Fchart3

Fchart3 is a Python project for creating high-quality astronomical finder charts and maps.
It uses data from Stellarium, KStars, HNSky and Gaia-based deep star catalogues (≈300 million stars up to ~16–17 mag).

It can generate:

• Offline charts with output to PDF or TikZ.
• Online interactive charts – the same engine is used in the CzSky project.

Online interactive version (CzSky)

Interactive web charts using the fchart3 engine are available in the CzSky project:

• CzSky Chart

Features

• Deep-sky finder charts based on Gaia-derived star catalogues (hundreds of millions of stars).
• Deepsky catalogue with hundreds of thousands objects (from HnSky)
• Rendering of planets (including the Sun and Moon) and planetary moons, with:
  • Realistic planetary radii and phases.
  • Saturn’s rings with current orientation.
  • Optional moon magnitudes and optimised label placement.
• Horizontal (alt-az) and equatorial coordinate support, including:
  • Horizon and horizontal grid.
  • Optional equatorial grid in horizontal view.
  • Cardinal direction markers (N, E, S, W).
• Enhanced Milky Way rendering (outlined and shaded, including high-resolution variants).
• Flexible configuration of magnitude limits, fonts, labels and map legends.
• Output to PDF and TikZ for high-quality printing and LaTeX integration.
• Used as the map engine of the CzSky online star atlas.

Install

The recommended way is to install from the Git repository into a virtual environment:

git clone https://github.com/skybber/fchart3.git
cd fchart3

# (optional but recommended)
python3 -m venv venv
source venv/bin/activate

# install fchart3
pip install .

On some systems you may need development packages for Cairo and other libraries (e.g. libcairo and libicu on Linux) before installing.

Run

To see command-line options:

fchart3 --help

Generate a simple finder chart for the Crab Nebula:

fchart3 M1

Generate a complex chart of the M39 region (m39.pdf):

fchart3 -width 190 -height 270 -fieldsize 40 -limstar 9 -limdso 9 \
  --show-nebula-outlines --show-enhanced-milky-way \
  --font-style-bayer bold --font-style-dso italic \
  --flamsteed-numbers-only --show-equatorial-grid \
  --hide-map-orientation-legend --hide-map-scale-legend \
  m39

Generate a complex chart for the M39 region with output to TikZ (m39.tikz):

fchart3 -f m39.tikz -width 190 -height 270 -fieldsize 40 -limstar 9 -limdso 9 \
  --show-nebula-outlines --show-enhanced-milky-way \
  --font-style-bayer bold --font-style-dso italic \
  --flamsteed-numbers-only --show-equatorial-grid \
  --hide-map-orientation-legend --hide-map-scale-legend \
  m39

Data files

This repository also contains the following catalogues in the data/catalogs directory:

• bsc5.dat – catalogue of bright stars
• constbnd.dat – Catalogue of Constellation Boundary Data
• constellationship_western.fab – western constellation lines from Stellarium
• milkyway.dat – outlined Milky Way
• milkyway_enhanced.dat – shaded / enhanced Milky Way
• deep_sky.hnd – catalogue of deep-sky objects from HNSky, created by Han Kleijn (https://www.hnsky.org/software.htm)
• namedstars.dat – catalogue of named stars from KStars
• outlines_catgen.dat – nebula outlines from OpenNGC
• PGC.dat – catalogue of PGC galaxies
• PGC_updates.dat – updates to the PGC catalogue
• starnames.dat – star names from KStars
• stars_0_0v*.cat – Gaia-based deep star catalogues from Stellarium
• unamedstars.dat – catalogue of unnamed stars from KStars

Authors

• Vladimir Dvorak – fchart3
• Michiel Brentjens – original author of fchart.
• Austin Riba – modern fchart for Python 2.7 + NumPy: https://github.com/Fingel/fchart