Hi, I have a celestron nexstar 8 se and like many had a lot of questions about this setup. Searched for weeks and read every post and watched every video. Bought the items last week and follow directions and could not get it to work. After many hours of troubleshooting replacing wires, adapters, null modem or not I was ready to give up. But as really stubborn people do, this morning I thought "Can't let this thing beat me" so I went on modifying one thing at a time, one setting, cable etc. after a couple hrs I heard the sound and it connected, but couldn't figure what It was. Then it hit me, powwww, the bluetooth adapter MUST be off during alignment, once aligned, turn it on, voila it works. Funny how something so simple could cause so much trouble. I am not saying this will solve everyones issue, but I had not seen anyone anywhere bring this up. So, if you have a nexstar and you're ready to throw your scope out a window, give this a try!