What is best day to have sonogram of ovaries to determine what is ovulatory and what shouldnt be there?

Depends on: There's not 1 best day, it depends what you're trying to learn. If ttc what plan you are on: natural or stimulated cycle (they're different?) if monitoring leading up to ovulation then 1-2 days before anticipated works, if monitoring to confirm ovulation then 3 days afterward is better. Best time to check for 'abnormal' cysts is usually cd 3-5. Stimulated cycles need to be monitored more often.

Usually midcycle: Ovulation is about 14 days before menses but varies. Have doc get cycle history and choose a day before predicted ovulation then other scans as needed for timing. Can use OPK and call doc for scan to confirm. If meds, then scan after a few days of treatment. Review with doc. Best wishes.