VX Hya time keeping. Stroboscopic analysis [Observed: 2005-21]
Photometric observations of the double-mode pulsator VX Hya are presented. They are analyzed with a stroboscopic method, completed by Fourier analysis.

AR Ser: photometric observations of a Blazhko star [Observed: 2010-2014]
Photometric observations in 2010-2014 of the RR Lyrae star AR Serpentis are presented and analyzed. Two Blazhko modulations of comparable amplitude are detected, with the periods 89 and 108 days, and with evidence for irregularities.

KV Cnc []
Photometric observations of this Blazhko star are presented and analyzed.

VX Hya (2011-2012 season) [Observed: 21, 22, 27 Feb, 13 Mar 2012]
Time-series are presented for this pulsating star, after its sudden pulsation change in 2008 and after the 2010-2011 season observations.

RV Cet: a Blazhko pulsating star [Observed: 26 sessions in 2009-2011]
Photometry observations of this RRAB pulsating star are presented, with a GIF animation showing the Blazhko modulation.

VX Hya (2010-2011 season) [Observed: 5, 7, 8 Feb, 4 Mar, 9 Apr 2011]
Time-series are presented for this pulsating star, after its sudden pulsation change in 2008.

VX Hydrae: observation of a sudden change in a pulsating star [Observed: March 2005-April 2010]
Time-series of VX Hya from March 2005 to April 2010 are analyzed. A period jump is discovered to happen in 2008 in all the pulsation modes, being at its strongest for the overtone.

VX Hya (2008-2009) phase variations [Observed: 24, 27, 28 Dec 2008, 29, 30 Jan, 17, 19, 22, 23 Mar 2009]
The strong phase shift that I detected in 2008 is confirmed with new observations.

UX Mon: time keeping and modelling of a binary [Observed: 13 Dec 2007, 11-16, 18 Feb, 8, 13, 14 March, 1, 4, 25, 29]
Time series of this eclipsing binary system with extra variability are presented. The O-C analysis suggests the presence of a third star. The observations are modelled with BinaryMaker3 and parameters of the system are derived.

1RXS J180834.7+101041: a new cataclysmic variable with a nearby RRAB variable [Observed: 2, 3, 5 Aug 2008]
Time-series for this recently discovered cataclysmic variable and for a nearby RR Lyrae variable are presented.

VX Hya (2008) free fall? [Observed: 7-13 Feb 2008]
Time-series for this pulsating star with multiple oscillations are obtained. They are compared with the ephemeris of Fitch (1966): they are too early by 3.7 hours. This is a strong change from previous, recent observations.

VX Hya long term variability [Observed: 24, 25, 26, 27 Dec 2006]
Time-series for this pulsating star with multiple oscillations are obtained. They are compared with the ephemeris of Fitch (1966): there is a delay of 1.2 hour. I also compile various observations and derive an O-C diagram from 1954 to 2007.

EH Lib: 2007 follow up [Observed: 24 Apr, 7, 12 July 2007]
Time-series of this DSCT pulsating star with a period of 2.1h are presented and compared with 2004-2005 observations.

KU Her: a slow irregular variable [Observed: 12, 13, 14, 15, 19 July, 5, 18 Aug, 5, 6, 12, 15, 19, 20 Sept,]
Multicolor photometry of this irregular variable star are presented.

ASAS1826+12: the eclipsing Cepheid [Observed: 7, 12, 13, 14, 15, 17, 19 July, 5, 18 Aug, 5, 6, 12, 15, 19,]
Multicolor photometric measurements of this Cepheid in an eclipsing binary system (the only known one in our galaxy) are presented.

TX Mon: a Cepheid radius variations [Observed: 23 sessions from 29 Mar 2006 to 11 Mar 2007]
B,V photometry measurements of this Cepheid are presented. The distance, temperature and radius of this pulsating star are computed.

SZ Mon, the double pulsator [Observed: 35 sessions from 23 Dec 2005 to 11 Mar 2007]
Photometry of this pulsating supergiant star (33d period) are presented. The magnitudes are compared with published observations. The measurements are also corrected for a nearby star. Variations of the color, temperature, radius and luminosity are inferred.

SZ Mon: very low resolution spectroscopy (experiment) [Observed: 16, 30 Oct, 24, 28 Dec 2006, 12, 13 Jan 2007]
I observed this pulsating supergiant with a slitless 100groves/mm transmission grating, trying to see the variations of the spectra as a function of the pulsational phase.

KZ Hya: a pulsating binary (improved) [Observed: 9 Feb, 11, 14 March, 19 Apr 2007]
This pulsating star is in a binary system with an 8-yr orbital period. The times of maximum are compared with an improved ephemeris and the parameters of the binary are derived.

KZ Hya: a pulsating binary [Observed: 23, 24 Dec 2005, 25 Jan, 13 Mar, 7 Apr 2006]
Time-series of this pulsating SXPHE star in a binary system are presented and compared with other observations.

Pulsating stars I: Differential equation []
The differential equation of a radially pulsating star is derived.

Pulsating stars II: Solutions at constant density []
The differential equation for a radially pulsating star is solved for a constant density.

Pulsating stars III: Polytropic model []
The solutions to the differential equation of a radially pulsating star are presented for a polytropic model.

W Vir: temperature, radius and radial velocity determinations from B, V photometry [Observed: 16 observing sessions from 27 April to 20 July 2005]
V and B magnitudes measurements are obtained for this Population II Cepheid pulsating star. They are used to compute the variations of temperature, radius and radial velocity. The results are compared with direct measurements from spectroscopy.

KZ Hya time keeping [Observations: 25, 27 April, 18, 19 May 2004]
Three pulses are observed for this SX Phe pulsating star. They are 29 mn late from the 29 yr old GCVS ephemeris.

VX Hya time keeping [Observations: 10, 11, 13, 16, 17, 18 March 2005]
Time-series for this pulsating star with multiple oscillations are obtained. They are compared with the Fitch (1966) ephemeris: the matching is still good but with a delay of 1.4 hour.

TV Lib: temperature and radius variations from photometry [Observations: 11, 13, 17, 18 March 2005]
Two-color time-series were obtained for this pulsating RR Lyrae star. The pulsation is too early when compared with the ephemeris. The temperature and the radius variations are computed from different models.

EH Lib regular pulses [Observations: April-May 2004, March-April 2005]
The pulsating star EH Lib was observed and 15 pulses were measured. They are in phase with the 55-year old ephemeris of the GCVS (may be late by 2 or 3 mn only).