Astrophotography Software - 'The Essential Guide'
There are a number of different types of software that have been developed specifically for Astrophotography, which will be beneficial to both the beginner and expert astrophotographer alike.
This specialist software is additional to that provided by manufacturers of DSLR cameras, which often falls short in providing the necessary functions and facilities required in astrophotography.
A number of the better software packages often provide capabilities in more than one area and are able to be used by both Astronomical CCDs (ACCD) and Digital Single Lens Reflex (DSLR) cameras, e.g. Maxim DL or Nebulosity.
However many astrophotographers use more than one software package to handle their astrophotography workflow process, e.g. Maxim DL for camera control, image acquisition and image calibration; and Photoshop and plugins for image processing.
In addition the majority of Windows software is not Mac Compatible and vice versa.
However all the Windows software can be run on a Mac if you use virtual machine software such as Parallels Desktop or VMware Fusion.
A detailed guide to Astrophotography Software can be found at:
www.artdeciel.com/software.aspx
The following is a list of the most commonly used types of astrophotography specific software:
Auto Guiding Software
For long-exposure deep-sky astrophotography, guiding during the exposure can be very useful in producing higher quality images.
By manually or automatically following a star by making corrections in right ascension and declination higher tracking accuracy is obtained.
Auto guiding involves using a separate CCD or Webcam to monitor a stars position and then send corrections to the telescope's mounting to guide or follow the star with high accuracy to compensate for inaccuracies in the mount's tracking.
CCD cameras and webcams can be also be used as autoguiders, but software, such as GuideDog and PHD, is required to run on a computer that interfaces between the autoguider and mount.
A number of the better ACCDs such as those manufactured by SBIG have a separate Guide Chip to perform the auto-guiding process in addition to the larger imaging Chip.
Camera Control Software
With camera control software, you can use your computer to control all of the functions and settings of your ACCD or DSLR, such as setting the exposure length and opening the shutter.
If your ACCD is fitted with a Filter wheel then this software will also control the changing of filters in an LRGB sequence of exposures.
Several of best the Camera Control Software, e.g. Maxim DL can also handle other tasks such as focusing, guiding, image acquisition, image calibration and image processing.
There are also a number of software packages which are particularly suited to webcams, e.g. Craterlet and K3CCD Tools.
Focusing Software
A number of software programs exist which can be used to assist in the focusing of astronomical objects in an ACCD or DSLR.
The latest generation DSLR cameras allow focusing through the camera manufacturer's software. This can be done by manual focusing and visual inspection of the Live-view image on the computer, or by autofocus if the camera is shooting through an autofocus lens.
For previous generation cameras without Live-View, an image has to be downloaded to the computer and then visually examined for focus accuracy.
However the most effective method of focusing particularly suited to ACCDs requires the use of auto focuser hardware such as RoboFocus or Optec TCF-S focuser which are attached to the telescope. These are used in conjunction with assisted focus software such as that found in Maxim DL or by separate programs like FocusMax.
Image Acquisition Software
Deep Sky Astrophotography requires a number of shorter sub-exposures for each of the LRGB filters.
This can be done manually, but it is very tedious.
For example, faint deep-sky objects may require several hours worth of 5 minute sub-exposures that are later stacked or combined in subsequent image processing.
Software such as Images Plus or Maxim DL can automate this process.
You simply specify in the software that you want the DSLR camera or colour ACCD to shoot, say, 30 exposures of 5 minutes with a 10 seconds between frames (to give the system time to download each image).
When using a mono ACCD you will need to specify the number of exposures, their length and delay for each of the LRGB filters.
Image Calibration Software
In Astrophotography it is necessary to calibrate the original raw images.
Calibration means removing unwanted fixed signals (such as thermal current and bias), and correction for signal modifications (such as vignetting) so that the raw image accurately represents the intensity of light incident on the sensor during the exposure.
To calibrate your original raw astronomical images, you will require some type of special astronomical image processing software, such as Images Plus, Maxim DL, MaxDSLR, AIP4Win (Astronomical Image Processing), AstroArt, IRIS, Deepsky Stacker or Regim.
