GEOS meeting will take place this year at Aras de los Olmos, Valencia, Spain

during  May 31 - June 2 week-end, just after "6th Iberian Meeting on Asteroseismology” (May 27 - 29).

GEOS members are also invited to attend "6th Iberian Meeting on Asteroseismology". The web page of thIs 

event is here. 

Sessions and accommodation for both events will be at Aras Rural

Prices of accommodation and full board are the following:

  1. €60/day in single hotel room.
  2. €50/day in double hotel room.
  3. €50/day in a wooden cottage  (minimum 3 people per cottage; cottages include two double rooms,                                                                                                                 one single room, one bathroom, kitchen, dining room and living room).

E-mail booking is preferred, in Spanish or English, sent to This email address is being protected from spambots. You need JavaScript enabled to view it., with copy to This email address is being protected from spambots. You need JavaScript enabled to view it. and This email address is being protected from spambots. You need JavaScript enabled to view it.

Please state in your mail that you are booking to attend the "GEOS 2013" meeting, or "6th Iberian"+"GEOS 2013" meetings if you are

also attending the Iberian Meeting on Asteroseismology.

To book or request information by phone, in Spanish or English, call +34 639 196 928. If the call is in English, ask for Silvia.

Booking accommodation with copy to This email address is being protected from spambots. You need JavaScript enabled to view it.  and/or This email address is being protected from spambots. You need JavaScript enabled to view it. will confirm

your registration to GEOS meeting.

Registration to  "6th Iberian Meeting on Asteroseismology" can be done on line here.

If your intention is to make a presentation please send title and expected duration as soon as possible to Juan :  This email address is being protected from spambots. You need JavaScript enabled to view it. 

with copy to  This email address is being protected from spambots. You need JavaScript enabled to view it.


   Asterosismology Meeting GEOS
  (May 27 – 29, 2013) (May 31 – June 2, 2013)
Roland Boninsegna   X
Jose Bosch   X
Jaime Busquets   X
Laurent Corp     X
Mercè Correa    X
Juan Fabregat X X
Jean-François Leborgne    (Via Skype)
Raymonde Mat   X
Ramon Moliner    X
Ennio Poretti    X
Luis Rivas     X
Joseph Remis  X X
Jacqueline Vandenbroere   X
Alejandro Vera   X
Josep M. Vilalta             X


Schedule :


Author Title Date & Time Link
Ennio Poretti Stellar Pulsations in the Exoplanet Era 31/05/2013 10:00 MEET012
Juan Fabregat  6th Iberian Meeting on Asterosismology : Identifying seismology targets from H-alpha photometric surveys  31/05/2013 14:00 MEET018
All AVA & University Observatories Visit 31/05/2013 16:00  
Joseph Remis Administration and accounting. 31/05/2013 19:00  
Alejandro Vera & Jose Bosch Observations at Aras de los Olmos AVA observatory 31/05/2013 20:00 MEET011
Jacqueline Vandenbroere Long term variations of RR Lyr periods. 01/06/2013 09:30 MEET014
Laurent Corp Sun SID measurements 01/06/2013 10:30 MEET015
Laurent Corp Eclipsing Binaries: Results and prospects 01/06/2013 12:00 MEET016
Josep M. Vilalta & Ramon Moliner. Nuestros métodos y experiencias en la observación de estrellas variables RR Lyrae. 01/06/2013 16:00 MEET017
Jean-François Le Borgne Skype Participation 01/06/2013 16:00  
Roland Boninsegna How to use the Excel tool to follow RR Lyr period variations. 01/06/2013 17:45 MEET019

We will take the occasion offered by the

"Pro-Am Conference on Stellar Astrophysics"

planned from September 28th to October 1st, 2012 in Onet-Le-Chateau
(close to Rodez,  France), to have our annual GEOS meeting
on the same days.   We could discuss GEOS business on Friday
afternoon and/or Monday afternoon.  We strongly encourage
GEOS members
- to register to the Conference and
- to propose  talks
at the site

The detailed agenda of the GEOS meeting is now as follows :

Rodez, september 28, 2012  14h - 18h

  • 14h : opening by Ennio Poretti
  • 14h10 : Jacqueline Vandenbroere : how to publish new elements of 800 RR Lyrae
  • 14h 45 : Roland Boninsegna  : NP Cam, a new RV Tauri star
  • 15h 30 :  Next GEOS meeting at Aras de los Olmos Spain,  may  2013 ?
  • 16h : coffee break
  • 16h 30 : Jacqueline Vandenbroere : call to collaboration for updating of RR Lyrae elements
  • 17 h : updating of the priority program.

It will also be possible to organize a technical workshop on the time-series analysis
after the Conference, very probably in Toulouse.
The  GEOS members interested in the technical workshop are requested to contact  Jean-Francois Le Borgne and
Ennio Poretti in order to  evaluate the  feasibility.


Following the exercise I made end of august by updating the elements of RR Lyr stars for the schedule of Tarot telescopes, I eventually updated the elements of 347 stars of the GEOS survey.

This is almost the whole sample of 356 stars. I just excluded a couple of stars for which detailed studies are on the way.

The result is in this file.

Most of the stars are RRab stars with the exception of 3 RRc and 2 misclassified cepheids in southern hemisphere. For some stars,new elements are not necessary: for these stars, the reference of the elements are given in the last column of the file. Again, these elements fit the recent observations made during the last decade.

