. One knocks against the wall and listens to the echo. Another example of the same technique, but less interesting for the connaisseur en vin is given by seismology. Seismographs distributed all over the globe register earthquakes and since they are differently located with respect to an earthquake centre the registrations look different. From a comparison of such registrations geologists have extracted most of our knowledge about the structure and composition of the terrestrial interior. Corresponding experiments were also planned and successfully executed on the Moon and on Mars. Stellar astronomers, however, are not in the lucky position of their colleagues who work in our solar system with the help of satellites. They are limited to stars which pulsate voluntarily. We will not discuss here the question why some groups of stars pulsate and others do not. We shall only mention that pulsating stars have at least one layer in their interior which does not absorb pulsational energy, as is the case for the rest of the star, but produces energy of variable amount and in phase with PUlsation. This mechanism keeps the star pulsating as long as this (these) layer(s) exists. Oue to stellar evolution, diffusion, magnetic fields, to name only some possible mechanisms, these layers can disappear or undergo substantial changes so that the energy losses due to pulsation cannot be compensated anymore. Oamping will result and finally the star will become stable against pulsation.

ADS BibCode:
1983Msngr..33....9S
Author(s)/Affiliation(s):
Swings, J. P.
AA(ESO)

ADS BibCode:
1983Msngr..33...10S
Author(s)/Affiliation(s):
Sterken, C.
AA(Astrophysical Institute, Vrije Universiteit Brussel)
Abstract:
Many visiting astronomers at ESO are involved in the study of stellar variability on long time-scales (supergiants, Ap stars, pre-main-sequence stars ...). Real "monitoring" of variables during a time-span of several years is almost impossible because allotted observing runs are too short and not continuous. The long gaps between the visits of an individualobserver inevitably affect the homogeneity of the results (e. g. effects of changes in the instrumental system). A possible solution towards a more successful study of long-period variables is to select a restricted number of interesting objects of different type, and to observe them in an almost continuous way throughout succeeding observing seasons. Such an observing programme evidently calls for international collaboration in a well-organized team.

ADS BibCode:
1983Msngr..33...11W
Author(s)/Affiliation(s):
Wolf, B.; Stahl, O.
AA(Landessternwarte Heidelberg) AB(Landessternwarte Heidelberg)
Abstract:
Back in 1897, E.C. Pickering reported on the variable star S Dor in the Large Magellanie Cloud (LMC). A quarter of a century later, J.C. Duncan (1922) and M. Wolf (1923) independently diseovered a few variable stars in M 33. Since the extragalactic nature of these galaxies was not yet established in those days (i. e. their distanees were not known) these authors could not realize that they had discovered some of the most luminous variables of the Universe with absolute visual magnitudes brighter than Mv = -9 Thirty years later, in 1953, Hubble and Sandage investigated these stars, nowadays called Hubble-Sandage variables or SOor variables, in more detail. Their main characteristics are: (1) extremely high luminosity (L = 10^6 L), (2) spectral types: early B to F, (3) strong ultraviolet excess (U-B &let -0.8) and infrared excess, and (4) variations of more than one magnitude in the visual spectral range on timescales of years to decades.
References:
Conti, P. S.: 1976, Mem. Soc. Roy. Sei. Liege 9,193.
Dunean, J. C.: 1922, Publ. Astron. Soc. Pacific 34, 290.
Hubble, E., Sandage, A.: 1953, Astrophys. J. 118, 353.
Humphreys, R. M., Davidson, K.: 1979, Astrophys. J. 232,409.
Lamers, H. J. G. L. M.: 1981, in "Effeets of Mass Loss on Stellar
Evolution", lAU Coll. No. 59, Eds. Chiosi and Stalio.
Mendoza, E.: 1970, Bol. Obs. Tonantzintla Tacubaya 5, 269.
Piekering, Z. C.: 1897, Harvard Cire. No. 19.
Walborn, N. R.: 1977, Astrophys. J. 215,53.
Wolf, S., Stahl, 0.: 1982, Astron. Astrophys. 112, 111.
Wolf, M.: 1923, Astron. Nachr. 217, 475.

