The Hub

It's been a while since I posted about this (possibly years) and we've garnered some new members so I thought I'd post again.

I've written some software originally to calculate orbital characteristics around any gravitational mass, but with my own needs and the suggestions of others, it has grown considerably and does much more. It is available for Windows and Linux (both platforms in 32-bit and 64-bit versions) and the Raspberry Pi. Oh yes, it's free. It's written so Sci-Fi authors can get the calculations correct and avoid guessing.

Current features:
N-Body Centre of Gravity calculate centre of gravity for any number of gravitational masses
Constant Acceleration - all 5 components of the constant acceleration equations can be deduced and converted
Free-Fall distance and final velocity for increasing rate of acceleration over any gravitational mass for any duration
Distance/Speed/Time calculations and conversions
Schwartzschild and Photon Sphere radii calculated as a factor of mass
Synodic Periods calculated from orbital distances (and central mass)
Synodic Periods calculated from orbital periods
New Objects added to database - six stars and one more asteroid
Automatic Calculation wherever it makes sense, so you don't have to hit a 'calculate' button
Copy to Clipboard on most result screens
Database Stats now provides totals
Repeat Last Calculation now works even if you've removed both the host mass and satellite mass from the database
Import Data recognises v1.x import files and databases (so you can import directly from an old database)
Export Data to prune a database, separate project data or to share with friends
Preferences to control update checking, restoring window sizes and positions
Gravitation and Motion to calculate gravity, escape velocity and gravitational acceleration at the surface and at an elevation
Lagrange Points calculated as distance from the surfaces of the host and satellite mass
Two-Body Orbits taking into consideration the masses of both host and satellite
Hohmann Transfer Orbits for low-energy migration
Distance Between Two Stars using star-chart coordinates
Apparent Magnitude of a star from another star
Distance from Period when all you know is the host mass and and the orbital period
Satellite Footprint from Altitude
-- Visible Surface of host mass as %
-- Latitude spread of the footprint across the surface
-- Diameter of footprint
-- Radius of footprint
-- Surface Area of footprint in square kilometres
-- Maximum Period of Visibility of satellite from the ground
Visibility over Horizon How far from an object (e.g. mountain) can you be and still see it?
Age from Orbit calculate someone's apparent age from local years
Age and Weight on Solar System Planets
Calculate Habitable Zone (a.k.a. Goldilocks Zone) around a star
Time Dilation from Velocity where velocity is a factor of the speed of light
Time Dilation from Orbit factoring both gravitational time dilation and acceleration time dilation
Context-sensitive Help
Zoom-in, Zoom-out if things are a little hard to read
Password Generator to generate very strong passwords for those pesky internet logins
Multi-Platform it runs on Windows, Linux & Raspberry Pi
Portable means it doesn't have to be installed - just unzip and run. Can be run from a USB stick.

I'm currently working on adding Cycler Orbits  .

You can read about it here: https://philip-p-ide.uk/doku.php/blog/articles/software/orbital_calculator
The downloads page (also linked at the bottom of the description page) is here: https://philip-p-ide.uk/doku.php/blog/aardvaark/downloads