Celestial Sphere

Overview

Celestial Sphere is an interactive web application that provides a neat and user-friendly interface for drawing and visualizing diagrams on a sphere. The tool is specifically designed to help students and educators easily learn and engage with spherical diagrams, which are commonly used in spherical astronomy, geometry, and coordinate systems.

Rather than struggling with complex mathematical notation or static textbook diagrams, users can dynamically create, manipulate, and explore geometric shapes and astronomical concepts in real-time on an interactive 3D sphere.

Core Features

Interactive Point & Shape Management

• Add Points: Left-click on the sphere to add points
• Select & Deselect: Click points to select/deselect or use Shift+Click for multiple selections
• Move Points: Drag selected points across the sphere
• Rename Points: Type to name selected points
• Delete Points: Remove unwanted points with Delete key
• Hide/Show Points: Toggle visibility with Ctrl+H without losing data

Geometric Construction Tools

• Great Circles: Draw great circles with a selected point as the pole (. key) or with 2 selected points (Shift+.)
• Small Circles: Create small circles through 3 selected points (, key) or with a pole and point (Shift+,)
• Arcs: Connect points with great circle arcs by right-clicking between selected points
• Diametrically Opposite Points: Generate the opposite point on the sphere (/ key)
• Point Snapping: Snap points onto nearby circles (Shift+drag)

Advanced Controls

• Grouping: Organize points into groups (Ctrl+G) for easier manipulation
• Properties Display: View coordinates of selected points and geometric properties
• Locked Points: Mark points as non-movable or non-removable
• Triangle Properties: View properties of triangles formed by 3 selected points
• Circle Properties: Inspect great circle and small circle parameters when selected

Visualization & Navigation

• Coordinate Grid: Toggle on/off for reference
• Zoom Control: Mouse wheel or slider (50%-200% range)
• Rotation Control:
  • Middle mouse button to drag and rotate
  • Sliders for precise x, y, z axis rotation (Ctrl+A, Ctrl+S, Ctrl+D)
• Pan & Zoom: Intuitive controls for exploring complex diagrams

File Management

• Save Diagrams: Export as .json files for later editing or sharing
• SVG Export: Save diagrams as vector graphics for use in presentations or publications
• Load Diagrams: Open previously created diagrams
• Fresh Start: Create new diagrams with a single click

Technical Architecture

Frontend Stack

Built with Rust and Dioxus compiled to WebAssembly for high performance:

• Rust: Type-safe, memory-safe systems programming language
• Dioxus: Modern, reactive web framework similar to React but with Rust’s performance
• WebAssembly: Runs efficiently in the browser without server requirements
• CSS: Custom styling for intuitive UI

Language Distribution

• Rust 96.5%: Core application logic and geometry computations
• CSS 3.5%: User interface styling

Use Cases

For Students

• Practice spherical geometry concepts
• Visualize celestial coordinates (RA/Dec, ecliptic, galactic)
• Understand great circles and small circles
• Explore spherical triangles and their properties
• Learn positional astronomy concepts

For Educators

• Create interactive teaching materials
• Demonstrate spherical geometry visually
• Export diagrams for presentations
• Build custom problem sets
• Show real-time geometric relationships

For Astronomers

• Design celestial coordinate diagrams
• Visualize observational geometry
• Plan observations and field positions
• Document astronomical concepts
• Create publication-quality diagrams

Keyboard Shortcuts Reference

Shortcut	Action
Click	Add/Select point
Shift+Click	Select multiple points
Delete	Remove selected points
Type	Name selected point
Right-click	Draw/remove arc between points
Scroll	Zoom in/out
Middle-drag	Rotate sphere
/	Place diametrically opposite point
.	Draw great circle with pole
Shift+.	Draw great circle through 2 points
,	Draw small circle through 3 points
Shift+,	Draw small circle with pole and point
Shift+drag	Snap point to circle
Ctrl+H	Hide/show point
Ctrl+G	Group points
Ctrl+U	Ungroup points
Ctrl+A/S/D	Rotate sphere (x/y/z)
Esc	Deselect all

Future Enhancements

The project has several planned features:

• Distance-based Point Placement: Add points at specific distances from selected points
• Angle-based Point Placement: Place points at specific angles
• Coordinate Input: Add points at given coordinates directly
• Circle Intersections: Snap to intersection points of circles
• Multiple Small Circles: Create multiple small circles sharing a pole
• Advanced Snap Features: Enhanced snapping for arcs and complex constructions

Building from Source

The project is built with Dioxus and can be built from source following the Dioxus deployment guides.

Impact & Community

Celestial Sphere has become an essential tool in the astronomy education community, particularly for:

• IOAA (International Olympiad on Astronomy and Astrophysics) preparation
• University spherical astronomy courses
• High school astronomy clubs
• Astronomy Olympiad training programs
• Research and visualization projects

The application democratizes access to professional-quality spherical diagram tools, making them freely available to students and educators worldwide.