Nancy Chumachenco attended the Curtis Institute of Music in Philadelphia, studying cello with Orlando Cole and Leonard Rose. In the summer of 1961 she spent 7 weeks as a student at the Tanglewood Festival, and during the summer of 1962, she studied with Leonard Rose for 8 weeks at the Meadowmount School of Music.

In 1967 Nancy Chumachenco became a member of the Zurich Chamber Orchestra. In order to raise her children, however, she left the orchestra as a permanent member, but continued to free lance in the chamber orchestra and later for 17 years in the Tonhalle Orchestra, Zurich.

Nancy Chumachenco taught cello for many years. She realised the great challenges and rewards of teaching and working with highly-gifted young musicians, and this became her passion. Her former student Christian Poltéra, who began his studies with her in Zurich, is today one of the most prominent cellists on the international scene. Her young trio with Linus Roth, Violin, Christian Poltéra, Cello and Philippe Jordan, Piano won the top prize for chamber music at the Swiss National Competition in 1992. Other students and ensembles which she taught and coached were equally successful at home and abroad. These activities culminated in the founding of Astona International in 1988. 

Kristoffer Dolatko has taught at Astona International since 2008. In 2011 he was appointed assistant director.

Click here for more about Kristoffer Dolatko

Christoph Balmer was born (1953) and grew up in Zug. He began to play the cello at the age of 9 and ever since then, he has always played in orchestras, sometimes as leader of the section. He is member of the Zug Symphony Orchestra, an excellent amateur orchestra, 1996 - 2020 under the baton of Astona-conductor Jonathan Brett Harrison. Balmer was as the co-founder 1995 - 2020 president of the Zug Cultural Society, the organisation which oversees all cultural institutions and artists in Zug. For over 20 years he was a member of the Music School Commission of the City of Zug. 

As a professional bookshop and book wholesale distributor, Christoph Balmer was the head of the family business into which he was born for over 30 years. Today he is co-owner and president of the board of Bücher Balmer Inc., comprised of two branches in Zug and Steinhausen. Through his extensive professional and voluntary activities, Christoph Balmer is strongly involved in the cultural, political and business world in the region of Zug, which is of benefit to Astona. In the Verein Astona he is responsible for logistics, the finances, the sponsorship, the publicity and concert organisation.

Raphaël Vergères was a member of Astona International from 2001 to 2009 as Coordinator and House Father.and came back to Astona in 2017. 

He studied violin at the Conservatory in Neuchâtel with Jan Dobrezelweski and Stefan Muhmenthaler, graduating in 2001.  In 2003 Raphaël began a study of traditional Chinese Medicine (TCM) in Basel, specialising in acupuncture.  In 2009 he opened his own TCM practice. He specialises in painless acupuncture through the use of a special laser. Raphaël's passion for Asian culture manifests in his fondness of the Japanese martial arts.  As a teenager he began training in karate, and in 2004 he fulfilled his dream of opening his own school of martial arts near Basel, where he has been teaching children, teenagers and adults karate and jiu-jitsu ever since. Today he is employed as a TCM therapist and martial arts teacher.  Previously he worked  as a pedagogic assistant, as a group leader in security services, as an orchestra attendant and as an accountant.