Berdnikov, L. N.L. N.BerdnikovKniazev, A. Yu.A. Yu.KniazevDambis, A. K.A. K.DambisKravtsov, V. V.V. V.KravtsovPastukhova, E. N.E. N.Pastukhova2026-10-192026-10-192017-07Berdnikov, L. N.; Kniazev, A. Yu.; Dambis, A. K.; Kravtsov, V. V.; Pastukhova, E. N. (2017-07). Variability of the Period of the Star DU Monocerotis, an RR Lyrae Variable with the Blazhko Effect. ASTRONOMY LETTERS-A JOURNAL OF ASTRONOMY AND SPACE ASTROPHYSICS, 43 (7), 489-500. https://doi.org/10.1134/s10637737170700151063-77371562-6873https://hdl.handle.net/20.500.12740/25189In 2012-2014 we obtained 3641 CCD frames of the fields of the RR Lyrae (AB subtype, P = 0.583 days) variable DU Mon with BV I-c filters using the 76-cm telescope of the South African Astronomical Observatory (SAAO) and the 1-m telescopes of the Las Cumbres Observatory Global Telescope Network (LCOGT). Our observations confirmed the presence of the Blazhko effect that we suspected previously and allowed its period to be determined, P-Bl - 60.(d)52 +/- 0.(d)03. Using all of the available observations, we constructed an O-C diagram spanning a time interval of 86 years that revealed at least one abrupt change in the pulsation period (a decrease by 15.26 s).enpulsating variable starsRR Lyrae starsBlazhko effectpulsation period variabilityArticulohttps://doi.org/10.1134/s1063773717070015