With most Newtonian reflectors, you will find the image is upside down and left / right are also opposite. This is normal and nothing to worry about. This is simply the effect of using mirrors in this layout.
It can be over come with erect images eye pieces. But by doing this , the light is travelling through more glass and will degrade the image.
Its simply a case of thinking opposite when you are centering a target. At the end of the day all Planets and stars are round. So whether they are upside down or not will not make the image less accurate