- Astronomical Image Processing
- Astronomy Image Processing Software For Macbook Pro
- Image Processing Software Wikipedia
Cyanogen Imaging® MaxIm DLTM is the complete integrated solution for all of your astronomical imaging needs. Whether you are collecting and analyzing science data, or making beautiful portraits of the night sky, MaxIm DL Pro includes everything you need. Product levels available: MaxIm LT ($199 SBIG camera control, webcams, and basic processing only), MaxIm DL IP ($299 image processing only. Astro Pixel Processor: Advanced image processing software for Deepsky and Widefield Astrophotography. Stark Labs Nebulosity: Designed to be a powerful, but simple to use capture and processing application. PixInsight: Advanced Image Processing. PixInsight is a modular, open- architecture, portable image processing platform. Advanced Image Processing Software for Astrophotography. StarTools is a powerful new type of image processing engine. It tracks your signal's noise component as you process. The result is cleaner images, more detail, ease of use, and unique advanced post-processing power compared to any other software.
Lynkeos is a Cocoa (Mac OS X) application dedicated to the processing of astronomical (mainly planetary) images taken with a webcam through a telescope. It runs on Intel Macintoshes. It is optimized for vectorized instructions sets (SSE) and for multi-processor and multi-core machines. Professional Astronomy Telescope Control Software for Mac. Version 8 includes a 36,000 object, up-to-date, cross-referenced database built from various source catalogs. Starry Night 8 supports all telescopes that are supported by Ascom. Plus, connect SkyFi 3 with Starry Night too.
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FITS Image Viewers
- Image viewers for PC and Macs - an extensive listing of commercial and freeware image processing software compiledby the Astronomy Education Committee.
- Aladin - Interactive Sky Atlas
- APLpy - Astronomical Plotting Libraryin Python is a Python module aimed at producing publication-quality plots of astronomical imaging data in FITS format.
- Aperture Photometry Tool -interactive software tool for visualizing and performing aperture photometrymeasurements on astronomical images.
- ASTAP: viewer, image stacker, plate solver This program, available as an executable on Windows, Macs and most varieties of Linux, supports 8, 16, and 32 bit integerimages and also 32-bit floating point. including images using FITS compression. Users can determine the astrometric properties of images, stack and display them,including blind solving of the astrometry of each image using the GAIA database.
- AstroImageJ: processing, modelling and plotting astronomical image data in one package based upon the ImageJ Java library.
- Avis FITS Viewer - a FITS viewer for Windows. Only reads 8 and 16 bit FITS images.Converts to RAW, TIF, TGA, BMP, and JPEG formats
- Clearsky viewer- a javascript library for viewing a FITS image. Features include multiple regions of interest, stats, contrast, magnifying glass andmore.
- ds9 (SAOImage ) - astronomical visualization application from SAO
- FITS Liberator - a plug-in for Adobe Photoshop for manipulating FITS format images. Also works withPhotoshop Elements 2. Includes a short introduction toastronomicalimage processing.
- Fits4Win2 Viewer (shareware with free beta version)- a FITS viewer for Windows. Works as an extension to Windows Explorer and includessupport for viewing thumbnail images of FITS files.
- FitsPlug v2.0 (shareware with free beta version)- a FITS plug-in for Adobe Photoshop for Windows
- FITSview - FITS image viewer from NRAO
- fv - FITS file viewer and editor (supports FITS images and FITS tables)
- GAIA - an image display and analysis tool from the U.K. Starlink Project. It is a derivativeof the ESO SkyCat tool
- giv - A cross platform (posix andWindows) image viewer designed especially for scientific vision and computational geometry. Supports interactivebrightness and contrast adjustment of 2D images and 3D cubes in various dataformats, including FITS. Also supports drawing vector graphics on top of the image.
- GLnemo2 - aninteractive 3D visualization program for n-body snapshots which supports2D and 3D FITS data, as well as other data formats. GLnemo2 is open source, multi-platform (linux, MacosX, windows), and uses qt5 API and openGL hardware acceleration.
- ImageJ - a public domain, Java-based image processing program developed at the National Institutes of Health. ImageJ was designed with an open architecture that provides extensibility via Java plugins and recordable macros. It supports 8-bit and 16-bit integer and 32-bit floatingpoint images and RGB color images.
- ImageTOOLSca (shareware, with a free trial period) - a FITS image viewer for Windows. Supports 16 and 32 bit integer FITS images.It can convert to or from other image formats such as TIFF, JPG, BMP, and Photoshop PSD, and can create AVI animations from a sequence of images.Also supports some image processingtasks such as bias subtraction and flatfielding.
