Here’s an extract from the NASA website www.NASA.gov.
“Working with astronomical image processors at the Space Telescope Science Institute in Baltimore, Md., renowned astro-photographer Robert Gendler has taken science data from the Hubble Space Telescope (HST) archive and combined it with his own ground-based observations to assemble a photo illustration of the magnificent spiral galaxy M106.
Gendler retrieved archival Hubble images of M106 to assemble a mosaic of the center of the galaxy. He then used his own and fellow astro-photographer Jay GaBany’s observations of M106 to combine with the Hubble data in areas where there was less coverage, and finally, to fill in the holes and gaps where no Hubble data existed.
The center of the galaxy is composed almost entirely of HST data taken by the Advanced Camera for Surveys, Wide Field Camera 3, and Wide Field Planetary Camera 2 detectors. The outer spiral arms are predominantly HST data colorized with ground-based data taken by Gendler’s and GaBany’s 12.5-inch and 20-inch telescopes, located at very dark remote sites in New Mexico. The image also reveals the optical component of the “anomalous arms” of M106, seen here as red, glowing hydrogen emission..”