Strange Object Near Arcturus

While setting up and monitoring Arcturus a strange object came into view travelling Right to Left. It took me by surprise so I only videoed the second half of the transit. I've no idea what it can be, but it's about 7 ArcSec diameter travelling at about 68 ArcSec/Sec.

Update 21/05/2019. Almost certainly a balloon of some sort.

Time stamp: 17:39 UTC May 16th 2019

M13 - Great Globular Cluster in Hercules

Scope: Sky Watcher ED80 DS Pro
Mount: Celestron Advanced GT mount
Camera: Altair Astro Hypercam 183C
Guide cam: QHY 5L-II-C
Guide software: PHD2 

Total of 2h 28m exposure

M101 Pinwheel Galaxy

The latest image of M101 taken over 2 nights

Scope: Sky Watcher ED80 DS Pro
Mount: Celestron Advanced GT mount
Camera: Altair Astro Hypercam 183C
Guide cam: QHY 5L-II-C
Guide software: PHD2 

Total of 1h 30m of 2m exposures.