- JS9 - next generation astronomical visualization from SAO for both desktop and web applications.
- KStars -KStars is free, open source, cross-platform (Linux, OSX, Windows) Astronomy Software. It provides an accurate graphical simulation of the night sky, from any location on Earth, at any date and time. KStars FITS Viewer tool supports grey scale and color (3D Cube) across all bit depths. It can display captured images from INDI cameras and video cameras.
- Libvips -a fully demand-driven, threaded image processing library with no image size limits and with good support for colour. Reads and writes FITS images, as well asTIFF, JPEG, PPM, PNG, and other file formats. Has interfaces to C, C++ and Python,and a command-line interface that can be called from shell scripts.
- MicroObservatoryImage 2.0 - astronomical image display program works with FITS and GIFimages on PCs and Macs. Can also perform mathematical image processingoperations on multiple images.
- PhAst - A flexible IDL tool to display and analyze FITS images. It can calibrate raw images, provide astrometric solutions, and do circular aperture photometry. PhAst allows the user to load, process, and blink any number of images. Requires either an IDL license, or installation of the (free) IDL Virtual Machine.
- QFitsView - An image viewer for 1-D, 2-D, and 3_D FITS images. It is written in C++ and uses the Qt widget library. Binary executables for Microsoft Windows, Linux, and Mac OSX, as well as the source code, are available.
- RSpec - A Windows software package with manyspectroscopic analysis features that can process 2D FITS images and 1D tables. Canremove background, rotate, extract and process profiles.30-day free trial version available.
- SkyCat - ESO tool combines image visualization and access to catalogs
- Tria -an advanced image processing suite for Windows platforms (only), including deconvolution, image registration, and noise filtering functions. SupportsFITS, TIFF, BMP, JPEG, PNG, and WMF image formats.
- xv (shareware) - interactive imagemanipulation program for X Window systems
- xINDI - xINDI is a suite of native astronomical software tools for MacOS X built around INDI standard. It consists of binary INDI distribution wrapped into INDI Server application, INDI Control Panel application and FITS Viewer. The viewer is based on CFITSIO library and supports all standard monochromatic and color FITS image formats. It shows both an image (zoomed and stretched automatically, but manual correction of black and white point is available) and the image metadata.
Image Format Converters - FITS to/from GIF, JPEG, etc
- Netpbm - a package of graphics programs and programming library. Thedocumentation is on-line.In particular, see the fitstopmnandpmntofits programs. To first order, the following command converts a jpeg image to a FITS image on most Linux systems:
- djpeg file.jpg | pnmtofits > file.fits
- ImageMagick - read, write, and manipulate images in over 68 formats
- pbmplus - image file format conversion package
- gimp - GNU Image Manipulation Package
- FITS2jpeg - a FITS to jpeg converter provided by Bill Cotton (NRAO). It needs the CFITSIO and libjpeg libraries and produces grayscale images.
- SAOImage ds9 - this FITS visualization application from SAO allows the image tobe saved as a jpeg, tiff, png, or ppm file on disk (use File->Saveas->Image...). This currently requires Ghostscript version 6.5 or higherin the path. From there one can go to gif format using xv. Anotheroption to is save the image as Postscript (File->Print...->File...) andthen use Ghostscript to convert to gif. (Provided gs was build witha corresponding gif driver included). The ds9 operations can bebuilt into a script using the XPA mechanism.
As an example, the following command will open the file 'name.fits', zoom it to fit the window,save it in JPEG format to the file 'filename.jpeg', and then exit
ds9 name.fits -zoom to fit -saveimage jpeg filename.jpeg -exit
Other output image formats, besides jpeg, are png, tiff, ppm, and mpeg.Optionally, one can add '-zscale' or '-geometry 800x800' options to customizethe output image. These options and more are described using 'ds9 --help'.
- MicroObservatoryImage 2.0- Image display and processing program can perform FITS to GIF conversion and create RGB color images or animated GIF files.
- fts2gif - a simple FITS to gif converter written by Michal Szymanski (Warsaw University Observatory). It requires the'raw2gif' application from the giflib-3.0 library (Linux and Solaris versions of raw2gifare included in the fts2gif tar file).
- ImageTOOLSca - (shareware, with a free trial period) converts 16 and 32 bitinteger FITS images to or from other formats such as TIFF, JPG, BMP, and Photoshop PSD, and can create AVI animations from a sequence of images.
- VOConvert- a tool for converting ASCII or FITS tables toVOTable format.This tool was developed as part of the Virtual ObservatoryIndia initiative.
