Orestis,
I like your observation notes; you really try to describe accurately what you are seeing.
I think that your observation of "arms" or possible spiral arms in NGC 5248 is very plausible;
The bright portion of N5248 is smallish, about 3 arcminutes across, but the two principal spiral arms look narrow and well defined in photographs.
Here is an image of N5248 from Zsolt Frei's galaxy atlas:
Here is an amateur LRGB of reasonably good quality:
NGC 5248 has an intense region of current or recent star formation near its very centre, which is seen in photos to be a ring of giant star-forming patches that are luminous with the light of numerous OB stars ( = young blue supergiants).
The ring closely surrounds the very centre of this galaxy.
This ring would probably manifest in the telescope as a tiny very bright core, as you have observed in your log.
cheers,
the bad galaxy man