17 October 2010

European Variable Star Conference

European Variable Star Meeting
Universiteitsmuseum Groningen, the Netherlands
October 22-24, 2010

vlag_NLD Dutch version




The location
The climate
Meeting registration
Call for presentations
Further information


The Dutch Variable Star Association (WVS-KNVWS) is founded on October 23, 1960. In 2010 the WVS-KNVWS exists for 50 years. We would like to celebrate this milestone with our friends from Europe and far beyond with an European Variable Star Meeting. This meeting will take place in the weekend from Friday October 22 until Sunday October 24, 2010. From the beginning the work of the WVS-KNVWS is supported by the Kapteyn Institute of the University of Groningen. For this reason we will keep this meeting in the beautiful historic university of Groningen.

During this meeting you will meet variable star observers from all over Europe and even from beyond. You can renew old friendships and meet new friends, exchange experiences and learn from each other. Further there will be an interesting program. You will be informed about the latest discoveries in variable star astronomy, the latest observation techniques and latest technological developments that will have an impact on our hobby. You are more than welcome to contribute in the program, for instance by doing a presentation in the program or a poster presentation during the breaks.
We will organize the following special activities during the meeting.
On Friday afternoon the meeting will start with a colloquium followed by an informal reception and a visit to the Blaauw Observatory of the Kapteyn Institute. On Saturday evening there will be a diner and on Sunday afternoon an excursion to Eise Eisinga's Planetarium in Franeker or an excursion to the radio observatory of Westerbork (pending the weather). Several professional astronomers will give a presentation.

The following astronomers already confirmed their presence:
  • Prof. Dr. Adriaan Blaauw (former director of the Kapteyn Institute Groningen, former director of the European Southern Observatory in Chile, former chairman of the International Astronomical Union)
  • Dr. Arne Henden (former staff member of the U.S. Naval Observatory, now director of the AAVSO)
  • Prof. Dr. Jan-Willem Pel (Kapteyn Institute Groningen)
  • Prof. Dr. Frank Verbunt (University of Utrecht).

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We recommend for your stay the University Guesthouse, Kleine Kromme Elleboog 7-b, 9712 BS Groningen, tel: +31 50 3113424, fax: +31 50 363 4100,
university guesthouse

Single Room: 58 Euros
Double Room: 75 Euros
Apartment (for 2 persons) with kitchen en suite: 85 Euros
Breakfast per person: 9 Euros
All rooms are equipped with a shower and a toilet in the room.
All prices are per night including all taxes.

Book your room at the University Guesthouse using this  online
reservation form.
Enter in the field "Participates in congres" the following text: jurriens variable stars 50

If you come alone and would like to share a room with another participant, please contact the organisation. We will pair you with another participant who would like to share a room.

There are many other hotels in Groningen. We recommend the following hotels:
In the centre:
Martini Hotel Groningen - www.martinihotel.nl - +31 50 3129919
Hotel de Doelen -
www.hotel-dedoelen.nl - +31 50 3127041
NH Hotel de Ville -
www.nh-hotels.com - +31 50 3181222
Schimmelpenninckhuys -
www.schimmelpenninckhuys.nl - +31 50 3189502
Hotel Corps de Garde -
www.corpsdegarde.nl - +31 50 3145437

Outside the centre:
Hampshire Hotel Groningen - www.hampshirehotels-groningen.nl - +31 50 3162955
Mercure Hotel Groningen Martiniplaza -
www.accorhotels.com - +31 50 5258400
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The location

Groningen is the capitol of the province with the same name. It is one of the oldest cities in the Netherlands. The name Groningen appears for the first time in the records in 1040, but from archaeological excavations it is clear that the city must be much older. In the Middle Ages Groningen has its glory period and it changes into a city-state.
  1. Train station
  2. Universiteitsmuseum
  3. University guesthouse

Route description to the University Guesthouse
Coming from the Central Station
Leaving the Station from the main entrance, walk straight through the arch in front of the Groningen
Cross the bridge and walk straight ahead into the center of the city.
On your way, you will cross a very busy street, please be careful.
After about 5-10 minutes, you will cross the Vismarkt (Fish market).
Keep going straigt ahead into the Stoeldraaierstraat.
After 50 metres, the name of the street changes into Oude Kijk in 't Jatstraat.
On your right you will find Bookstore "Boomker & Savenije", go left into the small alley, called the
Kleine Kromme Elleboog.
On your right is the Guesthouse. Please ring the bell for reception.
This walking route will take approximately 10-15 minutes.

