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We present an analysis of three Chandra High Energy Transmission Gratingsobservations of the black hole binary Cyg X-1/HDE 226868 at different orbitalphases. The stellar wind that is powering the accretion in this system ischaracterized by temperature and density inhomogeneities including structures,or "clumps", of colder, more dense material embedded in the photoionized gas.As these clumps pass our line of sight, absorption dips appear in the lightcurve. We characterize the properties of the clumps through spectral changesduring various dip stages. Comparing the silicon and sulfur absorption lineregions (1.6-2.7 keV $\equiv$ 7.7-4.6 {\AA}) in four levels of varying columndepth reveals the presence of lower ionization stages, i.e., colder or densermaterial, in the deeper dip phases. The Doppler velocities of the lines areroughly consistent within each observation, varying with the respective orbitalphase. This is consistent with the picture of a structure that consists ofdifferently ionized material, in which shells of material facing the black holeshield the inner and back shells from the ionizing radiation. The variation ofthe Doppler velocities compared to a toy model of the stellar wind, however,does not allow us to pin down an exact location of the clump region in thesystem. This result, as well as the asymmetric shape of the observed lines,point at a picture of a complex wind structure.

Chandra X-ray spectroscopy of the focused wind in the Cygnus X-1 system III. Dipping in the low/hard state