M 94 was discovered by Pierre Mechain in 1781 and catalogued by Charles Messier two days later.  It is about 16 million light years away in Canes Venatici.  It has an inner ring about 5400 light years in diameter and an outer ring about 45000 light years in diameter.  The inner ring is the site of strong star formation.  The outer ring is a complex structure of spiral arms when viewed in mid-IR and UV.  The outer ring is active; it contains approx. 23% of the galaxy's total stellar mass and contributes about 10% of the total new stars.

Imaging sessions were difficult as most nights data collected were either windy or poor seeing conditions.  Star shapes were generally elongated or soft (softer than SCTs usually deliver) due to weather conditions, so lots of effort was devoted to fixing the stars to be something better than "not good."  As many have discovered, processing this galaxy is challenging due to the high dynamic range between the brighter core and the extended faint outer structure.

Histogram Transformation (HT) vs Generalised Hyperbolic Stretch (GHS):  see Revision B

Referencing PixInsight's HT process and GHS script:  I was not an early adopter of GHS even after the initial round of tutorials were released.  It seemed clumsy and non-intuitive at first glance; however, after finally devoting some time to the script it started to make sense.  I had already worked hard on this M 94 image and decided to give GHS a chance.  It made a big difference in the detail obtained in the galaxy's core during Lum stretch as HT left a bright non-descript core no matter how I manually stretched it.  See the Revision for a side-by-side comparison of the initial stretch to similar "brightness" levels - no other processing was done and no attempt was made to gain better detail after HT using other processes.  GHS worked very well for this image and I look forward to its future enhancements.

Imaged over several nights:  Mar 16, 21, 25 and 28; Apr 10, 2022.