The famous Martini Tower is erected in those days. Groningen joins the newly founded Republic of the Netherlands at the end of the sixteenth century. The university is founded in 1614. Although Groningen is severely damaged during the Second World War, many historic building have survived the war. It is very nice to do a city walk through the centre. Besides historic buildings, Groningen offers many restaurants, café's, museums and theatres. Both the University Guesthouse and the Univeriteitsmuseum are in the middle of the centre of Groningen, so after the program it is very nice to spend some time there.
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The climate

October is a typical autumn month. It can be a nice Indian summer with maximum temperatures of 20°C (68°F), or grey with lots of rain and maximum temperatures of 10°C (50°F). It is therefore advisable to keep an eye on the weather forecast and to bring suitable clothes accordingly.
The average maximum temperature In October is 13°C (55°F) and the average minimum temperature 6°C (43°F).
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Arriving by plane
There are two primary ways to go to Groningen by plane.
  • You can fly to Bremen airport, Germany (airport code BRE). From the airport you can take the Public Express Bus to Groningen. Departure times: 06.30, 13.30, 17.15 and 23.45 o'clock. The trip takes 2 hours and 15 minutes and a return ticket costs 25 Euros.
  • You can also fly to Amsterdam airport (Schiphol), the Netherlands (airport code AMS). From the airport you can take a direct train to Groningen. You can plan your train trip using www.ns.nl/cs/Satellite/travellers. Choose Schiphol as departure station and Groningen as arrival station.
The University Guesthouse is at walking distance from the station.

Arriving by train
From Den Haag (The Hague) and Schiphol airport there are direct trains to Groningen. When you come from another direction you will have to get to Zwolle and change trains there. There are two Intercity trains per hour that go from Zwolle to Groningen. You can plan your train trip using http://www.ns.nl/cs/Satellite/travellers. Choose Groningen as arrival station.
The University Guesthouse is at walking distance from the station.

Arriving by car
From Zwolle you can reach Groningen using the A28. From Heerenveen you can reach Groningen using the A7. From Bremen (Germany) you can reach Groningen using the E22.
You can plan your car trip for instance by using

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Meeting registration

Register online here
The registration fee is 50 Euros. In this fee the reception on Friday afternoon, the lunches on Saturday and Sunday, the diner op Saturday and coffee and tea during the breaks are included.
Participants from a country belonging to the European Union can pay their registration fee by transferring 50 Euros to the Postbank account 489829 (BIC: INGBNL2A , IBAN: NL40 INGB 0000489829) of 'Penningmeester Werkgroep Veranderlijke Sterren', Israelsstraat 5, 9801 EH Zuidhorn mentioning “European Variable Star Meeting”. Participants from a country outside the European Union are requested to contact the organisation to make arrangements for their payments.
The deadline for registration is October 1, 2010. When you would like to apply after this date, please inquire first if this is still possible.

*Already registered:


Eric Broens

Alfons Diepvens

Josch Hambsch

Francois Van Loo

Johan Van De Looy

Bart Staels

Patrick Wills


Veikko Makela

Arto Oksanen


Thorsten Lange

Kirill Sokolovsky


Erwin van Ballegoij

Adriaan Blauw

Victor van den Bosch

Reinder Bouma

Georg Comello

Darryl Everon

R. Jansen

Theo Jurriens

Gauke Kuipers

Jeremio Maduro

Frans Nieuwenhout

Jan-Willem Pel

Frank Verbunt

*North Cyprus*

Ozge Ögmen

Yenal Ögmen

*United Kingdom*

Des Loughney

*United States*

Arne Henden

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Call for presentations

You are invited to do a presentation on variable stars or related topics. The presentations will be kept on Saturday October 23 and Sunday October 24, 2010. If you would like to do a presentation, please submit the title and the abstract no later than October 1, 2010.
It is also possible to do a poster presentation during the breaks. If you would like to do a poster presentation, please submit the title of your poster no later than October 1, 2010.

