Imaged the galaxy NGC 2903 on the nights of April 21, May 5, and May 9, 2023.  My second capture of spring 2023's 'galaxy season.'  NGC 2903 has an apparent magnitude (v) of 9 and an apparent size of 11.5 × 5.25 arcsec.  NGC 2905 is associated with one of this galaxy's spiral arms (see below for explanation).  Also visible the field is another spiral galaxy NGC 2916 that is not associated with NGC 2903.

Per Wikipedia (reference: https://en.wikipedia.org/wiki/NGC_2903):  "NGC 2903 is an isolated barred spiral galaxy in the equatorial constellation of Leo, positioned about 1.5° due south of Lambda Leonis.  It was discovered by German-born astronomer William Herschel, who cataloged it on November 16, 1784. He mistook it as a double nebula, as did subsequent observers, and it wasn't until the nineteenth century that the [url=mw-redirect=https://en.wikipedia.org/wiki/Third_Earl_of_Rosse]Third Earl of Rosse[/url] resolved into a spiral form. J. L. E. Dreyer assigned it the identifiers 2903 and 2905 in his New General Catalogue; NGC 2905 now designates a luminous knot in the northeastern [url=mw-redirect=https://en.wikipedia.org/wiki/Spiral_arm]spiral arm[/url].  This field galaxy is located about 30 million light-years away from the Milky Way, and is a member of the Virgo Supercluster. The morphological classification of this galaxy is SBbc, indicating a barred spiral (SB) with moderate to tightly-wound spiral arms (bc). ...72% of the stellar mass is located in the outer disk of the galaxy, and 20% is found in the bar. The bulge adds 5% of the stellar mass, and its star population is generally older. However, the central =nowrap~650 pc radius volume of the core is a strong starburst region." 

Imaged with a William Optics GT81 at F4.7 (382 mm focal length) using Flat6A II field flattener/0.8x reducer, UVIRcut filter, and ZWO ASI 533MC Pro.  Total integration time of 4 hours: 124 subs at Gain = 100 with an exposure time of 120 sec.

Pre-processed using Pixinsight's weighted batch pre-processing script (WBPP) to perform calibration, debayering, registration, local normalization, and integration.  Background removed using GradXpert.  Post-processing in Pixinsight:  spectrophotometric color calibration, blur x terminator, noise x terminator, masked stretch.  Unscreened stars using StarXTerminator, then further processed the starless image:  generated rangemask and applied for subsequent steps, generalized hyperbolic stretch, curves transformation, and HDR transformation using EasyHDR script, local histogram transformation, color saturation adjustment, and lastly re-screened stars using PixelMath.  Separately processed full image using standard workflow for comparison > result is less detail in the faint regions of the galaxy and better background, but better blend with the background (need to work on my separate starless processing...).  Final image generated as a blend of the two aforementioned images (50% blend using GHS2 image blend mode) for a better overall balanced image.

Rev B:  NGC 2903 OSC RGB image (new process flow using starless processing & re-screened stars, blended with image generated using standard process flow)

Rev C:  NGC 2903 OSC RGB image (new process flow using starless processing & re-screened stars)

Rev D: NGC 2903 OSC RGB image (standard processing flow)

Rev E:  NGC 2903 OSC RGB image, starless

Rev F:  NGC 2903 OSC RGB image, inverted