baby dancing on the last fertile day

Jessica
My husband and I are officially TTC! However we haven't been able to try due to him being overseas working. I'm tracking with OPK/CM and <a href="https://play.google.com/store/apps/details?id=com.glow.android">fertility apps</a> and my husband won't arrive until my last fertile day. 
Is the last fertile day your ovulation day? Has anyone had success with such a small window of time? Im trying not to get discouraged because his schedule won't allow us to try again until Oct. 
I would love to hear from you all! Thanks!