After trying to mount the BloomSky directly on my backyard trellis post, I got another treated board and screwed it into the the top of the trellis.  One additional benefit was the solar panel would be facing the south.

At first, I was going to use the screw on the BloomSky mount to hold it in place.  It seemed to work fine but then started getting worried about wind.  So, I found a small board and screwed that to the treated board and then add screws into the mount and both boards.  That seemed to make more secure for wind.

I liked the resulting image much better.  There was a nice horizon line.  The wifi seemed to still work too.  I will have to monitor to see how everything works in this final mounting location.