After reviewing my images of the 7th, I discovered that what I thought was light reflecting off my finder scope into the camera lens was actually amp-glo. It was present on both the lights and darks. After a lot of trouble shooting and posting on Canon Astro Yahoo Groups and CN, I got feedback that helped me pinpoint this problem. Gary Honis, who modified my XSi, also responded that this was my problem. Thanks to all who fed back to me.
For other noobs out there, this might help you avoid making some of my mistakes. First, EOS utility will not allow triggering the shutter if you have mirror lock up enabled in the XSi Custom Functions. It must be disabled in order for EOS to trigger the shutter.
Since I had lock up enabled, the only way I could get EOS to open the shutter and take a frame was to open Liveview. However this window should never be open when shooting as it generates a lot of heat from the amplifier which shows up as glow on all images shot while Liveview is open.
I have also downloaded a free trial version of BackyardEOS to evaluate for my next imaging session now that I have everything working well. Daylight use of the program makes it appear to be superb!
More to come.