Tenmon is a FITS/XISF image viewer with multithreaded image loading.
It is intended primarily for viewing astro photos and images.
This is free and open source software.
Key Features
- Supports the following formats:
- FITS 8, 16, 32 bit integer and 32, 64 bit float.
- XISF 8, 16, 32 bit integer and 32, 64 bit float.
- RAW CR2/CR3, DNG, NEF.
- JPEG, PNG, BMP, GIF, PBM, PGM, PPM and SVG images.
- Using same stretch function as PixInsight.
- OpenGL accelerated drawing.
- Index and search FITS XISF header data.
- Quick mark images and then copy/move marked files.
- Convert FITS <-> XISF.
- Convert FITS/XISF -> JPEG/PNG.
- Image statistics mean, media, min, max.
- Support for WCS.
- Thumbnails.
- Convert CFA images to colour – debayer.
- Color space aware.
- Histogram.
- Scripting.
- Cross-platform support – runs under Linux, macOS, and Windows.
Website: nouspiro.space
Support: Code Repository
Developer: Dušan Poizl
License: GNU General Public License v3.0

Tenmon is written in C++ and C. Learn C++ with our recommended free books and free tutorials.
Related Software
| Astronomy Software | |
|---|---|
| Stellarium | A virtual planetarium |
| Gaia Sky | Astronomy visualization desktop and VR program |
| Celestia | Real-time space simulation |
| AstroImageJ | Tool for astronomical image analysis and precise photometry |
| Skychart | Prepare different sky maps for a particular observation |
| KStars | Desktop planetarium for KDE |
| OpenSpace | Interactive data visualization software |
| Aladin Desktop | Interactive sky atlas |
| Virtual Moon Atlas | Real-time moon observation |
| Ginga | FITS image viewer and toolkit |
| Digital Universe Atlas | Standalone 4-dimensional space visualization application |
| XEphem | Motif based ephemeris and planetarium program |
| mars-sim | General purpose simulator |
| Cosmonium | 3D astronomy and space exploration program |
| Tenmon | FITS and XISF image viewer, converter and indexer |
| Kosmorro | Calculate your ephemerides |
| Astra | Observatory control system |
| astroterm | Terminal-based star map |
| Skyviewer | Displays HEALPix-based skymaps |
| skyterm | Terminal-based astronomy program |
| ORSA | Framework for celestial mechanics investigations |
Read our verdict in the software roundup.
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