ADS BibCode:
1983Msngr..33...15E
Author(s)/Affiliation(s):
Encrenaz, T.; Pedersen H.; Tarenghi, M.
AA(Observatoire de Paris,) AB(ESO) AC(ESO)
Abstract:
As mentioned already in the last issue of the Messenger, a very exciting comet crossed the Earth's neighbourhood a few months ago. First discovered by the infrared satellite IRAS, then by two amateurs, Araki (Japan) and Alcock (UK), this comet approached the Earth with a minimum distance of 0.03 AU on May 12, 1983. The previous record of such a minimum distance was in 1770 with Comet Lexeil.

ADS BibCode:
1983Msngr..33...16P
Author(s)/Affiliation(s):
Perrier, C.
AA(ESO)
Abstract:
Our speckle system was implemented in late 1979 on the 3.6 m telescope. Although at that time every component was in a preliminary state, we could record results useful enough to prove the feasibility of such a high spatial resolution instrument. The astrophysically usable results came later in 1981 together with sensitivity gain of the IR photometer (Perrier, 1981, The Messenger No. 25, p. 26). Since then we have entered a period of studies of specific astrophysical targets, some of which will be reported in this article.

ADS BibCode:
1983Msngr..33...19L
Author(s)/Affiliation(s):
Lunel, M.; Bergeat, J.
AA(Observatoire de Lyon) AB(Observatoire de Lyon)
Abstract:
The light curves of close (eclipsing) binaries are not flat between eclipse intervals, due to proximity effects (tidal distortlon, light reflection on facing hemispheres). The separation of the two components is so small in W UMa systems that Continuous variations are observed in the light curves. Minima are nearly equal (see fig. 1) which means similar colours and effective temperatures for both components (spectral types A to K). They are also spectroscopic binaries. Individual masses and radii of the components can be derived in the most favourable cases. Apparently, they prove to be dwarf stars not too far from the main sequence.
References:
Binnendijk, L. 1965, 3rd Colloquium on Variable Stars, Bamberg, p. 36.
Binnendijk, L. 1970, Vistas in Astronomy 12, 217.
Cousins, A. W., and Cox, A. N. 1950, Monthly Notices Astron. Soc. S.
Africa, 9, 90.
Cousins, A. W. 1964, Monthly Notices Astron. Soc. S. Africa 23, 24.
Dineseu, R., and Dumitreseu, A. 1970, St. Cerc. astron. Bucaresti,
val. 15, No. 1, 65.
Hernandez, C. A. 1972, Astronomical Journal 77, 152.
Huang, S. S. 1956, Astronomical Journal 61, 49.
Knipe, G. E. 1967, Rep. Obs. Johannesburg Cire. No. 7, 148.
Tapia, S. 1969, Astronomical Journal 74, 533.

ADS BibCode:
1983Msngr..33...21B
Author(s)/Affiliation(s):
Breysacher, J.; Lequeux, J.
AA(ESO) AB(Observatoire de Marseille)
Abstract:
Surveying in extended lield objects which are recognizable only by their spectral leatures would be an almost impossible task without instruments having simultaneously a wide lield and some spectral discrimination capabilities. Monochromatic imaging with colour or interference lilters offers such a means, which has been widely used lor searching lor H11 regions and planetary nebulae in the Galaxy and in external galaxies. An alternative method is to use objective prisms or transmission gratings which supply for each object in the lield 0f the telescope a spectrum, usually recorded on a photographie plate. However, the difficulties involved in manufacturing very large gratings or prisms, limit this method to telescope diameters 01 about 1 metre, the approximate size 0f the largest eXisting Schmidt telescopes. Fortunately, there is a variant 01 this set-up adapted to larger telescopes, in which a prism, or a grating, or a combination 0f both is inserted in the converging lightbeam at a short distance 0f the local plane. These devices, Usually litted on the prime focus adapter, are called GRISMs or GRENSes. A GRISM combines a transmission grating and a prism with opposed dispersion to compensate the aberrations (coma, astigmatism and lield curvature) produced by the Wating in the convergent beam, and is associated with a wideheld corrector. A GRENS has a grating grooved on one lace 01 the last lens of a wide field corrector, and also has minimal aberrations. Both are blazed such that most of the light is concentrated in the first order. The GRISM technique has already been widely used to search for quasars through their emission lines, mainly at the Cerro Tololo Inter-American Observatory (Hoag and Smith, 1977, Astrophysical Journal 217,362; Osmer, 1982, Astrophys. J. 253, 28), and at La Silla for the detection of carbon and M stars in nearby galaxies (Westerlund, The Messenger No. 19, December 1979, p. 7).

