The command line User's Manual is available here
Registering and Stacking Tab
Create a Star Mask
The Picture List
Picture Preview (Stars and Comet editing)
RAW and FITS DDP Settings
The purpose of this short manual is to explain the features and principles of DeepSkyStacker.
The user interface of DeepSkyStacker is quite simple and intuitive and all the main features and commands are readily available.
To change the current tab you can click anywhere in the tab.
You are just out of a busy night and you just have downloaded all your pictures (lights, darks, offsets and flats) to your PC.
The first step is to add all the pictures (accordingly to their type) to the list.
To do this you use the commands of the left area:
- add picture files
- add dark files
- add flat files
- add offset/bias files
- add dark flat files
Then you just launch the registering process, you check the "Stack after registering" box after entering the percentage of pictures that you wish to keep for the stacking process after the registering process.
If you are using raw files (which is highly
recommended), you just check the Raw DDP settings and you start the registering
You can now go to sleep knowing that after a good night you will view the first results in the processing tab.
Note that even if your PC crashes after the stacking process, the result is automatically saved in a special file: AutoSave.tif.
Registering and Stacking Tab
The Registering and Stacking Tab contains all the commands and features pertaining to the registering and stacking processes.
From this tab, you can add frame of each type (light, dark, flat and offset/bias) to the list, save and restore File Lists, preview images and start the registering or stacking process
To the top and the right a slider may be use
to change the gamma of the previewed image which may be useful to view faint
The "Compute offsets" feature may be used to compute the offsets and rotation
angles between the pictures without starting the stacking process. Once computed
the dX, dY and angle columns of the pictures list are populated with the
computed offsets and rotation angles.
Note: it is not necessary to compute the offsets manually prior to the stacking process since the offsets and rotation angles are automatically computed just before the stacking process anyway.
The "Check above a threshold..." may be used to check all the pictures for which the score is greater than or equal to the given threshold value.
Before the stacking process a screen
recapitulates the different steps.
From this dialog you can also change the stacking methods for each type of picture by clicking directly on the link or on the "Stacking Parameters" button.
A new dialog is then opened, from which you can modify the folder into which are created the temporary files needed by the stacking process and all the settings controlling the stacking process.
The first tab is used to set the stacking mode
among which the possibility to use a
This is also where you can choose the Drizzle option when stacking.
The other light, dark, flat and bias tabs are used to modify the stacking method for each type of frame, and to activate the background calibration option for the light frames or the automatic detection and removal of hot pixels and bad columns detection and removal for the dark frames.
You can choose Bilinear, Bisquared or Bicubic transformation or you can DeepSkyStacker select the best transformation based on the number of available stars.
This tab is used to control the creation
of intermediate files.
The goal is to detect and clean remaining hot or cold pixels after calibration.
Checking these options may seriously alter the resulting image so use them with caution.
Two parameters are needed to define the behavior of the cosmetic cleaning.
The first parameter is the size of the filter used to detect and fix the hot/cold pixels. The larger the filter, the longer the processing time and the smoother the resulting image.
The second parameter is the
threshold under which no correction is done (the pixel value remain the
The last option may be
checked to create an image showing the cleaned pixels for each light frame.
case the Comet tab is used to select the comet stacking mode between the 3
After the stacking process, the resulting image is saved in the AutoSave.tif file which is created in the folder of the reference light frame..
If an Autosave.tif file already exists in the folder, an Autosave001.tif (002, 003, ...) is created.
The Batch Stacking dialog is used to create resulting images from more than one stack.
For example it may be used
to create the resulting images from the red, green, blue and luminance
images without the need to load each list then start manually the stacking
process for each one.
At the end of the stacking process, the output file name replaces the list name for each processed file list.
The processing tab contains the commands and features pertaining to post processing.
I would like to remind here that
DeepSkyStacker only allows simple processing treatments of the resulting
picture in order to quickly view the result of the stacking process.
The processing tab contains a
preview of the RGB histogram and three sub tabs which are used to adjust the
Adjusting the RGB Levels
The RGB levels adjustments are
The simplest way to understand how the different
parameters are working is to change them and look at the result on the
Adjusting the Luminance Curve
The luminance curve is
controlled by 6 parameters.
The simplest way to understand how the different
parameters are working is to change them and look at the resulting the luminance
adjustment curve (black curve) on the histogram.
Adjusting the Saturation
The saturation level adjustment is just a percentage of increasing or decreasing the saturation level.
The RGB histogram is used to
visualize for each channel (R, G and B) the red, green and blue pixels
distribution in the picture.
Saving/Loading adjustment parameters
Undo/Redo adjustment parameters
On the bottom of each tab a set of buttons is available:
- to apply the last modifications to the picture
- to undo the last applied modifications
- to redo the last undone modifications
- to reset all the values
- to access a dialog used to save/load a named set of parameters.
