About Project

Project name: Binary Systems of South and North (BSN-Project)

Selecting binary systems:
  1. Eclipsing Binary-Star Systems.
  2. Range greater than 0.1 magnitudes (easier for inexperienced observers to record useful data)
  3. Period less than 0.4 day (so full the light curve can be recorded in a few nights) for contact systems
  4. Brighter than V magnitude 15 at minimum.
  5. Observing in more than 2 filters. Especially V and B bands.
  6. Select systems whose light curves have not yet been studied or have been studied in the far years ago.
Project aims:
  1. Times of Minimum to refine period (VSS already has a project on southern eclipsing binaries with this aim, results published annually).
  2. Full light curves in one or more filters for light curve modelling.
  3. O-C diagram to look for apsidal motion, period change, third bodies, etc. (this would require repeated observations over many years).
  4. Understudied or newly discovered eclipsing binaries (surveys such as ASAS, ASAS-SN, SWASP, etc. have discovered many EB’s that should be observed to confirm the type, period, etc.).
  5. Publishing results in the form of papers.

The project founders

  • Atila Poro
  • Mark G. Blackford
  • Edwin Budding

Project Team

  • Atila Poro (Astronomy Department of the Raderon AI Lab., Canada)
  • Mark G. Blackford (Variable Stars South, Congarinni Observatory, Australia)
  • Edwin Budding (Carter Observatory, New Zealand)
  • Fahri Alicavus (Çanakkale Onsekiz Mart University, Türkiye)
  • Raul Michel Murillo (Observatorio Astronomico Nacional, UNAM, Mexico)
  • Mehmet Tanriver (Erciyes University, Türkiye)
  • Eduardo Fernandez Lajus (Universidad Nacional de La Plata, Argentina)
  • Filip Walter (Variable Star and Exoplanet Section of Czech Astronomical Society, Czech Republic)
  • Sabrina Baudart (Société Astronomique de France, France)
  • Laurent Corp (Garden Observatory and Société Astronomique de France, France)
  • Ehsan Paki (Tehran, Iran)
  • Ahmet BULUT (Çanakkale Onsekiz Mart University, Türkiye)
  • Ahmet KESKİN (Erciyes University, Türkiye)
  • Alessandro Marchini (University of Siena, Italy)
  • Jean François coliac (OABAC Binaries Observatory and Société Astronomique de France, France)
  • František Lomoz (Variable Star and Exoplanet Section of Czech Astronomical Society, Czech Republic)
  • Yasemin Aladağ (University of Çukurova, Türkiye)
  • Kai LI (Shandong University, China)


