The THN stats DB can't list number of players in a clan who are online. (Unless I can persuade Zoltan to allow this information in the Neocron API.) However you can check ingame at a citycom of who's online in a clan.
You can see on this graph that the peak time for players being
online is around 8pm UK time.
To be fair to After Dark they taken a fair few ops over August considering the server has been quiet. Check their
clan stats page and you can see here
which clans that have successfully taken ops in the last 30 days.