ADS BibCode:
1983Msngr..33...25H
Author(s)/Affiliation(s):
Houziaux, L.
AA(Institut d'Astrophysique, Liege, Belgium)
Abstract:
V 348 Sagitarii is one of the many variables discovered by Miss Ida Woods on Harvard plates (Harvard Bulletin 838, 1926). Later, in the 1950s, 500 patrol plates have been scrutinized by Mrs. Jean Haies Anderson (Hoffleit, Astronomical Journal, 63, 78, 1958) at Maria Mitchell Observatory. This material covered the period 1906-1939 and the derived light Curve suggested a semi-regular variability with cycles of 200 to 400 days. Because of the resemblance of its light curve with the ones of stars undergoing at irregular intervals sudden drops of brightness before recovering more slowly their previous magnitude, that star was once classified as belonging to the R Coronae Borealis type by Schjan, who rediscovered the star in 1929 and gave it the number 3976 in the H(amburg) V(ariables) catalogue (Astronomische Nachrichten, 235, 417, 1929). V 348 Sgr, however, is seen more often at minimum light than at maximum, contrarily to the R Coronae Borealis stars. These objects are known to be carbon rich and this is indeed the case for V 348 Sgr; however, as shown first by George Herbig (Astrophysical Journal, 127, 312, 1958) the spectrum, unlike the other stars of the type reveals the presence of a hot diluted atmosphere around the star where many lines of ionized atoms of carbon are seen instead of absorption bands due to molecular compounds. So both by its light curve and by its spectrum V 348 Sgr is indeed a peculiar object.

ADS BibCode:
1983Msngr..33...26E
Author(s)/Affiliation(s):
Eckert, W.; Muller, A.
AA(ESO) AB(ESO)
Abstract:
A new guider for the ESO 1 m Schmidt telescope was installed inside the telescope tube in June-July 1982. After about one year experience one can say that the system has proved to be very efficient. This device may be useful for other Schmidt telescopes where long exposures are hampered by guiding problems. Historically, the ESO Schmidt was equipped with two guiding telescopes of 20 cm diameter and 300 cm focallength. However, differential flexure between guiders and camera made long exposures impossible. Only a one-hour exposure, symmetrical with respect to the observer's meridian and using a low resolution 103 a-O or II a-O emulsion, was the very best one could obtain. To improve guiding conditions, two off-set guiders were constructed in succession and each one was used for a sufficiently long time to learn the requirements for an efficient off-set system. The new guider has its guide probe in the observer's meridian and at the North edge of the photographic plate. At this position the corrector plate is not vignetted by the main mirror's edge

ADS BibCode:
1983Msngr..33...28.
Author(s)/Affiliation(s):
ESO
AA(ESO)

ADS BibCode:
1983Msngr..33...29F
Author(s)/Affiliation(s):
Fossat, E.; Decanini, Y.; Grec, G.
AA(Observatoire de Nice,) AB(Departement d'Astrophysique de I'I.M.S.P., Nice),AC(Departement d'Astrophysique de I'I.M.S.P., Nice)
Abstract:
Solar seismology (or helioseismology) was born in 1975. Since that recent date it provided the first unambiguous information regarding the internal structure of the sun.
References:
Christensen-Dalsgaard, J., and Frandsen, S.: 1983, Solar Phys. 82,
469.
Decanini, Y.: 1983, These de Specialite, Universite de Nice.
Fossat, E., Decanini, Y., and Grec, G.: 1983, Instrumentation for
Astronomy with Large Telescopes, C. A. Humphries, ed. Reidel.
Grec, G., Fossat, E., and Pomerantz, M.: 1983, Solar Phys. 82,55.
Rhodes, E., and Ulrich, R.: 1982, "Pulsations in classical and cataclysmic
variable stars", 147, J. Cox and C. Hansen, eds. J.I.L.A.

