The red smudge at the top of the right image is where a red light leaked through to the film. This can happen when you use an illuminated reticle eyepiece with an off-axis guider, or a red flashlight pointed in the direction of the camera. Planes, trains, and Faint Fuzzies. No, those aren't UFOs lurking in these images. Just pesky planes and red lights.
Planes are a big problem with wide field exposures.
Guiding on wide field exposures isn't as critical, so you can risk taking your eye away from the eyepiece to check. This doesn't affect the exposure at all. The black smudge on the left image is dust or dirt on the camera lens. Make sure your lens is clean before you shoot, and make sure to use cleaning paper safe for coated lenses. An air blower works well also.