Hi there, Matt Sergei here (do call me Matt, please) and can help you (former technical writer, Doc-To-Help Certified Trainer, 26 years a webmaster and IT developer. 15 years a WordPress pro and 7+ years scripting web charts).
You have several tasks to create and implement so:
1. I believe you have all your astro chart calculations e.g. formulas for creating the charts. You are the SME (Subject Matter Expert) here, I can only create your charts based on data.
2. Then a WordPress requirement. Charts in WordPress are not well implemented (even in plugins, rare exceptions exist) so your charts will need to be made with special additional content type.
Most likely open source (read: free) D3.js library will be used since I know it really well and know how I would create astro charts with it.
3. And then you also have user management (WordPress will be fine) with several user levels, potential subscriptions (paid?), their charts (can be more than one) etc.
So first a good data model needs to be created (user table, data table, charts table) and then proper features built (most likely WordPress plugins too, not just custom content types).
Yes, I can do that all though this is really a summertime project.
Please let me know more about the above and additional details you envision for your website. Then I'll update the bid with milestones.
Best Regards and hope you’re safe,
Matt