Optical spectrophotometric monitoring of comet C/2006 W3 (Christensen) before perihelion P. P. Korsun, I. Kulyk, O. V. Ivanova, O. V. Zakhozhay, V. L. Afanasiev, A. V. Sergeev and S. F. Velichko A&A, 596 (2016) A48 Published online: 28 November 2016 DOI: 10.1051/0004-6361/201629046