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See detailPhotometric variability of southern CP stars
Manfroid, Jean ULg; Mathys, G.

in Astronomy and Astrophysics. Supplement Series (1986), 64

The photometric behavior of eight southern CP stars with relatively large amplitudes of variation is analyzed. Periods of variation and parameters of the light curves are obtained by least-squares fitting ... [more ▼]

The photometric behavior of eight southern CP stars with relatively large amplitudes of variation is analyzed. Periods of variation and parameters of the light curves are obtained by least-squares fitting. A wide variety is found in the periods and in the shapes of the light curves, confirming the lack of correlation between these parameters and the amplitudes. [less ▲]

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See detailPhotometric variations and period of the spectrum variable HR 3413.
Renson, Pierre ULg; Heck, A.; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1978), 31

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1978A&AS...31..199R

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See detailPhotometric variations in Ap stars observable at La Silla in November and December
Renson, Pierre ULg; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1981), 44

Photometric observations of 13 Ap stars made at the European Southern Observatory at La Silla during November 1977 and December 1978 are reported. Observations were made in the uvby with the four-channel ... [more ▼]

Photometric observations of 13 Ap stars made at the European Southern Observatory at La Silla during November 1977 and December 1978 are reported. Observations were made in the uvby with the four-channel photometer at the 40-cm telescope in November, and with the one-channel photometer at the 50-cm telescope in December. Light variations with periods from 0.724 to 4.64 days are obtained for 11 of the stars, including the Hg-Mn star HR 2202, which was believed not to vary. Extremely small variations are observed in Upsilon 4 Eri, with a possible period of 0.51 days, although the two Mn components are likely to vary independently. HR 1800 was not observed to vary over two-week observation period. The stars 20 Eri, HR 1194, Alpha Dor, 11 Ori and HD 36916 are also noted to exhibit relatively large variations for Ap stars. [less ▲]

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See detailPhotometric variations of 46 Eridani and 210 G. Eridani
Manfroid, Jean ULg; Renson, Pierre ULg

in Astronomy and Astrophysics (1989), 223

The photometric behavior in the uvby system of the Ap star 46 Eri is analyzed on the basis of new data. The revised period is P = 3.798777 + or - 0.000015 d. Knowledge of the accurate light-curve of 46 ... [more ▼]

The photometric behavior in the uvby system of the Ap star 46 Eri is analyzed on the basis of new data. The revised period is P = 3.798777 + or - 0.000015 d. Knowledge of the accurate light-curve of 46 Eri makes it possible to refine data on the multiperiodic B5III variable star 210 G. Eri, which was used as a comparison for 46 Eri. Four periods, all of the order of four days, are found with P(1) = 3.9215 d standing out clearly. This value is very large compared to those of other mid-B variables. [less ▲]

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See detailPhotometric variations of Ap stars
Manfroid, Jean ULg; Renson, Pierre ULg

in Astronomy and Astrophysics (1994), 281

The photometric variations of seven Ap stars have been analyzed from observations mainly obtained in the framework of the Long-Term Photometry of Variables project at European Southern Observatory (ESO ... [more ▼]

The photometric variations of seven Ap stars have been analyzed from observations mainly obtained in the framework of the Long-Term Photometry of Variables project at European Southern Observatory (ESO). New values for the periods and detailed light curves in the uvby system are provided. Alpha Scl is shown to display anomalous variations that set it apart from the other stars. [less ▲]

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See detailPhotometric variations of HD 25267
Manfroid, Jean ULg; Mathys, G.; Heck, A.

in Astronomy and Astrophysics (1985), 144

Two periodicities are found in the photometric variations of HD 25267. One of the periods (1.2 d) seems to be the same as the magnetic period and is thus attributed to a CP component. The origin of the ... [more ▼]

Two periodicities are found in the photometric variations of HD 25267. One of the periods (1.2 d) seems to be the same as the magnetic period and is thus attributed to a CP component. The origin of the variations with the second period (3.8 d) remains uncertain. [less ▲]

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See detailPhotometric variations of some Ap stars.
Renson, Pierre ULg; Manfroid, Jean ULg; Heck, A.

in Astronomy and Astrophysics. Supplement Series (1976), 23

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1976A&AS...23..413R

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See detailPhotometric variations of southern Ap stars.
Renson, Pierre ULg; Manfroid, Jean ULg

in Astronomy and Astrophysics. Supplement Series (1978), 34

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1978A&AS...34..445R

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See detailThe photometric variations of the Ap star HD34631
Manfroid, Jean ULg; Renson, Pierre ULg; Catalano, F. A. et al

in Astronomy and Astrophysics. Supplement Series (1991), 90

The photometric behavior in the uvby system of the Ap star HD34631 has been reanalyzed on the basis of data collected over a time span of 16 years. A more accurate value of the period is deduced: P = 2 ... [more ▼]

