The limit magnitude is 13.15, 12600 light-years from the center of the galaxy.

The location of the image is on the side of the Virgo cluster.

The M51 galaxy covers the entire sky of the green moon (Though only the core and its surrounding parts may be visible with enough brightness). You can imagine the scene of M 51 and the purple giant planet appearing at the same time on the night sky of this moon.

Task: Please find the remaining 39 galaxies in the image (M 101, NGC 5474, DDO 169, IC 4263, NGC 4707, UGC 8837, NGC 5585, NGC 4605, NGC 5866, NGC 5907,NGC 6140, NGC 6946, M 94 , M 106, UGC 7639, NGC 4144, NGC 4631, NGC 4656, NGC 3521, NGC 4618, NGC 4490, NGC 4386, NGC 4460, NGC 4559, NGC 4242, NGC 4248, M 64, M 108, NGC 3079, NGC  3198, NGC 2181, NGC 4725, NGC 4565, M 98, M100, NGC 4438, M 85, M90, Andromeda Galaxy)

Tips:

M 101: The easiest galaxy to find, located at the bottom left of M51b

 NGC 5474: Located at the lower right of the M51b galaxy nucleus, not far from the upper right of M 101

 DDO 169: Irregular galaxy, red-orange cloud-like, not far from the lower left of the green moon(unconfirmed)

 IC 4263: Located not far from the bottom right of the green moon

 NGC 4707: Irregular galaxy, in the form of blue clouds, located at the bottom left of the green moon

 UGC 8837: Irregular galaxy, in the form of red and blue clouds, located at the lower left of M101

 NGC 5585: Located not far from the lower left of M101

NGC 5866: Located not far below the bright yellow star at the bottom right of the green moon

NGC 5907: Located at the bottom right of the green moon and not far to the left of the bright yellow star

 NGC 4605: Located at the edge of the lower right corner of M51a

 NGC 6140: Located not far from the bottom right of UGC 5585

 NGC 6946: Located not far to the left of the main star of the current planetary system

 M 94: Located near the third cantilever on the upper right of M51a

 M 106: Located above the brightest blue star between M51a(looking to the right) and the green moon

 UGC 7639: Irregular galaxy, purple, located not far to the right of M 106

 NGC 4144: Located to the right of M 106

 NGC 4631: Located at the upper right of M51a

 NGC 4656: Irregular galaxy, located not far from the upper left of NGC 4631

 NGC 3521: Located not far from the bottom right of NGC 4631

 NGC 4618: Irregular galaxy, located at the bottom right of NGC 3521

 NGC 4490: Located not far from the upper right of M51a

 NGC 4386: Located to the right of NGC 4490

 NGC 4460: Located at the top left of the green moon

 NGC 4559: Located at the upper right of M51a, and the purple giant planet at the lower right (at the edge of the panorama)

 NGC 4242: Located not far to the left of the bright yellow star to the left of the green moon

 NGC 4248: Located at the bottom left of NGC 4242

 Black Eye galaxy, M 64: Located not far above M51a

 M 108: Located at the bottom left of the green moon and above the right of the bright blue star

 NGC 3079: Located to the right of M 108

 NGC 3198: Located on the upper left of M108, on the upper left of the two bright yellow stars

 NGC 2181: similar to a star, difficult to find, located to the left of M 108

 NGC 4725: Located at the upper right of the purple giant planet (at the edge of the panorama)

 NGC 4565: Located not far to the right of NGC 4725 (but the image should have been upside down at this time, so it is on the left), above the green moon

 M 98: Located at the upper left of the bright star at the upper left of NGC 4565

 M 100: Located at the upper right of M 98(The galaxies in this area are very dense, these galaxies form the Virgo Cluster)

 NGC 4438: Located at the top right of the M 100

 M 85: Located at the upper right of M 98

 M 90: Located at the upper right of M 85

Andromeda galaxy, M 31: Located at a dusty edge at the lower right of the M51a core, only half of the galaxy is visible. The Milky Way is not far from the upper left, at the first cantilever, very close to the core.  Although it is closer to M51 and has a higher apparent magnitude than the Andromeda galaxy, it is not visible due to the high brightness of the M51a core

 ＊Sunflower galaxy, M63: Located behind the green moon, Edge-On Galaxy, the appearance of this galaxy is close to M 64