Notes Regarding the Display of FITS Images
An application intended to render a FITS image for viewing by a user has significantly more responsibility than an application intended to handle other standard image formats (e.g., 'jpg' or 'gif' images). FITS data arrays contain elements which typically represent the values of a physical quantity at some coordinate location. Consequently they need not contain any pixel rendering information in the form of transfer functions, and there is no mechanism for color look-up tables. An application should provide this functionality, either statically using a more or less sophisticated algorithm, or interactively allowing a user various degrees of choice.(See also, ashort introduction to astronomical image processing).
Furthermore, the elements in a FITS data array may be integers or floating point numbers. The dynamic range of the data array values may exceed that of the display medium and the eye, and their distribution may be highly nonuniform. Logarithmic, square-root, and quadratic transfer functions along with histogram equalization techniques have proved helpful for rendering FITS data arrays. Some elements of the array may have values which indicate that their data are undefined or invalid; these should be rendered distinctly.
The data array in a FITS image must have a dimensionality between 1 and 999, the boundaries inclusive, indicated by the NAXIS keyword. The extent of any coordinate axis in a FITS data array may, however, consist of only a single element. Hence an algorithm designed to render two-dimensional images will be capable of displaying a three- or four-dimensional FITS array when one or two of the axes consist of a single pixel.
Three-dimensional data arrays (NAXIS=3 with multiple elements along each) are of special interest. Inspection of the World Coordinate System (WCS) keywords in an image with NAXIS = 3 or more may indicate that one of the axes is temporal. Writers of viewer applications should consider presenting such an image in a fashion akin to that used for an animated GIF. Even in the absence of WCS indication of a temporal axis this time-lapse display technique can be effective, and application writers should consider offering it for all three-dimensional arrays.
A FITS image with NAXIS=1 is a one-dimensional entity such as a spectrum or a time series. Writers of applications intended to handle these one-dimensional FITS images should consider presenting such an image as a graphical plot rather than as a two-dimensional picture with a single row.
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Astrophotography is closer to science than art, and there is no such thing as “getting it right in camera.” This means you cannot simply point the camera at the sky and snap away.
In astrophotography you cannot avoid post processing your images, so stacking and editing your images serves three main purposes:
- Reduce noise and deal with light gradients and vignetting.
- Improve signal to noise ratio.
- Reveal the faint details in the image.
Image stacking is the technique used to improve the signal to noise ratio, and it is the only noise reduction method that will boost the image details rather than smear them out.
In this article, we will discuss some of the most popular software available for astrophotography image stacking.
Note: Don’t miss the detailed video at the end of this article, It was created to help show you how to quickly start using some of the stacking software mentioned in this article.
Click here to skip to our Image Stacking Demo Video.
What Does Stacking Photos Mean?
The concept behind image stacking is simple, but to appreciate how it works, there are a couple of things we have to consider:
- A stack can be visualized as a pile of images all stacked one on top of the other;
- Each digital image is formed by a set of pixels, all having a certain value: dark pixels will have a lower value than the bright ones;
In the simplest form of image stacking, the pixels values for all images in the stack are averaged to produce a single image.
What is the purpose of stacking photos?
The result is a single image with improved signal to noise ratio, i.e., with better details and lower (random) digital noise and better details.
The scheme below illustrates the concept.
If the considered digital noise affects the pixel values randomly across the stack, then the result of averaging the stack is that the random component of the noise to the pixel value is significantly reduced.
ISO noise and Luminance noise and Chrominancenoise are examples of digital noises that are random.
The image below shows a real-life example from stacking 30 images from my Sony RX10 bridge camera taken at ISO 6400. As you can see, the original images showed a greater deal of noise (grain) than the stacked one.
The More Images You Stack, The Better
The more images you stack, the cleaner the resulting images are, as shown in the comparison below.
While Image stacking creates a cleaner image, it often softens the image: digital sharpening techniques are then used to recover sharp looking details.
Finally, bear in mind that the progression of image quality is not linear.
If stacking 4 images improves the image quality of 50% respect what you got by stacking only 2 images, to improve a further 50% the image quality from stacking 50 images, you may need to stack 300 images or more.
Image Stacking And Movement
If nothing moves between shots, like in the previous real life example, implementing image stacking is very simple: just group the images and average them to smooth out the noise.
With a moving subject, grouping and averaging the images will not only smooth out the noise, but also the subject itself.
This is the same principle for which long exposures of passing traffic and crowd result in a street image without cars nor people.
This effect is amplified with the number of images used, and the moving subject could simply disappear from the stacked image.
To resolve the issue, you have to align the images based on their content before stacking.
Due to image alignment, you may have to trim the edges of the stacked image to get rid of artifacts, but your target will not be lost.
