From the NASA site
"The new launch window is targeted for Wednesday, Sept. 18 between 10:50 to 11:05 a.m. EDT from the Mid-Atlantic Regional Spaceport Pad-0A at NASA's Wallops Flight Facility in eastern Virginia".
"On Sunday, Sept. 22, NASA Television coverage of rendezvous will begin at 4:30 a.m. and will continue through the capture and installation of the Cygnus spacecraft. Capture is scheduled for about 7:17 a.m. with installation of the craft beginning about 9 a.m."
There are some ISS viewings from the 18th through the 22 in the AM hours in upper East North America