This is yet another attempt at improving my image of M101, the Pinwheel Galaxy in Ursa Major. This version does have more detail than the last, although there is not much gain in the brightness of the image.
The Pinwheel Galaxy (also known as NGC 5457) is a face-on spiral galaxy distanced 21 million light-years away from Earth in the constellation Ursa Major. First discovered by Pierre Méchain on March 27, 1781, it was communicated to Charles Messier who verified its position for inclusion in the Messier Catalogue as one of its final entries.
Canon 60D with an Astronomik CLS filter, at the prime focus of the KPO 18″ Reflector. 34 frames of 120 seconds for a total integration time of 68 minutes. All frames captured at ISO 1600. Subframes captured and stacked in Nebulosity, processed in StarTools, and finished in Aperture.
Click on the image for a larger version.