  The historical Hungarian auroral record extends from 1523 to 1960 and is
longer than the sunspot record. Harmonic analysis reveals four major
multidecadal secular cycles forming an approximate harmonic set at periods of
42.85, 57.13, 85.7 and 171.4 years. These four frequencies are very close to
the four major heliospheric oscillations relative to the center of mass of the
solar system caused by Jupiter, Saturn, Uranus and Neptune. Similar frequencies
are found in solar radiation models based on long cosmogenic isotope records
(Steinhilber et al. 2012) and in long records of naked-eye sunspot observations
(Vaquero et al., 2002). Harmonic regression models are used to reconstruct and
forecast aurora and solar activity for the period 1956-2050. The model
predicts: (1) the multidecadal solar minimum in the 1970s that is also observed
in the sunspot record; (2) a solar maximum in 2000-2002 that is observed in the
ACRIM total solar irradiance satellite composite; (3) a prolonged solar minimum
centered in the 2030s. These findings support a hypothesis that the Sun, the
heliosphere and the terrestrial magnetosphere are partially modulated by
planetary gravitational and magnetic forces synchronized to planetary
oscillations, as also found in other recent publications (Scafetta, 2010,
2012a, 2012c, 2012d; Abreu et al., 2012; Tan & Cheng, 2012).