Note that while in theory you can stack images of a static scene taken with the camera on a tripod, in reality, those images will probably differ at the pixel scale due to micro-movements. It is always beneficial to align the images before stacking.
How To Shoot For Exposure Stacking Your Images
Image stacking can be done with any camera and even camera phones and with images in both RAW and JPEG format.
Nonetheless, some things can be done to improve the final result:
- Lock the focus, so that the camera will not hunt for it between images. This will also help to keep the focus consistent through the shooting sequence.
- Keep the same settings, in particular shutter speed, aperture, and focal length: you don’t want to change the camera field of view during the sequence, nor the brightness of the images or the depth of field.
- If you are shooting on a tripod, disable image stabilization. If you want to shoot handheld, do so only for short sequences at very high shutter speed.
Image Stacking In Astrophotography
Related:Astrophotography Software & Tools Resource List
As said previously, image stacking is a standard technique implemented in any astrophotography editing workflow for,
- A star field from a fixed tripod.
- A deep sky object from a tracking mount.
- The Moon handheld.
- A starry landscape from a fixed tripod or tracking mount.
Every astronomy image will benefit from image stacking.
List Of Photo Stacking Software For Astrophotography
Here is a list of software used in astrophotography for image stacking.
Adobe Photoshop
Complete Image Editor | Commercial – Subscription Plan Photography Bundle $9.99 / Month | Mac OS X, Windows
Pro
- Versatile
- Available for Mac and Windows
- In bundle with Adobe Lightroom CC, Bridge, Camera Raw, and web space
- Many action packs and plugins available for astrophotography
Cons
- Subscription Plan only
- Can’t be used to calibrate light frames
- Stacking capabilities are somehow limited
If you are interested in photography, chances are you know Adobe Photoshop is the standard in the industry and does not need introductions.
With Adobe implementing a subscription plan for their applications, if you are using Lightroom CC for your everyday photography, your plan subscription will also include Photoshop CC and Bridge CC.
And for astrophotography, Photoshop is what you need. Lightroom cannot stack your images nor perform the histogram stretching, two crucial steps in the editing workflow for astrophotography.
In this article, we have already covered in detail how to stack astrophotography images with Photoshop.
Sequator
Deep Sky And Starry Landscape Stacker | Freeware | Windows
Pro
- Free
- Easy to use
- Fast
- Suitable for both Starry Landscapes and Deep Sky images
- Can create Star Trails
Cons
- Windows only
- Limited set of options
- Not suitable for Planetary astrophotography
Sequator is an easy-to-use and intuitive astrophotography software for stacking both starry landscape and deep-sky images. It can also be used to create star trails.
While not as advanced as other stackers, it nonetheless allows you to calibrate your light frames with dark and flat calibration frames. It also allows you to remove light pollution, reduce noise, and perform other simple tasks on the stacked image.
Starry Landscape Stacker
Starry Landscape Stacker | Commercial, $39.99 | Mac OS X
Pro
- Fast
- Easy to use
Cons
- Mac Os X only
- Does not read RAW files
If you are into starry landscapes and you are a Mac user, Starry Landscape Stacker is a must-have.
Easy to use, it allows you to stack and align the sky and the foreground independently by letting you easily mask the sky.
Unfortunately, the software lacks the support for RAW formats, thus forcing you to convert your RAW images in the more heavy TIFF format.
Aside from that, it works very fast and the final image is of good quality. You can also save the sky only, which is useful to further edit the shot in Photoshop or similar editors.
Starry Sky Stacker
Deep Sky Stacker | Commercial, $24.99 | Mac OS X
Pro
- Fast
- Easy to use
Cons
- Mac Os X only
- Does not read RAW files
- Basic
Starry Sky Stacker is Starry Landscape Stacker brother and it has been created to stack deep sky astrophotography images.
As Starry Landscape Stacker, Starry Sky Stacker is very easy to use and intuitive, although very basic.
If you are a casual star shooter and a Mac user, this could be a good choice for you.
Deep Sky Stacker
Deep Sky Stacker | Freeware | Windows
Pro
- Free
- Easy to use
- Fast
- Full light frames calibration
- Features Comet stack modes
- Can Drizzle
- Many advanced stack options and methods available
Cons
- Windows only
- Post-processing is quite limited
- Not suitable for Starry Landscapes nor for Planetary astrophotography
Deep Sky Stacker, better known as DSS, is arguably one of the most widely used software to calibrate and stack astrophotography images.