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On Friday October 22 the program will be at the Kapteyn Institute, Landleven 12 (Zernike building), Groningen. On Saturday October 23 and Sunday October 24 the program will continue in the Universiteitsmuseum (museum of the university), Oude Kijk in ‘t Jatstraat 7a, Groningen.


*Friday October 22*

  • 14.30: Registration at Kapteyn Institute

  • 15.30: A Photometric Survey of the Sky (Arne Henden)
        • The positions of stars are well-known, with many ground-based and satellite surveys covering the entire sky.  The brightness of stars, and their colour or temperature, is a different story.  There is no existing photometric catalogue of the entire sky going fainter than what you can see with a pair of binoculars. An enormous amount of large telescope time is spent every year to measure the brightness of stars for scientific projects. The AAVSO is currently conducting an all-sky survey in five wavelength bands to finally solve this problem. The talk will give details of what kind of telescopes, cameras and software are needed, how you perform such a survey, and potential uses of the final database.

  • 16.30: Reception, followed by a visit to Blaauw Observatory

*Saturday October 23*

  • 10.00: Registration at the University Museum

  • 10.30: Welcome (Theo Jurriens)

  • 10.45: How it began (Georg Comello)
        • In June 1959 I started observing variable stars using a 42 mm refractor. This hap­pened in close correspondence with a Belgian society: Société´ Belge d'Astronomie. So the seed of the Werkgroep Veranderlijke Sterren der KNVWS (the Variable Stars Section of the Royal Dutch Society of Meteorology and Astronomy) lies in Belgium. In March 1960 I started my job for Dr. Lucas Plaut at the Kapteyn Laboratory (Nowa­days it is called Kapteyn Institute). I had to estimate the brightness of mainly RR Lyrae stars on the photographic plates of the Palomar-Groningen Survey. Dr. Plaut was very interested in my amateur observations on variable stars and he was sur­prised about the fact that I did those in close collaboration with a Belgian organization. He took the initiative to start a variable star section within the NVWS. The section was founded in the library of the Utrecht Observatory on the 23^rd of October 1960. Since that date the Variable Stars Section is actively promoting the observation of variable stars. In this talk a short report is given on the history of the Section. Further an overview is given of the problems we had to obtain good charts and useful sequen­ces. This was not easy at the beginning.

  • 11.15: Half a century of variable star research (Jan Willem Pel)
        • Like in every other field in astronomy, the scope of variable star research has changed dramatically over the past 50 years. During these decades - thanks to the developments in space research and radioastronomy - nearly the entire electromagnetic spectrum has become accessible for astronomical observations. This led to the discovery of fascinating new classes of variable objects such as pulsars and X-ray binaries. The body of observational data on variable stars that we have today is not only very much bigger, but also much more diverse than what we had around 1960. At the same time there has been tremendous progress in our theoretical understanding of stellar physics. Starting in the late 1950's the theories of stellar structure, evolution and pulsation developed rapidly. For the first time it became possible to make detailed comparisons between theory and observations of stars. Variable stars turned out to be invaluable as test objects for astrophysical theory. At the same time they play a crucial role as 'standard candles' for the cosmic distance scale. This talk will summarize some highlights from the past half century.

  • 12.00: The Work and Life of Lukas Plaut (Adriaan Blaauw)
        • abstract missing

  • 12.30: Contributions of the WVS to the AAVSO (Arne Henden)
        • There have been decades of collaborative observing between the WVS and the AAVSO, plus many prior years of European contributions to our observational database. I will highlight some of the important observers, where your observations have been critical for projects, and make predictions for the future.

  • 13.00: Lunch

  • 14.00: YY Boo and TT Ari, very interesting variable stars (Josch Hambsch)
        • YY Boo, an Algol like eclipsing binary star, has been found to show also pulsations with high amplitude of 0.1 mag. In a multi-site and multi-month observing campaign in 2010 the complete light curve of this star has been measured in B and V photometric filters. TT Ari is one of the most mysterious cataclysmic variables which has been extensively observed during the last decline in brightness in October 2009, which was the first since the 1980ties. During several months the star was observed showing sometimes variations during one night from 13.5 to 16.5 mag. Results about both stars during their respective campaign will be shown and discussed.

  • 14.30: The Deeply Eclipsing Polar "OT_J0711+44" (Arto Oksanen)
        • Summary of observations of the newly discovered deeply eclipsing polar CSS 081231:071126+440405 made by Arto Oksanen at the Hankasalmi observatory in Finland. Several light curves covering 22 nights, 52 eclipses and over 5200 data points will be presented. Preliminary results of the analysis will be discussed.