They are intended to be used for predicting maxima in the near future. By the way, I made some statistics : During the last 7 years, after the start of RR Lyr program on the first Tarot telescope, the GEOS RR Lyr Survey collected 6062 CCD maxima on 356 stars.

Apart from the robotic telescopes, Tarot-Calern, Tarot-Chile and Alain Klotz' Faro, the observers who contributed are the following: N. Butterworth, L. Corp, E. Denoux, S. Dvorak, F. Fumagalli, F.-J. Hambsch, F. Hund, D. Husar, J.M. Llapasset, G. Maintz, J. Nicolas, M. Nobile, A. Paschke, P. de Ponthiere, P. Roblin, M. Serrau and F. Van Den Abbeel.

Jean-François Le Borgne






20h00 diner at Auberge des Coupoles






12h30 lunch at Auberge des Coupoles  



20h00 diner at Auberge des Coupoles





  • 10h00 Discussions / Open workshops
    J.F. Le Borgne/all: Discussion+workshop on the use of the RR Lyr wiki
    all: GEOS administration
  • 12h00 end session

12h30 lunch at Auberge des Coupoles.


Guy Boistel, Hélène Boithias , Roland Boninsegna, Merieme Chadid,  Laurent Corp, Mercé Correa, Eric Denoux,

Ghislaine Dine-Zepter, Michel Dumont, Juan Fabregat, Denis Gillet, Jean Gunther, Josch Hambsch, Dieter Husar,

Adrien Klotz, Alain Klotz, Jean-François Le Borgne, Jean-Claude Misson, Anton Paschke, Pierre de Ponthiere,

Joseph Remis, Jean Strajnic,  Jacqueline Vandenbroere, Josep Maria Vilalta.

- VY CrB
After the observations made by Pierre de Ponthiere this year, we are able to show that VY CrB has a strong Blazhko effect (see attached figure: blue points, Pierre de Ponthiere; yellow points, Jean Marie Llapasset). Pierre's measurements combined with those made 3 years ago by Jean Marie and by Anton Paschke 10 years ago, allow to set the Blazhko period to 32 days. More details on the wiki page:

Après les observations faites par Pierre de Ponthiere cette année, nous pouvons affirmer que VY CrB a un fort effet Blazhko (voir la figure attachée: points bleus: Pierre de Ponthiere; points jaunes: Jean Marie Llapasset). Les mesures de Pierre, combinées à celles de Jean Marie d'il y a 3 ans et celles d'Anton Paschke d'il y a 10 ans, permettent de fixer la période Blazhko à 32 jours. Plus de détails sur la page wiki:

- RR Lyr:
The Blazhko effect of RR Lyr is fading as it was observed 50 years ago and as it probably does every 5-10 years ! The observations made by the VTT experiments (L. Corp, E. Denoux, A.+A. Klotz and myself) in 2008 and 2009 shows a variation of maximum O-Cs with an amplitude of about 0.09 day.  In 2010, this amplitude is 0.06 day only . We suspected this fading on the way last year but is confirmed this year. Also, the shapeof the O-Cs curve folded on Blazhko period becomes les and less sharp.
This is shown on the attached figure where the 2008 observations are in grey, the 2009 observations in purple. This year's maxima are shown in different colors corresponding to different Blazhko cycles. See VTT experiments page on the wiki: .

L'effet Blazhko de RR Lyr décroit comme cela a été observé il y a 50 ans et comme cela se produit probablement tous les 5-10 ans ! Les observations faites avec les VTT (L. Corp, E. Denoux, A. Klotz et moi-même) en 2008 et 2009 montrent une variation des O-Cs des maximums avec une amplitude de l'ordre de 0.09 jour. En 2010, cette amplitude n'est plus que de 0.06 jour. Nous soupçonnions cette décroissance l'an dernier déjà, mais elle est confirmée cette année. Également, la forme de la courbe des O-Cs compositée sur la période Blazhko devient de moins en moins piquée. C'est ce que montre la figure attachée où les points de 2008 sont en gris, ceux de 2009 en pourpre. Les maxima de cette année sont en différentes couleurs correspondant aux différents cycles Blazhko. Voir la page des VTT sur le wiki:

- Astropedia :I added a link in the wiki to the thesis of a colleague of mine, Thomas Gastine. His thesis might be of interest for most of us. It concerns the pulsation of cepheids .
The text of the thesis may be downloaded from the Toulouse University library web site.

J'ai ajoute un lien dans le wiki sur la thèse d'un de mes collègues, Thomas Gastine. Sa thèse pourrait intéresser certains d'entre nous. Elle porte sur la pulsation des céphéïdes. .
Le mémoire de la thèse peut être téléchargée depuis le site web de la bibliothèque de l'Université de Toulouse.

- Astropedia : I also included articles about heliocentric correction in the wiki. .

Thesetextes are in English and French. They are also available on the pages

I also made a new design for the astronomical ephemeris

J'ai également introduit des articles sur la correction héliocentrique dans le wiki:

Ces textes sont en anglais et en français. Ils sont également disponibles depuis les pages

Par ailleurs j'ai donné un nouveau look aux calculs astronomiques

I remember that the access to the wiki is open to anybody and to become a redactor one has to request for a login.

L'accès au wiki est ouvert mais pour devenir rédacteur, vous devez demander un login.

Jean-Francois Le Borgne