ADS BibCode:
1983Msngr..33...30O
Author(s)/Affiliation(s):
Oliva, E.; Moorwood, A. F. M.
AA(ESO) AB(ESO)
Abstract:
This bright nova was discovered in January 1983 by Liller (1983, lAU Circular No. 3764), just before our scheduled infrared observing runs at the ESO 3.6 m and 1 m telescopes during which we were able to both monitor it photometrically between 1.2 um and 10 I-tm and obtain low resolution 1.4-4.2 um spectra. A detailed description and analysis of these data will be contained in an extensive paper combining ultraviolet, optical and infrared observations, which is now being prepared mostly by J. Krautter. As, to our knowledge, no previous infrared spectra of novae between 1 um and 2 um have been published, we would like to make use of this short article to report the discovery of a strong but broad emission feature at 1.56 um which we can best explain at the moment as an unresolved group of recombination lines to He 11, OV and NV - species normally associated with UV rather than IR spectroscopy

ADS BibCode:
1983Msngr..33...31M
Author(s)/Affiliation(s):
Maceroni, C.; Milano, L.; Nesci, R.; Russo, G.
AA(Monte Mario Astronomical Observatory,Rome) AB(Institute of Physics, Naples University) AC(Institute of Astronomy,Rome University) AD(Capodimonte Astronomical Observatory, Naples)
Abstract:
W UMa binary stars represent a typieal case of astronomieal objects for which theory and teehniques of data reduetion are much more developed and up to date than observations. While the analysis of photometrie observations by means of synthetic light curve methods (Wilson and Oevinney, 1971 Astrophysical JOurnal, 166, 605) yields good photometrie elements, the absence of reliable spectroscopie data makes the determination 0f the absolute elements 0f these systems and therefore of their evolutionary status problematic.

ADS BibCode:
1983Msngr..33...32E
Author(s)/Affiliation(s):
Enard, D.; Lund, G.; Tarenghi, M.
AA(ESO) AB(ESO) AC(ESO)
Abstract:
During a 6-day test period late in November 1982, a prototype optical fiber device (nicknamed "Fiber Optopus") was tested at the 3.6 m telescope Cassegrain focus. The principle of this device, described in more detail in the following paragraphs, is such that the light from up to 50 randomly separated points on the sky (within the Cassegrain focus field of view) can be simultaneously guided via separate flexible optical fibers to the entrance slit of the B&C spectrograph. By making use of a two-dimensional detector such as a CCO the individual spectra, corresponding to each sampled point on the field, can be recorded simultaneously. When fully operational, the Fiber Optopus should enable a very strong reduction in telescope time to be achieved in observing programmes involving low resolution spectral mapping of extended fields. This feature will be of great interest to astronomers wishing to observe clusters of faint objects requiring long integration periods.

ADS BibCode:
1983Msngr..33...32.
Author(s)/Affiliation(s):
ESO
AA(ESO)

ADS BibCode:
1983Msngr..33...37V
Author(s)/Affiliation(s):
van Gorkom, J. H.; Kotanyi, C. G.; Tarenghi, M.; Veron-Cetty, M. P.; Veron, P.
AA(NRAO, Socorro, New Mexico) AB(ESO) AC(ESO) AD(ESO) AE(ESO)
Abstract:
The centre of most Seyfert galaxies contains a radio source with sizes ranging from a few hundred to a few thousand parsees. Optical forbidden lines are generated in regions of similar sizes. Discrete optical line-emitting clouds have also been observed in these regions in some of the nearby Seyfert galaxies.
References:
(1) Ulvestad, J. S., Wilson, A. S., and Sramek, R. A. 1981, AstrophysicalJourna/
247,419.
(2) Veron, M.-P., Veron, P., Tarenghi, M., and Grosb01, P. 1982, The
Messenger 28, 13.
(3) Vorontsov-Veljaminov, B. A., and Ivanisevic, G. 1974, Soviet
Astronomy 18,174.
(4) Wright, A. E. 1974, Monthly Notices of the Royal Astronomical
Society 167,273.
(5) Rubin, V. C. 1980, Astrophysical Journal 238, 808.

ADS BibCode:
1983Msngr..33...39.
Author(s)/Affiliation(s):
ESO
AA(ESO)