Differences in the right ascension (times cosine declination, top) and declination (bottom) as a function of declination for common sources between the Gaia DR2 subset and ICRF catalogs. The right ascension difference is calculated as Δα^* = Δα cos δ. The shown difference is the median of bins by every certain number of sources for the sake of clarity. The bin size was chosen to be 10 for the ICRF1, ICRF3 K-, and X/Ka-band, along with 25 for other catalogs.