Loading a picture
DeepSkyStacker can load DSImage images (created only after the stacking process), TIFF images (8, 16 and 32 bit, gray levels or RGB) or FITS images (8, 16, 32 and 64 bit, gray levels or RGB).
At the end of the stacking process the AutoSave.tif picture is automatically loaded.
Saving the resulting picture
DeepSkyStacker can save the
resulting image as 16 or 32 bit TIFF or FITS files using two methods::
For more information about the saving methods you can read the faq.
Create a Star Mask
Using a Star Mask is often very useful during post-processing to use different processing techniques for the stars and for the rest of the image.
The Create a Star Mask feature may be used to create a variety of star masks that can be used later in any software you are using to post process (Photoshop, PixInsight, ...).
DeepSkyStacker is only creating star mask files. It is not using them in any way.
You can view this feature as a tool intended to provide quickly and simply a star mask file based on real star detection.
What is a star mask?
Star Mask Creation
Then just click on the Create Star Mask... menu on the right and the dialog on the right will open.
From there you can change the shape of the stars in the mask, the star detection threshold and a few other parameters.
Once you are done, just click on the OK button and you will be asked to select a file (either a TIFF or a FITS file) in which the star mask will be saved.
The saved file is always a grayscale 16 bit image. It is not automatically loaded by DeepSkyStacker.
The star mask is always created from the image as you see it in DeepSkyStacker which means with the current adjustments applied.
The picture list, common to Registering and Stacking processes contains all the pictures used by the registering and stacking processes.
- Light frames
- Dark frames
- Flat frames
- bias/offsets frames
Only the checked pictures are used by the registering and stacking processes.
The list contains the following columns:
|Checkbox||checked if the picture should be used|
|Path||Path to the picture file|
|File||Name of the picture file|
|Score||Picture score computed by the
registering process or
N/A for dark, flat and bias/offsets frames.
When you have selected a frame as the reference frame using the context menu, the score is preceded by (*).
|dX||X offset (in pixels) computed for the stacking process|
|dY||Y offset (in pixels) computed for the stacking process|
|Angle||Rotation angle (in °) computed for the stacking process|
|Date/Time||Date and Time of the file|
|Size||Size of the picture in pixel (Width x Height)|
|CFA||Yes if the picture is resulting from a Color Filter Array (CFA) which is the case of all the RAW pictures using a Bayer matrix.|
|Depth||Type (gray levels or RGB) and number of bits per channel of the picture.|
|Infos||Extra information about the picture (RAW with DSLR information, TIFF or Other)|
|ISO Speed||ISO Speed of the picture|
|Exposure||Exposure time of the picture|
|FWHM||FWHM: Full Width Half Maximum
value. (in pixel)
This is the average for all the detected stars
When a comet position is set a +(C) is appended to the number of stars
|Sky Background||Sky background value for registered image in %|
You can sort the list on any column by clicking
on the column header (and by clicking again to reverse the sort order).
You can change the columns order and each column width. Everything is saved after each use of DeepSkyStacker. The column widths order will be reloaded the next time DeepSkyStacker is used.
You can preview a picture from the list by selecting it.
If the selected picture is a RAW file, the RAW DDP settings will be used to decode the RAW file before previewing it.
You can select multiple files in the list.
The properties dialog may be used to change the
picture type, and temporarily (only for the current session) the ISO speed
and exposure time of one or more pictures.
The picture preview is used to quickly view a picture from the picture list (Registering and Stacking Tabs) or to view the picture being processed (Processing Tab).
You can zoom in and zoom out by pointing the mouse and using the wheel. This is the only way to pan and to zoom.
Star and Comet editing
When a light frame is selected in the registering and
stacking tab it is possible:
You can select one of the above modes using the toolbar in the bottom right corner of the image.
The last item of the toolbar is used to save the changes.
When used from the processing tab, the picture preview may be used to select a part of the image by drawing a rectangle directly on the picture.
This rectangle is used on one hand to apply
the adjustments only to this rectangle and on the other hand, optionally, to
save only a part of the image.
If no rectangle is defined the adjustments are applied to the full image.
In all the cases, when the image is saved to disk the adjustments are applied to the full image.
Raw and FITS DDP settings
The Raw DDP settings dialog gives access to all the parameters used while developing a RAW file to transform it into a picture.
The Color Adjustment is applied
after the White Balance adjustments for Daylight White Balance (the
default) or Camara White Balance (if selected). The white
balance adjustment values are extracted from the RAW files by LibRaw Copyright © 2008-2019
LibRaw LLC. LibRaw is based upon the original DCRaw decoder for
RAW files written by Dave Coffin. Use Auto White Balance is no
More information about the interpolation mode and the specific behavior of the Bayer matrix optimization, is available in the technical details.
All the other settings are only used with 16 bit B&W FITS files created by a DSLR
or a color CCD camera.
The parameters are:
More information about the interpolation mode and the specific behavior of the Bayer matrix optimization is available in the technical details.