Foreground Dust Obscuration
As seen from Earth, the group lies near the plane of the Milky Way (a region sometimes called the Zone of Avoidance). Consequently, the light from many of the galaxies is severely affected by dust obscuration within the Milky Way. This complicates observational studies of the group, as uncertainties in the dust obscuration also affect measurements of the galaxies' luminosities and distances as well as other related quantities.
Moreover, the galaxies within the group have historically been difficult to identify. Many galaxies have only been discovered using late 20th century astronomical instrumentation. For example, while many fainter, more distant galaxies, such as the galaxies in the New General Catalogue, were already identified visually by the end of the nineteenth century, Maffei 1 and Maffei 2 were only discovered in 1968 using infrared photographic images of the region. Furthermore, it is difficult to determine whether some objects near IC 342 or Maffei 1 are galaxies associated with the IC 342/Maffei Group or diffuse foreground objects within the Milky Way that merely look like galaxies. For example, the objects MB 2 and Camelopardalis C were once thought to be dwarf galaxies in the IC 342/Maffei Group but are now known to be objects within the Milky Way.
Read more about this topic: IC 342/Maffei Group
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