There are only a few galaxies around the Big Dipper that are going to be obvious in an image taken with a 50mm lens and at the small scale of the image you've posted I can't really tell where you had the camera pointed.
Actually, I took a copy of your image and ran a blind solve on Astrometry.net and it came up with the following solution:
Center (RA, Dec): (229.120, 52.359)
Center (RA, hms): 15h 16m 28.918s
Center (Dec, dms): +52° 21' 30.903"
Size: 26 x 17.3 deg
Radius: 15.618 deg
Pixel scale: 156 arcsec/pixel
Orientation: Up is 167 degrees E of N
I've also attached the labeled image that was created by Astrometry.net and it appears that you really weren't pointed toward any galaxies in the Big Dipper. Sometimes it can be hard to tell exactly where the camera is pointed when using a simple star tracker.
It looks like the galaxy NGC 5866 (the so-called "Spindle Galaxy") which has been identified as the "missing" M102 was just about in the center of your image. But that is a 10th magnitude object that is only 2.8 arc minutes in width (very thin, edge-on spiral galaxy).
Here is a link where I imaged the galaxy M51 using a 105mm lens, so with a 50mm the galaxy would be even harder to see.
Edited by james7ca, 26 May 2019 - 11:58 PM.