What to Consider First ?
To figure out your own best time to post on Instagram, first take a look at these two major factors:
1. Your target follower demographics:
Adults who work the typical 9-to-5 job might be more likely to look at Instagram in the morning, whereas college kids who stay out late and pull all-nighters might be slightly more active on Instagram during those off hours.
Identifying your target audience can be a first step toward figuring out what time of day they like to check Instagram.
2. Time zone differences:
If you’ve got followers or a target audience from all over the world, then posting at specific times of day may not get you the same results as if you had followers who mostly all live around the same time zone.
For example, if most of your followers are from North America living in the typical North American time zones of Pacific (PST), Mountain (MST), Central (CST), and Eastern (EST), you could start experimenting with starting to post on Instagram around 7 a.m. EST and stopping around 9 p.m. PST (or 12 a.m. EST).
50% of the U.S. population is in the Eastern Time Zone, and the Eastern and Central combined represent almost 80% of the U.S. population.
Time Slots to Try
Despite all these different findings, you won’t know exactly what works best until you start experimenting and keeping track of engagement results. Again, it all depends on your target audience and how you’re using Instagram to connect with your followers.
You can start by experimenting with the following time slots for posting on Instagram:
Mornings, 7:00 a.m. - 9:00 a.m.
Morning hours are a good time to post because everyone is just waking up. Most people can’t resist checking their phones to see what they missed while they were asleep. After 9:00 a.m., however, you may see a bit of a drop in engagement due to regular work and school hours.
Midday, 11:00 a.m. - 2:00 p.m. Around the lunch hour is when people get a break to do what they want; that often includes checking social media.
Evenings, 5:00 p.m. - 7:00 p.m. After school and work, people get the chance to relax. People may start checking their phones while they sit in transit or in front of the TV just before dinnertime. Just be aware that you may be better off posting earlier around 5:00 p.m. or later at 7:00 p.m. rather than right in the middle (6:00 p.m.) when a lot of people are commuting home from work or eating dinner.
Mondays, Wednesdays, Thursdays, and Fridays seem to have the highest engagement according to the research sources above. Track the amount of likes and comments you get for each time slot and make adjustments as needed.
read more (dont want make the forum spammy ) 
https://coschedule. com/blog/best-times-to-post-on-social-media/
https://www.lifewire. com/best-time-of-day-to-instagram-3485858
I see
