NGC 3631 is a spiral galaxy in the constellation Ursa Major. It is located at a distance of about 35 million light years from Earth, which, given its apparent dimensions, means that NGC 3631 is about 60,000 light years across.
It was discovered by William Herschel on April 14, 1789. It is a grand design spiral galaxy seen face on. 
NGC 3631 features two principal spiral arms, which begin near the center. The two main arms branch into secondary arms with lower surface brightness.
The galaxy shows moderate-to-high star formation rate and bright HII regions are present in all the arms. At inclination of 17 degrees, the galaxy is seen nearly face on. 
Atomic hydrogen is detected mostly within the limits of the optical disc but also extends one and a half times the radius of the optical disk. 
NGC 3631 has weak diffuse X-ray emission. There are six candidates ultra-luminous X-ray sources in disk of the galaxy, two which have an optical counterpart. The nucleus of the galaxy hosts a supermassive black hole with mass 107.4 (25 million) solar masses, based on bulge luminosity. 
Four supernovae have been discovered in NGC 3631 from 1964 to 2016.  [Reference:  Wikipedia]

Capture Information:
The image was captured with the iOptron CEM120 mount, the venerable Meade 12" LX200 SCT OTA, and my QHYCCD QHY294m Pro mono CMOS camera at F7.16 (2182 mm FL)

Astronomik's Lum, Red, Green and Blue broad band filters were used.

Image Information -- 2024
LUM :  40 subs (3.33hr) on Mar 9th and 11th.
RED :  20 subs (1.67hr) on Mar 9th and 11th.
GRN :  20 subs (1.67hr) on Mar 11th.
BLU :   20 subs (1.67hr) on Mar 11th.
All exposures were at 5 minutes (300s) each, 1600 gain, 56 offset, 1x1 bin and -10C.

Processing was done with PixInsight, following (for the most part) Kayronjm's tutorial of Feb. 24th from several years back.
Lum filter was used to develop the Luminance image. R, G and B were collected for the color mix.
North is to the right (pretty sure), and this is a slight crop due to better placement of the image.

Comments:
This is the 1st time I’ve run at this target.  This image likely could have benefited from the addition of Ha.

ONE LAST THING:
This is the first image using the Starlight Xpress Lodestar Pro guide camera.  This camera is a lot newer than my old Lodestar (about 14 years), and claims to have better features.
I found that the setup could not achieve focus using the old “0.5x” reducer which made the guide system arguably 1091mm focal length.  And I had no luck finding a new reducer that could be used.  Consequently, I decide (with low expectations) to try guiding at the system focal length of 2182mm.  Fortunately, it worked!
There’s still some squirrelly-ness that I have to address.  One being the PHD2 guide software not starting up when called upon by the automation software.