Astro Pixel Processor by Aries Productions

Astro Pixel Processor or simply APP has been released on 2 june 2017

APP is a complete Deep Sky Image Processing application

On the 3rd of August 2017, Sara Wager was awarded with an Astronomy Picture Of the Day, or APOD, in which APP played a big role in processing:

Pelican Nebula Close-up by Sara Wager, APOD 2017-08-03
Pelican Nebula Close-up by Sara Wager, APOD 2017-08-03

Calibration, registration, normalization, integration and Hydrogen-alpha + Oxygen-III Bi-Color combination done with APP. Post processing in Photoshop.

A selection of images made by APP users:

Click on the images to view them full-screen with details.

I want to thank everyone that is part of the development of Astro Pixel Processor and everyone that has ordered a license. Thank you for you commitment to Astro Pixel Processor and your support in this special project.

Special thanks go out to Sara Wager for having created several video tutorials as well, thank you Sara 😉

Even though Astro Pixel Processor has just been launched, it can already compete with the best out there when it comes to data calibration, registration, normalization and integration, check this video tutorial to see APP’s capabilities on a complicated Hydrogen Alpha dataset of the Rosette Nebula…

This is just the beginning of Astro Pixel Processor, prepare yourself for more documentation to be created, more video tutorials, and an increasing amount of features to be added in the future, to process your data.

A complete Deep Sky Image Processing application…

 APP features:

  • image calibration with bias, dark, flat frames and bad pixel maps
  • accurate star analysis with very high star lokation precision (0,05 pixel for monochrome data) using Intensity Weighted Centroiding.
  • Registration with Dynamic optical Distortion Correction (DDC)
  • advanced Data normalization
  • advanced integration/stack engine including outlier rejection filters and the ability to output rejection, weight and normalization maps.
  • full drizzle support including bayer drizzle. The drizzle droplet and grid enlargement can be configured. And different drizzle kernels can be used, like point, square, tophat and gauss.
NGC 2174 - Monkey Head Nebula by Kees Scherer
NGC 2174 – Monkey Head Nebula by Kees Scherer, 10,5 hours of RGB exposure with a Canon EOS 6Da and a Skywatcher Esprit 100 f/5.5 refractor on his 10Micron GM2000HPS II mount. Completely processed with Astro Pixel Processor.


  • data interpolation algorithms for all different kinds of image transformations like Lanczos and Mitchell-Netravali algorithms.
  • choose different compositions for you stack before data integration. You can choose to integrate the entire field of view of all frames, or only the field of view of the reference frame, or even a crop of the reference frame.
  • directly integrate using another scale, so you can directly upscale or downscale the integration result.
  • the ability to project your data differently than the regular rectilinear projection for huge field of views after camera calibration (focal length, principal point). This is needed for Field Of Views (FOV) larger than 120 degrees.
180 degree MilkyWay mosaic by Ralph Wagter. Only 1 sub per panel, shot with a Canon EOS 6D camera and a Samyang 14mm F/2.8 objective. Top left: middle panel after distortion correction (notice the moustache distortion of the Samyang 14mm F/2.8 objective). Bottem left: middel panel after distortion correction, camera calibration and equirectangular projection. Top right: the three panels. Bottom right: the actual 180 degree mosaic, from north to southern horizon.
  • a very efficient light-pollution/gradient removal tool.
  • batch tools to rotate, resize, crop, uncrop, and even undebayer(!) your frames
  • can split your RGB data into separate channels for combination with monochrome channel data.


ngc5907 LRGB - Marco Verstraaten
NGC5907 by Marco Verstraaten, 12″ Ritchey Chretien & QSI583WSG & SX AOL active optics. LRGB data reduction and integration completely with Astro Pixel Processor.
  • ability to adjust FITS meta data
  • the possibility to multiply or divide your data with a certain factor or to add/remove a pedestal to/from your data
  • preview filter which different automatic stretch settings, background & highlights protected saturation adjustments, contrast increase, sharpening while protecting your stars and the option to reduce the stretch in the highlights, giving tighter stars and less saturated star cores and nebula.
Preview filter: the automatic DDP (Digital Development Process) stretch finds a suitable blackpoint and stretch parameter. You can use different presets for the strength of the stretch. Furthermore, you can boost saturation with background protection, enhance contrast, protect the highlights to reduce star size and over saturation. Finally you can sharpen the result while protecting your stars. All possible with one single filter.
  • using the preview filter, you can directly save all your results to FITS, TIFF or JPG formats including ICC color profiles for correct color management.
  • the RGB or Luminosity histogram of your data is always visible
  • tool for star color calibration
Barnard's Loop, M78, ldn1622
Barnard’s Loop, M78 & ldn1622 by Maurice Toet, 2 panel mosaic, Takahashi Epsilon E-180, Canon EOS 5D Mark II (BCF mod). Data calibration, registration, normalization and the 2 panel mosaic integration was done completely with Astro Pixel Processor.
  • a RGB composite tool with Luminance implementation for the creation of all kinds of composites, like LRGB, LHaRGB, or a Hubble Palette using your narrowband data (SHO).
  • a selective color tool with the ability to selectively adjust the colors in your images or/and selectively boost saturation and/or luminance.
  • all data processing in APP can be done on linear data. The selective color tool has no problem for instance with your linear data.
  • APP will run on any 64bits operating system where the Oracle Java Runtime is available. APP is installed together with the correct Java Runtime Environment (JRE), so the user doesn’t need to worry about this. Currently, complete installers for Linux (DEB & RPM), Windows (.exe) en MacOS (DMG) are available.
The interface of APP showing the Pleiades star cluster. Courtesy of Mabula Haverkamp.

