Of the three Messier clusters in Auriga, M38 is the most difficult to see in small instruments under heavy light pollution.
Under dark skies, it appears as a gentle diffuse cloud in binoculars and in small telescopes at very low powers, but the average
brightness of this cloud is fairly low, so it stands out poorly against bright skies. Therefore, the cluster is usually
visible in the city only if the individual stars can be resolved.
My 70mm refractor shows a fair number of M38's stars in the city, but not quite enough to make it obvious that this is
a true cluster rather than a random alignment of stars. Just enough extra stars are visible under suburban skies to
make the cluster completely convincing.
The 178mm scope shows far more stars in the city than the 70mm scope shows in the suburbs, yielding a much more impressive
view. M38 is improved both by darker skies and by larger apertures, but of the two, aperture is much more important.
This is typical of objects with high surface brightness, and particularly true for stars and star clusters.