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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

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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

Not Available

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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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See detailPhotometry with FORS at the ESO VLT
Freudling, W.; Romaniello, M.; Patat, F. et al

in Sterken, C. (Ed.) The Future of Photometric, Spectrophotometric and Polarimetric Standardization (2007, April 01)

ESO's two FOcal Reducer and low dispersion Spectrographs (FORS) are the primary imaging cameras for the VLT. Since they are not direct-imaging cameras, the accuracy of photometry which can routinely be ... [more ▼]

ESO's two FOcal Reducer and low dispersion Spectrographs (FORS) are the primary imaging cameras for the VLT. Since they are not direct-imaging cameras, the accuracy of photometry which can routinely be obtained is limited by significant sky concentration and other effects. Photometric standard observations are routinely obtained by ESO, and nightly zero points are computed mainly for the purpose of monitoring the instrument performance. The accuracy of these zero points is about 10%. Recently, we have started a program to investigate, if and how percent-level absolute photometric accuracy with FORS can be achieved. The main results of this project are presented in this paper. We first discuss the quality of the flatfields and how it can be improved. We then use data with improved flatfielding to investigate the usefulness of {Stetson standard fields} for FORS calibration and the accuracy which can be achieved. The main findings of the FORS Absolute Photometry Project program are as follows. 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. Percent level photometric accuracy can be achieved with FORS1. To achieve this accuracy, observers need to invest some of the assigned science time for imaging of photometric standard fields in addition to the routine nightly photometric calibration. [less ▲]

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See detailPhotometry, pole orientation and shape parameters of the minor planets 624 Hektor and 43 Ariadne
Detal, Alain ULg; Collette, P.; Hainaut, O. et al

in Brahic, A.; Gérard, J. C.; Surdej, J. (Eds.) "Observations and physical properties of small solar system bodies", 30th Liège International Astrophysical Colloquium, Institut d’Astrophysique, Liège (1992)

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See detailPhoton correlation spectroscopy for molecular self-assembly investigations
Razafindralambo, Hary ULg

Conference (2013, April 11)

The molecular self-assembly performance is among the most important functionalities of amphiphilic compounds in colloidal system areas. This aptitude is required in numerous applications, depending on ... [more ▼]

The molecular self-assembly performance is among the most important functionalities of amphiphilic compounds in colloidal system areas. This aptitude is required in numerous applications, depending on solubilization, hydrotropy, rheology, separation, loading and delivery, encountered in biological and industrial processes. The main physicochemical parameter predicting the capacity of amphiphiles to self-assembly in bulk liquid, aqueous (normal micelles) or non-aqueous phase (reverse micelles), is the pair critical micelle concentration (CMC) and temperature (CMT). A variety of methods based on surface tension, spectral changes, and electrical conductivity are commonly used for determining the value of CMC. The choice usually depends on the ionic or non-ionic nature of the amphiphilic compounds. In this communication, a standard Photon Correlation Spectroscopy (PCS), also known Light Scattering-based technique for CMC determination will be theoretically and practically described in details. Its particular interest for measuring the performance of non-ionic and very high hydrophobic tail, mono or disubstituted carbohydrate-based compounds, from C16 alkyl chain, will be demonstrated. Such a method is advantageous regarding the time, amount, and resolution required, but also for additional information on micelle size, aggregate number, and stability it may provide, compared to surface tension and electrical conductivity-based measurements. [less ▲]

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See detailThe photon wave function
Cugnon, Joseph ULg

in Open Journal of Microphysics (2011), 1

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See detailPhotoperiodic control of testosterone metabolism, plasma gonadotrophins, cloacal gland growth, and reproductive behavior in the Japanese quail.
Balthazart, Jacques ULg; Massa, R.; Negri-Cesi, P.

in General and Comparative Endocrinology (1979), 39(2), 222-35

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