Light pollution and apparent magnitude of objects in solar system Dust along the ecliptic scatters light, causing “light pollution” throughout the orbital plane of the solar system. If an object like, say, the sun's corona, had its brightness measured from above the ecliptic, would the measurement reflect that?
The answer is yes: dust is highly constrained to the ecliptic plane and so viewing from above the plane would result in less light that needs to be subtracted from observations of the solar corona.  The zodiacal light is quite strong in the direction of the sun because the dust strongly scatters in the forward direction. Near the Sun, its surface brightness is somewhere around 21 - 23 mag/arcsec$^2$ from our viewpoint in the ecliptic, and this would be an additive contamination to any measurement of the Sun's corona.  From the ecliptic pole, this light foreground would be much less.  Of course, a careful observer would know to also measure the zodiacal light contribution and to subtract it off, so both observers would get the same brightness for the corona roughly.  The observer at the pole would have lower noise for a comparable instrument and observing time.