But none of those techniques is applicable to variations in the CMB (the subject of this article), which is a more or less uniform glow at constant (and in some

But none of those techniques is applicable to variations in the CMB (the subject of this article), which is a more or less uniform glow at constant (and in some sense, maximal) redshift (and by definition, behind the "background" stars). I suppose that if this "axis of evil" were due to a pattern in nearby dust clouds we might be able to see some hints of paralax, but paralax would probably be difficult to measure for something as diffuse and broad as the pattern visible in this data. It's my impression, for the record, that cosmologists are pretty confident that these variations aren't due to intervening dust. My sense is that the spectrum of the CMB in any given direction is very clearly a blackbody spectrum (the most precise blackbody spectrum in nature, in fact), so any absorption due to foreground matter should be pretty recognizable (and possibly even something they could correct for).