• Surname: Jetsu
• Forenames: Lauri, Johannes
• Title: University lecturer in astronomy
• Education: MSc (1988, Univ. Helsinki), PhD (1994 Univ. Helsinki), Docent (1996, Univ. Helsinki), Docent (1997, Univ. Oulu)
• Main research interest: Period analysis of astronomical, geophysical and egyptological data (i.e. unequally spaced time series or series of time points)
• Address: Department of Physics, P.O.Box 64 (Gustaf Hällströmin katu 2a), FIN-00014 University of Helsinki, FINLAND
• Phone: +358-2941 22946 (work) and +358-45-674 6983 (home), Email: lauri.jetsu@helsinki.fi

My best guess

Current research

"Discrete Chi-Square Method can model and forecast complex time series, like El Nino data between 1870 and 2024"

The short Note added to the Proof (Page 31) is now in the end of our paper. We had no yearly mean for the year 2025. Our original analysis for the years 1870-2024 now confirms that our year 2025 forecast succeeds.

Algol research

Our research of the role of the eclipsing binary Algol in Ancient Egypt was published in these two papers

"Did the ancient Egyptians record the period of Algol - The Raging one?"

2013, The Astrophysical Journal, 773 , A1 (1-14) (2013, July 18th)

"Shifting Milestones of Natural Sciences: The Ancient Egyptian Discovery of Algol's Period Confirmed"

2015, PLOS ONE, 10(12), e0144140 (23pp) (2015, December 17th)

Here is some of the public response

to these publications.

• Lectures: Tieteellinen laskenta I (Scientific computing I)
• Lectures: Tähtitieteen käytännön menetelmät (Practical methods in astronomy)
• Lectures: Havaitsevan tähtitieteen peruskurssi I (Observ Observational astronomy I)
• Lectures: Aikasarja-analyysi tähtitieteessä I (Time series analysis in astronomy I)
• Lectures: Aikasarja-analyysi tähtitieteessä II (Time series analysis in astronomy II)
• Lectures: Muuttuvat tähdet (Variable stars)
• Lectures: Binary Stars (Binary Stars)
• PhD thesis supervision: L. Alha, T. Hackman, J. Lehtinen, S. Porceddu
• M.Sc. thesis supervision: M. Kokko, S. Porceddu, T. Lyytinen, J. Lehtinen, V. Solea, V. Mäkelä, I. Hiilesmaa
• Databases: | Physics: e-print Archive | ADS | Simbad | Web of Science |
• Observatory parties on: | June 8th, 2001 | April 26th, 2002 | July 25th, 2003 | April 2nd, 2004 | July, 2004 | October 22nd, 2004 | April 29th, 2005 | August 19th, 2005 | March 31st, 2006 | July 21st, 2006 | July 20th, 2007 | July 25th, 2008 | July 31st, 2009 |

---

Last updated: July 4th, 1642 (AD)