  • Poro, A., Alicavus, F., Fernández-Lajús, E., Davoudi, F., MirshafieKhozani, P., Blackford, M.G., Budding, E., Jalalabadi, B.Z., Rahimi, J. and Farahani, F.A., 2020. BVRI Photometric Observations, Light Curve Solutions and Orbital Period Analysis of BF Pav. Research in Astronomy and Astrophysics, Vol. 21 No. 8. DOI: 10.1088/1674-4527/21/8/203
  • Poro, A., Blackford, M.G., Davoudi, F., Mohandes, A., Madani, M., Rezaei, S. and Bozorgzadeh, E., 2021. The New Ephemeris and Light Curve Analysis of V870 Ara by the Ground-Based and TESS Data. Open Astronomy, 30(1), pp.37-44. DOI: 10.1515/astro-2021-0004
  • Rahimi, J., Lashgari, E., Ghanbarzadehchaleshtori, M., Boudesh, A., Davoudi, F., Farahani, A., Walter, F., Hladík, B., Nosal, P. and Poro, A., 2021. The first light curve solutions and period study of two contact binary systems: V1370 Tau and QQ Boo. New Astronomy, 84, p.101499. DOI: 10.1016/j.newast.2020.101499
  • Poro, A., Davoudi, F., Alicavus, F., Khakpash, S., Esmer, E.M., Basturk, O., Lashgari, E., Rahimi, J., Aladag, Y., Aksaker, N. and Boudesh, A., 2021. The first light curve solutions and Period study of BQ Ari. Astronomy Letters, 47(6), pp.402-410. DOI: 10.1134/S1063773721060050
  • Poro, A., Zamanpour, S., Hashemi, M., Aladağ, Y., Aksaker, N., Rezaei, S. and Solmaz, A., 2021. BO Ari Light Curve Analysis using Ground-Based and TESS Data. New Astronomy, 86, p.101571. DOI: 10.1016/j.newast.2021.101571
  • Poro, A., Blackford, M.G., Salehian, S.R., Jahangiri, E., Dastjerdi, M.S., Gozarandi, M., Karimi, R., Madayen, T., Bakhshi, E. and Hedayati, F., 2022. The First Photometric Study of AH Mic Contact Binary System. Research in Astronomy and Astrophysics. DOI: 10.1088/1674-4527/ac6417
  • A. Poro, E. Paki, M. G. Blackford, F. Davoudi, Y. Aladag, S. Zamanpour, S. Sarabi, A. Halavati, N. Aksaker, H. Bagis, J. Rahimi, H. Guilani, A. Akyuz, F. Jahediparizi, O. Doner, Z. Ashrafzadeh, 2022. The Photometric Study of Six W UMa Systems and Investigation of the Mass–Radius Relations for Contact Binary Stars. Publications of the Astronomical Society of the Pacific. DOI: 10.1088/1538-3873/ac71cd
  • TANRIVER, M., Poro, A., BULUT, A., KESKiN, A. and Blackford, M.G., 2023. The First Multiband Photometric Light Curve Solutions of the V Gru Binary System from the Southern Hemisphere. Research in Astronomy and Astrophysics. DOI: 10.1088/1674-4527/acc506
  • Paki, E., Baudart, S. and Poro, A., 2024. The First Photometric Study of the Binary System CSS J003106. 8+ 313347. Astrophysics, pp.1-11. DOI: 10.48550/ARXIV.2307.15132
  • Poro, A., Fernandez Lajus, E., Madani, M., Sabbaghian, G., Nasrollahzadeh, F. and Jahediparizi, F., 2023. Light Curve Analysis of the AP Dor Binary System using Ground-Based and TESS Observations. Research in Astronomy and Astrophysics. DOI: 10.1088/1674-4527/ace027
  • Poro, A., Paki, E., Alizadehsabegh, A., Khodadadilori, M., Salehian, S.R., Hedayatjoo, M., Hashemi, F., Dashti, Y. and Mohammadizadeh, F., 2023. Two-dimensional Parameter Relationships for W UMa-type Systems Revisited. Research in Astronomy and Astrophysics, 24(1), p.015002. DOI: 10.1088/1674-4527/ad0866
  • Soomandar, S. and Poro, A., 2024. A new look at the YY CrB binary system. New Astronomy, 105, p.102112. DOI: 10.1016/j.newast.2023.102112
  • Poro, A., Tanriver, M., Michel, R. and Paki, E., 2024. Global Parameters of Eight W UMa-type Binary Systems. Publications of the Astronomical Society of the Pacific (PASP). arXiv preprint arXiv:2401.09903.
  • Poro, A., Hedayatjoo, M., Nastaran, M., Nourmohammad, M., Azarara, H., AlipourSoudmand, S., AzarinBarzandig, F., Aliakbari, R., Nasirian, S. and Poor, N.K., 2024. Estimating the absolute parameters of W UMa-type binary stars using Gaia DR3 parallax. New Astronomy, p.102227. DOI: 10.1016/j.newast.2024.102227
  • A. Poro, S. Baudart, M. Nourmohammad, Z. Sabaghpour Arani, F. Farhadi, S. Ranjbar Salehian, A. Sarostad, S. Ranjbaryan Iri Olya, M. Hadizadeh, A. Khodaei, 2024. First Light Curve Analysis of NSVS 8294044, V1023 Her, and V1397 Her Contact Binary Systems. Research in Astronomy and Astrophysics. DOI: 10.1088/1674-4527/ad3a2c
  • Alizadehsabegh, A., Lomoz, F., Poro, A. and Narimani, A., 2024. First Light Curve Study of the Low Mass Contact Binary V0610 Vir. Astrophysics Journal. arXiv preprint arXiv:2309.14369.
  • Poro, A., Tanriver, M., Sarvari, E., Zavvarei, S., Azarara, H., Corp, L., Baudart, S., Ababafi, A., Kahali Poor, N., Zare, F. and Bulut, A., 2024. BSN: Photometric Light Curve Analysis of Two Contact Binary Systems LS Del and V997 Cyg. Research in Astronomy and Astrophysics. DOI: 10.1088/1674-4527/ad30b2

BSN Meetings

  • The first meeting was held in November 2023 in Paris, France. This meeting was hosted by the French Astronomical Society and was held with a significant number of participants and speakers. A total of 21 scientific lectures were given in this meeting during two days. Link for more information: EBS International Meeting
  • The second international meeting of the BSN project will be held at Shandong University in Weihai, China, at the end of September 2024. For more information, please visit the meeting's page


Atila Poro: