This image of Neowise from July 14, 2020 used the 12.5″ f/9 RC in my home observatory, tracked by the Paramount ME, with a Canon 6D Mark II.  The image is a composite of 12 subframes, each 10 sec, unguided, with no darks or flats, manually aligned in Photoshop, combined in PixInsight, then stretched with additional tweaking in Photoshop. (Manual alignment was performed since neither PixInsight or Registar would align the data.)  A central dark lane is easily visible, possibly representing a shadow caused by the nucleus?  Alas, the ion tail is conspicuously absent, a product of the slow f ratio, short exposure, and the long focal length. (One gets the slight hint of a dim bluish structure starting to take shape on the right side of the comet?)