With DSS, you can fully calibrate your images with Darks, Flats, Dark Flats, and Bias calibration frames for the best results possible. Light frames are analyzed and scored by quality so that you can decide which percentage of best images you can stack (Best 75% by default).
A very interesting feature is that with DSS, you can easily combine images taken during different imaging sessions, to produce images of higher quality.
Autostakkert!
Planetary Stacker | Freeware | Windows
Pro
- Free
- Easy to use
- Suitable for Planetary, Lunar and Solar images
- Stack full planetary disk and lunar surface close-ups
Cons
- Interface a bit confused
- It does not offer wavelet sharpening
- Windows only
Autostakkert!, also known as AS!, is a very popular free software among the solar system astrophotographers. With AS! it is easy to stack both images showing the full Planetary (or Lunar or Solar) disc and images showing lunar surface close-ups.
The interface is a bit confusing, particularly in the beginning, but it is easy to navigate through the different steps for the stacking.
Unfortunately, AS! does not offer wavelet sharpening, which is a widely used technique in planetary and lunar astrophotography. For this, you can load your stacked image in Registax, another freeware software for Windows only that, sadly, is now “abandoned-ware.”
Lynkeos
Planetary Stacker | Freeware | Mac OS X
Pro
- Free
- Has deconvolution and wavelet sharpening
- It is probably the only freeware planetary stacker for Mac OS X
Cons
- Not very intuitive
- Somewhat slower than Autostakkert!
Lynkeos is perhaps the only freeware planetary stacker software for Mac OS X, sparing you from turning to Windows for using Autostakkert!.
The interface is quite intuitive to navigate, but not when it comes to performing the different tasks.
On the other hand, it offers a deconvolution method and wavelet sharpening, a must-have for a planetary stacker. Definitely worth having a look at it if you are a Mac user.
SiriL
Deep Sky Astrophotography Editor | Freeware | Mac OS X, Windows, Linux
Pro
- Free
- Cross-Platform
- Active development
Cons
- A bit convoluted and not as intuitive as other stackers
SiriL is a freeware, cross-platform, astrophotography package that will let you calibrate, stack, and develop deep sky astrophotography images.
While not as easy and intuitive as Sequator or DSS, it offers a lot of options and produces good results. There is an active community, and it is under constant development.
Astro Pixel Processor
Deep Sky Astrophotography Editor | Commercial $60/Yr Renter License Or $150 Owner License | Mac OS X, Windows, Linux
Pro
- Full-grown astrophotography package
- Fairly easy to use
- Mosaics are created with ease and are of great quality
- Active and constant development
- Cross-Platform
- 30-days Trial period
- Affordable yearly subscription
Cons
- Only for deep sky astrophotography
- No Comet stacking mode
Astronomical Image Processing
With Astro Pixel Processor (APP), you step in the realm of full-grown astrophotography packages, with many advanced options and methods to calibrate, stack, and post-process your deep-sky images.
Compared to PixInsight (PI), the software benchmark for the category, APP is cheaper and way easier to use, which makes it one of the best PI alternatives.
If you decide to buy it, you can choose between the renter’s license for $60/yr, to always get the latest version of APP, or the owner’s license for $150, but you will have to purchase the license again for major update releases.
PixInsight
Astrophotography Editor | Commercial – €230+VAT | Mac OS X, Windows, Linux
Pro
- It has all you need for astrophotography
- 45 days trial period
- A lot of tutorials and information available
Cons
- Expensive and without subscription plan
- Extremely steep learning curve
- Long and convoluted process
- Needs a powerful computer
When it comes to astrophotography, PixInsight is the software of reference against which all others are measured. It offers everything you may possibly need to produce pro graded images, and it is objectively the best software in the field.
But user experience can be frustrating, as the learning curve is very steep, the editing is long and convoluted, and your computer must be quite recent and powerful to make it run smoothly.
The €230 + VAT price tag is also quite steep: sure it is worth every penny, but this makes PI be even more the software of choice for professional and keen amateur astrophotographers.
A Comprehensive Demo About Image Stacking
Astronomy Image Processing Software For Macbook Pro
In this video, I show you how easy it is to wet our feet with image stacking.
This is particularly true if you use Starry Landscape Stacker, Sequator, Deep Sky Stacker and Autostakkert!, as I showed in the video below.
Image Processing Software Wikipedia
Conclusion
Image stacking is one of the crucial steps in the astrophotography editing workflow.
You’ll need the appropriate stacker for each type of astrophotography: starry landscapes, star trails, or deep-sky and planetary images.
In this article, we have covered the most popular astrophotography stackers available on the market, both freeware and commercial.
And while Windows users have the more extensive choice, some notable stackers are available for Mac and even Linux users.