Thunder Storm Artefacts

Playing with the tripod and the camera last night during a thunderstorm, ISO 1000 setting and a very slow shutter speed to start..and then moving the apeture and speed around a bit. 3-4 weird spots that seem to be in some frames and not in others. Probably dust spots on the sensor? Not sure but they seem to change place. The sequence is up on photobucket. I never did get a bolt of lightning. The 1995 Camera Canon EOS has limited program functions and I am still learning to use it. Tell me what you think. I had cleaned the lense and filter prior to use and there are no obvious flaws in either.
For the record taken in Edmonton Alberta Canada at around 1030-11pm facing due West and moving to the >N With the 1st picture Left SW and Last Nw.
(The Big Red smear is a cell tower) What the blob is I have not a clue.
Knowing the chances are slim to none I decided to try anyway..because you never know the definitive photo is always only a click away.i305.photobucket.com...i305.photobucket.com...[url ]http://i305.photobucket.com/albums/nn235/sunray06/Faded3.jpg[/url]i305.photobucket.com...http:// i305.photobucket.com/albums/nn235/sunray06/Moving4-1.jpgi305.photobucket.com...i305... .photobucket.com/albums/nn235/sunray06/Moving4.jpgi305.photobucket.com...i305.phot... obucket.com/albums/nn235/sunray06/Second3.jpgi305.photobucket.com...i305.photobucke... t.com/albums/nn235/sunray06/Standing3.jpgi305.photobucket.com...