Distribution function of the stellar photometry data from the B-band image including Czernik 30. The color bars on the right show the values of the normalized number density for the background (left) and the membership probability for the colors of dots (right). Black dots are the locations of stars without consideration of their brightnesses, red dot is the obtained center of Czernik 30 and the red circle is radius ﹩2\buildrel{\,\prime}\over{.} 3﹩.