What did I photograph?
A contrast stretch reveals stars down to magnitude 4 or 5.
The stars you asked about are Deneb (center) and Vega (bottom).
The constellation in the center and below is Cygnus; we also see Cepheus at upper right and part of Draco at lower right.


The stars appear as blobs 10-12 arcminutes wide due to several factors:


Rotation around the north celestial pole, to the right of the upper right corner of the image. In your 30 second exposure, Deneb and Vega drifted 5-6 arcminutes in the 5 o'clock direction.
Diffraction due to finite aperture. The width of the ring pattern is inversely related to the width of the aperture. These rings are consistent with a 2-3 mm aperture.
Optical aberrations such as coma, increasing toward the edge of the image.
Vibration as noted in another answer.