AppImage
- Download Stable x86_64 / PC and ARM64 / Rpi / Mac
Click here to see all AppImage releases.
curl -L https://github.com/gronki/aquila/releases/download/stable/aquila-$(uname -m).AppImage -o aquila
chmod +x aquila
# test
./aquila
sudo install aquila /usr/local/bin/aquilaSnap
sudo snap install aquila
sudo snap alias aquila.lrgb aqlrgb
sudo snap alias aquila.stack aqstack
sudo snap alias aquila.cli aqcliaquila is a command-line toolkit for astrophotography data reduction and compositing on Linux. While graphical tools exist for this workflow, they rarely integrate well with the terminal — the natural environment for batch-processing hundreds of FITS files, writing reproducible pipelines, and automating nightly runs. Aquila is designed to fit into that world: fast, scriptable, and unobtrusive.
Currently, the package consists of following programs:
aqstack(via snap:aquila.stack) — stacking and calibration of monochromatic CCD frames (bias, dark, flat, alignment, sigma-clipping)aqlrgb(via snap:aquila.lrgb) — compositing multi-filter data into colour images with luminance, white-balance, and stretching controlsaqcli(via snap:aquila.cli) — a scripting interpreter for building full end-to-end image processing pipelines
To build the program on Ubuntu/Debian, first install the dependencies:
apt-get update && apt-get install -y --no-install-recommends cmake make gcc g++ gfortran libreadline-dev pkg-configManual build and installation:
mkdir build && cd build && cmake .. -DCMAKE_BUILD_TYPE=Release -DAQUILA_OPENMP=On -DCMAKE_INSTALL_PREFIX=/opt/aquila && cmake --build . && sudo cmake --install .Remember to add to your .bashrc:
export PATH="${PATH}:/opt/aquila/bin"
export LD_LIBRARY_PATH="${LD_LIBRARY_PATH}:/opt/aquila/lib/aquila"Use option -h or -help to get the information below.
aqstack handles the calibration and stacking side of the workflow: it subtracts bias, dark, and flat frames, identifies and corrects hot pixels, optionally aligns frames, and combines them using your choice of average, median, or sigma-clipped mean. It is designed to run efficiently even on large frame sets, with temperature filtering to keep only frames from the same thermal session and optional resampling for drizzle-style oversampling.
usage: aqstack [STRATEGY] [OPTIONS] FILE1 [FILE2 ...] -o OUTPUT
STRATEGY can be: bias, dark, flat, process, align, final
-o/-output FILENAME specifies the output filename
-average stack by average value
-median stack by median
-sigclip stack by 3-sigma clipped average
-align [METHOD] align frames (isometric). METHOD can be:
polygon: quadrangle matching {def.}
gravity_only: use gravity align method
gravity: use polygon matching and fine-tune
using gravity
-ref FILENAME align to this frame rather than first frame
-resample [FACTOR=1.5] resample before stacking (only with -align)
FACTOR is scale to be applied
-norm[alize] normalize to average before stacking
-no-stack process but do not stack images
-suffix/-S SUFFIX suffix that will be added to file names
when using -nostack {def.: _r}
-temp/-T TEMP [DT=0.5] stack only frames with given CCD temperature
DT gives allowed deviation in temperature
in Celsius
-bias FILENAME subtract this master bias
-flat FILENAME remove this master flat
-dark FILENAME remove this master dark
[-no]-hot [SIGMA=5.0] find hot pixels on dark and correct them
in the image frames (if dark is given) {def.: ON}
[-no]-hot-only do not remove dark, just correct hot pixels
{def.: OFF}
[-no]-darkopt [SIGMA=5.0] optimize dark to minimize correlation
if sigma is nonzero, only background will be used.
SIGMA=0 forces to use all pixels {def.: OFF}
[-no]-dirty-dark subtract bias from dark (only if not done before!)
{def.: OFF}
aqlrgb takes calibrated, aligned frames from multiple filters and combines them into a colour image. It supports the classic LRGB workflow — using a high-SNR luminance channel to sharpen the colour data — as well as narrowband palette compositing. It can equalise colour balance across channels, suppress background gradients, and apply nonlinear stretches (sqrt, asinh, log) before writing the result to FITS or PNG.
prepares the aligned images for RGB processing
usage: aqlrgb [L] R G B [-o FILE] [options]
R, G, B are color frames and L is optional luminance
-o/-output specifies the output file name
(allowed formats: fits, png)
-split save as 3 files fits rather than one cube
for example, if image.fits is given to -o, three files
image.r.fits, image.g.fits, image.b.fits will be written
-smooth [FWHM] smoothes color while preserving luminance
if FWHM not given, default value (2.5) will be used
-wb/-equalize attempt to make stars white
(works best if background is small)
-bg/-background attempt to make background black
(do not use for strong nebulosity)
-sqrt/-asinh/-log compress the image levels before saving
-sqrt2/-asinh2/-log2 same but using luminosity
(boosts star colors but can kill some details)
-h[elp] prints help
aqcli is a small domain-specific language for writing image processing pipelines. Rather than stringing together shell commands or writing Python glue code, you can express a full reduction workflow — loading frames, stacking, compositing, stretching, saving — as a readable script that runs top to bottom.
The language is expression-oriented: operations return values that can be assigned to variables or chained with the pipe operator %. Routines accept positional and keyword arguments; arrays of frames flow through pipelines element-wise.
lights = path("lights/L_frame_00{1,2,3,4,5,6,7,8}.fits") % file()
stars = findstar(lights)
alignments = register(stars, stars % item(1))
! alignment will be applied here once projection is in place
stack(lights, method: "average") % save("stack_L.fits")
Lines beginning with ! are comments.
S = file("stack_S.fits")
H = file("stack_H.fits")
O = file("stack_O.fits")
R = mix(H, 0.9, S, 3)
G = mix(H, 0.9, O, 1, S, -0.8)
B = mix(O, 3.3)
rgb = lrgb(H, R, G, B)
rgb % save("sho.fits")
The pipe operator % passes the result of the left-hand side as the first argument of the right-hand side, making it easy to build readable processing chains without intermediate variables.
- 210111: removed flux ratios, changed triangles to quadrangles
- 210109: auto-flip, polygon align
- 210104: dark optimization (simple), cleaning dark from bias
- 210103: hot pixels are corrected when dark is loaded
- 200717: hot pixel correction
- 200716: now temperature filter is before loading images, which saves memory
- color images
- large image handling
- use 32 bits for image storage
- more non-linear distortions
- proper drizzling
- better control over colors
- LRGB and edit commands