aquila is a package designed to be a minimalist tool for initial steps of astrophotography data processing. There is a shortage of easy to use tools for Linux. Moreover, most tools in existence do not work well from terminal, which is a natural tool for managing and organizing hundreds of image files during stacking etc. Popular tools like IRAF are not friendly for quick use by amateur astronomers. aquila is intended to fill that void.
Currently, the package consists of following programs:
aqstackfor stacking and reduction of monochromatic CCD imagesaqlrgbfor compositing images from many filters into one color picture
Use option -h or -help to get the information below.
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}
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
- 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