I have a Canon EOS 1200D/Rebel T5. I'm an amateur phtographer and still learning. After reading a lot about astrophotography, I tried my hand at it. I took a trip to a relatively dark place, set up on a tripod, and started taking shots using my phone connected to the USB port as a remote release/intervalometer. I took 100 shots at different places, under different conditions. Every single shot, no matter whether the stars are completely in focus or not, showed a sort of streaking in random directions (not star trailing. I used the 600 rule). Here are some examples: https://drive.google.com/open?id=0B802HQPuk5MlRTJJZEJfM2Z3REU
I have a suspicion that this shaking is being caused by the camera shutter itself. I've tried searching online for others with the same problem, but my Google-fu hasn't helped so far. Is this some kind of issue with the 1200D or is it just my camera?
P.S. Note that since I have low reputation, I can't post more than 2 links. I'll make a Google Drive folder containing a few more examples if anyone wants, and I've edited out the links in the question itself.