The photometric behavior in the uvby system of the Ap star HD34631 has been reanalyzed on the basis of data collected over a time span of 16 years. A more accurate value of the period is deduced: P = 2.20269 +/-0.00004d. The lightcurves show a double-wave shape. The variations are smallest in the v band. [less ▲]

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See detailPhotometric Variations of the B6 Star HR 3440
Renson, Pierre ULg; Sterken, C.

in Information Bulletin on Variable Stars (1977), 1373

Not Available

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See detailPhotometric variations of the irregular variable V348 SGR
Heck, A.; Houziaux, Léo ULg; Manfroid, Jean ULg et al

in Astronomy and Astrophysics. Supplement Series (1985), 61

The authors report visual estimates and photometric observations in various wavelength ranges of the irregular variable V348 Sgr. They cover dramatic drops of brightness (from V â 12.5 to â 18) which ... [more ▼]

The authors report visual estimates and photometric observations in various wavelength ranges of the irregular variable V348 Sgr. They cover dramatic drops of brightness (from V â 12.5 to â 18) which occurred in 1972, 1973 and 1981 with a time scale much shorter than the characteristic time mentioned by previous observers. These deep minima are, to our knowledge, the best followed up to now. The maximum brightness of the object seems also to correspond to V â 12 and not 10.5 as reported earlier. The minima reach V â 18, but this might represent the nebular contribution while the star itself might even go fainter. The main conclusions of this compilation are probably that the characteristic times given by Herbig (1958) from appearances on Harvard plates are most likely incorrect and that it is impossible to give one at all. The field of V348 Sgr has also been observed in the uvby system and a sequence is provided in this paper. [less ▲]

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See detailPhotometry of comet Austin.
Manfroid, Jean ULg; Bouchet, P.; Gouiffes, C.

in The Messenger (1990), 59

Strömgren photometry of Gomet Austin (1989 c 1) has been obtained at La Silla with the ESO-SAT 50-cm telescope, between February 12 and February 25, 1990. Two diaphragms were selected, 35 arcsec and 240 ... [more ▼]

Strömgren photometry of Gomet Austin (1989 c 1) has been obtained at La Silla with the ESO-SAT 50-cm telescope, between February 12 and February 25, 1990. Two diaphragms were selected, 35 arcsec and 240 arcsec, in an attempt to distinguish between the nucleus and the coma. [less ▲]

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See detailPhotometry of comets
Sterken, C.; Manfroid, Jean ULg

in Proceedings International Halley Seminar, p. 103, 1987. (1987)

Not Available

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See detailPhotometry of HR 3413.
Renson, Pierre ULg; Sterken, C.

in IAU Archives of unpublished observations of variable stars file number :, 55, 1 (1977) (1977), 55

Not Available

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See detailPhotometry of p/ Halley 1982I
Sterken, C.; Manfroid, Jean ULg; Arpigny, Claude ULg

in Astronomy and Astrophysics (1987), 187

Abstract image available at: http://cdsads.u-strasbg.fr/abs/1987A&A...187..523S

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See detailPhotometry of southern stars in the uvby system.
Manfroid, Jean ULg

in Bulletin de la Société Royale des Sciences de Liège (1980), 49

Not Available

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See detailPhotometry of the G8V Star HD 192020
Vreux, Jean-Marie ULg; Manfroid, Jean ULg

in Information Bulletin on Variable Stars (1985), 2822

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See detailPhotometry of the Wolf-Rayet Star HD 191765
Vreux, Jean-Marie ULg; Manfroid, Jean ULg

in Information Bulletin on Variable Stars (1985), 2821

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See detailPhotometry with FORS
Freudling, W.; Møller, P.; Patat, F. et al

in Kaufer, A. (Ed.) The 2007 ESO Instrument Calibration Workshop (2008)

Photometric calibration observations are routinely carried out with all ESO imaging cameras in every clear night. The nightly zeropoints derived from these observations are accurate to about 10%. Recently ... [more ▼]

Photometric calibration observations are routinely carried out with all ESO imaging cameras in every clear night. The nightly zeropoints derived from these observations are accurate to about 10%. Recently, we have started the FORS Absolute Photometry Project (FAP) to investigate, if and how percent-level absolute photometric accuracy can be achieved with FORS1, and how such photometric calibration can be offered to observers. We found that there are significant differences between the sky-flats and the true photometric response of the instrument which partially depend on the rotator angle. A second order correction to the sky-flat significantly improves the relative photometry within the field. We demonstrate the feasibility of percent level photometry and describe the calibrations necessary to achieve that level of accuracy. [less ▲]

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