  • 15.00: Using an amateur robotic telescope for observing variable stars (Frans Nieuwenhout)
        • Since 2005 a telescope has been established in the North of Holland which can be operated from a distance via internet. It has turned out to be a suitable instrument for doing variable star observations. The presentation will show with some examples how this is being done. It can be useful tool to gain some first experience by those people considering to start observing with a CCD camera.

  • 15.15: Break and Group Picture

  • 15.45: A Search for Dwarf Novae (Patrick Wils)
        • Cross-matching blue objects from the Sloan Digital Sky Survey and the Galaxy Evolution Explorer with the astrometric catalogues USNO-B1.0, GSC2.3 and CMC14, and those with large magnitude differences, revealed some 70 dwarf novae candidates.  Several of those have been confirmed spectroscopically or have recently been observed in outburst.  Data from the Catalina Real-time Transient Survey indicate that the recently discovered dwarf novae have less frequent outbursts compared to those known before. This suggests that a large number of dwarf novae are still unknown.

  • 16.15: Supernovae (Frank Verbunt)
        • abstract missing

  • 17.00: The Future of Amateur Variable-Star Observing (Arne Henden)
        • PanSTARRs is beginning its survey of the sky.  ASAS is now covering both northern and southern hemispheres.  LSST is just around the corner.  Do these and other surveys leave room for the amateur to contribute?  I'll discuss this important topic, plus give some ideas of future projects and instrumentation where amateurs will be major players for a long time to come. The Future of Amateur Variable-Star Observing  (This talk will be followed by a discussion).

  • 19.00: Reception followed by dinner

*Sunday October 24*

  • 10.00: Registration at the University Museum

  • 10.30: *Period Changes in SY Herculis* (Erwin van Ballegoij)
        • Although the well known Mira variable SY Herculis is extensively studied since the 1960ties, it is still not possible to predict the time of maximum with sufficient accuracy. A first study by Ahnert (1976) showed that the period of SY Her is not constant, but changes from time to time. In this follow-up study the period evolution of SY Her is followed from 1967 until 2010 using AAVSO data.

  • 11.00: *The challenge of observing transits of exoplanets* (Frans Nieuwenhout)
        • An exoplanet transit causes a dip in stellar intensity of at most a few tens of milli-magnitude. To measure these requires careful attention to reduce all possible sources of error to to a sufficiently low level. Some difficulties will be discussed and ways to overcome them will be shown. A few examples of transits will be given.

  • 11.30: *Time Series CCD Photometry from Nyrölä and Hankasalmi observatories* (Arto Oksanen)
        • The two country-side observatories of Astronomical association Jyväskylän Sirius will be described. The both observatories have 40 cm telescopes that have been optimized for time-series CCD photometry, but the observing is very different between a "manual" observatory versus a fully automated one. The most important photometric observations made at the observatories will be presented.

  • 12.00: *Variable Stars from the Chandra Guide Camera* (Arne Henden)
        • The Aspect Camera, the main guide camera for the Chandra X-Ray Satellite, monitors 4-6 stars continuously for hours to days in order to control the positioning of the satellite.  The photometric observations are downloaded to the ground, and checked to ensure proper star acquisition and guiding.  The generated light curves have also been examined for stellar variability, and nearly a thousand stars have been found to be variable.  These are all in the 8-10mag range, easy to observe with small telescopes, yet are almost all new variables.  The majority are low-amplitude stars, ideal for CCD or DSLR observing, but there are some higher amplitude eclipsing systems and long-period variables that can be followed visually. This talk will present some of the stars, give the website where you can examine the light curves, and suggest a campaign to monitor as many of these stars as possible.

  • 12.30: Departure to Franeker with Lunchbox

*Poster presentations

  • Discovery of the Eclipsing Binary VSX J194712.7+361748*** (Yenal Ögmen)

  • 50 Years of Variable Star Observing in the Netherlands* (Erwin van Ballegoij)

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Further information

If you have any questions on the European Variable Star meeting, don't hestitate to contact the organizers.
For further information about the city and the province of Groningen we recommend the following website: toerisme.groningen.nl/english

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