Stacking is the name of the process used to combine many individual short exposures into a master image by any of several mathematical processes such as averaging, or addition.
The term originates in the days of film astrophotography where images were literally stacked on top of one another to improve contrast and colour.
You will also need to align your images so that the stars in them line up perfectly.
Whatever software you use for image calibration will almost certainly also do aligning and image stacking.
It is possible to align and stack images in Adobe Photoshop, but for more than a couple of frames, the process is extremely tedious and not as accurate as with a dedicated astronomical image processing program.
Image Processing (Correction & Enhancement) Software
Once your images are calibrated, aligned and stacked, you will want to correct for things such as colour balance, and increase the contrast to make faint details more visible.
You will probably also want to apply some type of noise reduction, and you may want to apply more sophisticated enhancement techniques.
These processes can be done in the previously mentioned astronomical image processing programs such as Images Plus, Maxim DL, AIP (Astronomical Image Processing), AstroArt, and IRIS.
However, at this stage of image processing, many astrophotographers prefer to switch to a general image processing program such as Photoshop.
Planetarium Software
Planetarium programs and atlases let you find out what is up in the sky, and plan your observing and astrophotography sessions.
They can also be used to control your telescope and give you FOV indicators for a given CCD/Telescope combination, as well as help you find a suitable guide star.
Two of the better planetarium programs are TheSky6 and Starry Night Pro.
A number of these packages are specific Lunar Atlases, e.g. Virtual Moon Atlas and Lunar Phase Pro.
A number of programs in this category are space travel simulators. In this category of software are programs like Celestia and Seeker.
Photoshop Plug-ins
These filters and actions work inside of Photoshop and perform specialty functions for astronomy, such as gradient and noise reduction.
Used correctly these can give you an order of magnitude improvement in your images.
Examples of this type of software are Noel Carboni's Astronomy tools and Russell Croman's Gradient XTerminator.
Photo Extras
These programs perform useful image functions like allowing you to open FITS format files, perform noise reduction, and create thumbnails for indexing and archiving.
Examples of this type of software are FastStone Viewer, Thumbnails Plus and Easy Thumbnails.
Tutorial Software
There a number of Tutorials in book and video format teach you how to do astrophotography, and use programs such as Images Plus for image calibration and Photoshop for image correction and enhancement.
One recommended book is the New Astro ‘Zone System for Astro Imaging’, which uses Photoshop to manipulate FITS, JPEG and TIF format images
Utility Software
Finally there is Utility software which provide a variety of useful functions often required by the astrophotography, e.g. Polar Alignment, Periodic Error Correction (PEC) of Mounts and Session Planning.
Examples of this type of software include CCD Navigator (image session planning), PoleAlignMax (polar alignment), PemPro (PEC).
Recommended Software
Here are my favourites in each of the various categories of software:
AutoGuiding: PHD (PC), Maxim DL (PC);
Camera Control: K3CCD Tools (webcam, PC), Maxim DL (PC), Nebulosity (Mac);
Focusing: FocusMax (PC);
Image Acquisition: AstroIIDC (Mac), Craterlet (Webcam, PC & Mac), K3CCD Tools (webcam, PC), Maxim DL (PC), Nebulosity (PC & Mac);
Image Calibration: AstroStack (Mac), CCDStack (PC), Maxim DL (PC), RegiStax (webcam, PC), AstroIIDC (webcam, Mac);
Image Correction and Enhancement: Photoshop (PC & Mac);
Photo Extras: Faststone (PC); Easy Thumbnails (PC), Picassa (PC & Mac);
Photoshop Plugins: Astronomy Tools (PC & Mac), Fits Liberator (PC & Mac), FitsPlug (PC), Gradient XTerminator (PC & Mac);
Planetarium: Cartes du Ciel (PC), DeepSky (PC), The Sky6 (PC), TheSky Serious (PC & Mac);
Utility: AstroPlanner (PC & Mac), CCD Navigator (PC).
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