Welcome! This tool lets you simulate the field of view of the Moon using your photographic or astronomical setup. Set your camera parameters, focal length and other options, then preview the result directly on the canvas. You can simulate mosaics, rotate the framing, and save your sessions with a simple shareable link.
📘 User Manual
Parameters
✳️ Pixel Size – Size of each pixel in microns (µm).
↔️ Sensor Width – Sensor physical width in mm.
↕️ Sensor Height – Sensor physical height in mm.
🎥 ROI Width / Height – Region of interest in pixels.
🔭 Native Focal Length – Your telescope/lens focal length in mm.
🔭 Telescope Diameter – The aperture of your optical system in mm (used to calculate focal ratio and sampling).
🔎 Barlow – Barlow multiplier (e.g. 2x).
🌫️ Seeing – Predicted atmospheric stability in arcsec (used for ideal sampling calculation).
🧩 Mosaic – Number of panels per side (e.g. 2 = 2×2).
✂️ Overlap – Overlap percentage between panels.
📅 Date – Date of the simulation. Phase and size will be updated consequently.
Controls
💾 Save a combined image (results + preview + simulation).
🔗 Copy a link with the full session setup.
🔄 Reset position and rotation of the red rectangle.
Workflow
- Select your camera or enter custom sensor data.
- Set focal length, aperture, Barlow factor, ROI, and **Seeing**.
- Pick a date or lunar phase to simulate the Moon.
- Drag or rotate the red rectangle to frame the scene.
- Enable mosaic grid for multi-panel planning.
- Use 💾 to save or 🔗 to share your session.
🔗 Saving & Sharing
Clicking 🔗 generates a unique URL containing all session parameters — including camera settings, focal length, lunar phase, FOV size, rotation, and position.
You can bookmark this link, save it in a note, or send it to a friend. Opening it will restore your exact setup.
📎 Lunar Calculations – Disclaimer
The lunar phase and apparent size displayed in this simulator are computed using SunCalc.js, a lightweight JavaScript library designed for calculating sun and moon positions and phases based on simplified astronomical algorithms. While SunCalc.js provides reasonably accurate results for general purposes, it does not account for all the complexities of celestial mechanics.
Lunar Phase Calculation: The phase of the Moon is determined by the illuminated fraction of its disk as seen from Earth. SunCalc.js calculates this using the positions of the Sun and Moon relative to Earth at a given time. The phase value ranges from 0 (new moon) to 1 (full moon). However, this method assumes a simplified model and does not consider factors like the Moon’s libration or the slight variations in its orbit, which can affect the precise appearance of the lunar phase.
Apparent Size Calculation: The apparent size of the Moon is influenced by its distance from Earth. In this simulator, the apparent size is calculated using the formula 384400 / distance, where 384,400 km represents the average distance between Earth and the Moon. This calculation provides a scaling factor that adjusts the Moon’s size relative to its average appearance. However, it does not account for the elliptical nature of the Moon’s orbit or its perigee and apogee variations, which can cause noticeable changes in its apparent size.
Time Considerations: To provide a consistent and user-friendly experience, the simulator evaluates the Moon’s phase and position at 18:00 local time for the selected date. This approach aligns with typical evening observations but may differ slightly from astronomical ephemerides that use specific times like UTC midnight or the exact moment of lunar phases.
Limitations: It’s important to note that this simulator does not model the Moon’s true orbital dynamics, including its elliptical orbit, inclination, or libration effects. These factors can influence the Moon’s appearance and position in the sky but are beyond the scope of this tool. As a result, minor discrepancies between the simulator’s output and precise astronomical data are expected.
For applications requiring high-precision lunar data, such as detailed astronomical observations or scientific research, more comprehensive tools and datasets should be consulted.