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Hα observations of solar large-scale fields were used to reconstruct the heliosphere structure for the time interval of 1915–1996. A special method of polar correction was developed. The expansion coefficients in Legendre polynomials were calculated. An atlas of the heliosphere structure was compiled. ‘Inferred’ strength of the polar and equatorial field in 1915–1996 years was calculated. Cyclic variations of the polar field and the number of polar plages were compared to show a satisfactory agreement. The q parameter, characterizing the divergence of the polar plumes in the epochs of the solar minimum, was calculated and its quasi-periodic behaviour with a period of the order of 70 years was revealed. Our calculations were tentatively compared with the interplanetary magnetic field structure.