With unique features…

Astro Pixel Processor has several features which are unique and innovative for Deep Sky astrophotography:

  • advanced image registration using true optical distortion correction
  • the ability to create huge mosaics automatically by solving the registration problem of all mosaic panels as one complete problem
30 panel RGB mosaic by Scott Rosen using APP’s mosaic capability. The illumination differences between the panels aren’t corrected purposely in this case, just to illustrate the rather complex mosaic calculation. 12 panels were shot with a Canon 6D and the other 18 panels were shot with a Canon 450D, both using a 50mm f/1.8 Olympus Zuiko lens. In the center you can find Polaris, at the top the Milky Way. And at the bottom, you can find Ursa Major. Most of the 30 panels have overlap with more than 10 other frames, making this an extremely difficult situation to get perfect registration for all frames.
  • advanced image normalisation using only the data areas that exactly overlap between the reference frame and the frame that needs to be normalised.
  • a new innovative technique called Local Normalization Correction or LNC. This will greatly improve data normalization in the complete stack before actual data integration.
  • Multi-Band Blending will remove stack artefacts in regular stacks or seams in a mosaic integration.
Cygnus, From North America Nebula to the Crescent Nebula. Data courtesy of Yves van den Broek. 18 panel HaRGB mosaic shot with a WO Star 71 apo, a Nikon D810a and a cooled monochrome Nikon D600. 38 hours of exposure in 9 panels for RGB and 9 panels for H-alpha. Completely processed in Astro Pixel Processor. In detail: data calibration using bias, artificial flats (Kang Weiss modelling) and Bad Pixel Mapping, mosaic registration with dynamic distortion correction and camera calibration, data normalization, mosaic integration with multiband blending and 8th degree local normalization corrections to remove the seams of the mosaic. Light pollution correction, background calibration, HaRGB composite. Stretched with APP’s preview filter including contrast and saturation.
  • a special and unique demosaic algorithm called: Adaptive Airy Disc that will reduce green/magenta cast in your RGB data, will improve sharpness and will make your stars rounder when compared to the well-known AHD and VNG algorithms.
A comparison of debayer algorithms. From left to right: BLN, bilinear with lots of artefacts and chromatic noise. AHD,Adaptive Homogeneity-Directed showing artefacts in the background and bad star shapes. VNG, Threshold-Based Variable Number of Gradients, showing less artefacts in the background but really bad artefacts at the star borders. AAD, Adaptive Airy Disc, showing the least artefacts in the background, no artefacts at the star borders, best resolution and least chromatic noise in the background.
  • demosaic algorithms for direct processing of monochrome narrow-band data (H-alpha, SII, OIII,…) acquired with One Shot Color (color CCD/CMOS, DSLR) camera’s.
  • chromatic aberration correction as part of RGB data calibration using a special registration model that will correct all forms of chromatic aberration to a very high degree.
  • a tool to correct vignetting in your lights/stacks using Kang-Weiss models with or without a geometric factor. The geometric factor is needed for optics consisting of several optical elements.
Rosette Nebula by Ivring Pieters, Michael van Doorn, André van der Hoeven, Rob Musquetier & Ruud de Vries. 18 hours of combined Hydrogen-Alpha exposure time from 5 different telescopes and cameras.. Top left: integration result from conventional normalization of the frames. Top middle: integration result using APP’s advanced normalization mode with Local Normalization Correction enabled. Top right: integration result using APP’s advanced normalization mode with Local Normalization Correction enabled and Multi-Band Blending enabled. Bottom: for each integration result, the normalization map is shown. The normalization maps shows the dispersion of all pixel stacks in the integration. The lower the value, the better the integration. Please note that MBB removes the stack artefacts and seams and that the advanced normalization plus the LNC algorithm gives much better data normalization.