Advanced Topics

Command Line Arguments

SharpCap can be launched with a selection of command line arguments to customize its behaviour and deal with unusual situations:


Run SharpCap in a language other than the default Windows language. Specify the language code for a language that SharpCap supports, for example ‘fr’, ‘zh-CN’, ‘de’, ‘jp’.

Example :

/language fr


Open the specified camera when starting SharpCap. If the camera name contains spaces, enclose the camera name in double quotes.


/camera "ASCOM Camera Driver for DSLR"


Force SharpCap to use software rendering rather than an accelerated graphics card driver for certain parts of the UI. Use this option if you are running SharpCap via remote access software and parts of the SharpCap window are blank.


If this option is specified then SharpCap will not enable high DPI awareness mode. If you use SharpCap on a high DPI monitor and sizes of windows, text or other items is incorrect, it may be worth trying this option. Text may appear blurry on high DPI monitors with this option, but correct sizes of items should be restored.


Run the specified python script file after SharpCap finishes loading. See Scripting for more details.


/runscript d:\files\


Run the specified SharpCap sequence file after SharpCap finishes loading. See the SharpCap Sequence Editor for more details. Note that this needs to be an SCS file from the sequence editor, not an SSP or SSV file from the Deep Sky or Solar System Sequence Planners.


/runsequence d:\files\allskycamera.scs


Create a crash dump minidump file on the desktop if SharpCap encounters a fatal error. Use this option if SharpCap crashes and does not offer the opportunity to submit a bug report.

The minidump file will be saved on the desktop and called SharpCap.dmp. Please send minidump files to technical support via the forums.

Note that this option is not supported by the 64-bit version of SharpCap.


Run SharpCap with an alternative configuration. Specify a configuration instance number in the range 2-9.


/instance 2

When you first use an instance number, all your SharpCap settings will be copied from the default configuration. From that point onwards, settings changes made in the default instance will not affect the new instance (and settings changes in the new instance will not affect the default instance).

This approach allows you to set up two or more configurations for SharpCap, perhaps if you have multiple sets of imaging equipment attached to the same computer.

Note that the following items are shared between instances :

·         SharpCap Pro licenses

·         Capture Profiles, including the ‘auto save’ profiles used to restore previous camera settings automatically

·         Auto-saved sequence editor and sequence planner configuration


Use this option to start translating SharpCap to a new language.

See this thread on the forums for details of how to create a new translation of SharpCap. Please consider contributing your translation to the official version of SharpCap so that it can benefit other SharpCap users.


Reset all SharpCap settings during startup. This may help if SharpCap crashes on startup, particularly if it begins doing this after one or more settings have been adjusted.


Provides debugging information about the very early phases of SharpCap startup. If SharpCap crashes before showing the main window then running with this option may produce extra information allowing you to report the issue on the forums.


Keyboard and other Shortcuts

The following keyboard shortcuts can be used to control SharpCap

<CTRL> while opening SharpCap

Do not open a camera at start-up, do not run start-up scripts or sequences

<SHIFT> while opening SharpCap

Show SharpCap log immediately

<CTRL> while opening a camera

Do not load any saved default capture profile for the camera, also do not restore previously used camera settings

<SHIFT> while adjusting histogram stretch levels

Move the histogram stretch level 10 times more slowly than mouse movement for fine control

<CTRL> when using the Auto Stretch buttons

Apply a stronger than normal auto stretch

<SHIFT> when using the Auto Stretch buttons

Apply a weaker than normal auto stretch

<CTRL> + Mouse Wheel over image

Zoom in/out

Mouse Wheel over image

Scroll up/down

<SHIFT> + Mouse Wheel over Image

Scroll left/right


Zoom In


Zoom Out

<CTRL> + 1

Zoom to 100%

<CTRL> + 0

Set Zoom to Auto (fit image to available space)


Reduce Exposure


Increase Exposure


Reduce Gain


Increase Gain


Reduce Black Level/Offset/Brightness


Increase Black Level/Offset/Brightness


Move focuser in negative direction


Move focuser in positive direction


Adjust Exposure/Gain shift by -1 for shorter exposures, higher gain


Adjust Exposure/Gain shift by +1 for longer exposures, lower gain


Show Scripting Console


Toggle full screen mode


Toggle night mode


Toggle two monitor mode


Start Capture


Quick Capture (most recently used length)

<ALT>+T or <ESCAPE> while Capturing

Stop Capture


Snapshot single frame


Activate Live Stacking


Exit SharpCap


Move mount left


Move mount right


Move mount up


Move mount down

<ESCAPE> (while capturing)

Stop Capture


Connect or disconnect all hardware


Show Histogram


Enable Live Stacking


Run an automatic refocus


Activate Deep Sky Image Annotation

<CTRL>+<SHIFT>+F1 to F12

Change to filters 1 to 12


Note that the mount movement keys are equivalent to the left/right/up/down direction buttons in the Mount Control – the mount will continue moving while the key is held down.




SharpCap has a scripting language built in that allows simple programs to be written that can perform just about any action that can be performed when controlling SharpCap with the keyboard and mouse.  The scripting language is based on a language called IronPython which is a Microsoft port of the Python Programming Language to the .NET framework.

Note that Python Scripting is a SharpCap Profeature.

The Scripting Console

The Scripting console can be shown by selecting Show Console from the scripting menu.  The scripting console is an Integrated Development Environment (IDE).  This allows for the creation, execution and debugging of code using the IronPython programming language and its integration into SharpCap.


Typing help() and <ENTER>  into the IronPython Console window gives the following basic help output:


Some examples are displayed.  One of these is code to list the cameras available to SharpCap.

#List the cameras available
print SharpCap.Cameras


Lines beginning with # are comment lines, meaning they are ignored by the computer.

Code can be typed directly into the console or pasted into the IronPython Pad in the lower part of the console window. If code is typed into the upper part of the window, it will be run when the <Enter> key is pressed.  Longer sections of code should be typed into the lower editor area where they are not run until the ‘Run’ button is pressed.

Controlling SharpCap is handled using the SharpCap object which is automatically loaded into each script session. Some simple commands would be...

SharpCap.SelectedCamera = None # Close the camera that is currently active

SharpCap.SelectedCamera = SharpCap.Cameras[0] # Open the first camera in the Cameras menu and start previewing it


Once a camera is running, adjust its properties like this

SharpCap.SelectedCamera.Controls.Exposure.Value = 1000 # Set the exposure to 1000ms (1s)


 In the IronPython Pad, type in the code print SharpCap.Cameras and press the Run button.


The following output appears in the IronPython Console.


Click the floppy disk icon and save the file as for use in the Run Script menu item below.

Exploring the API

The editor automatically shows the possible methods and properties for an object upon typing the '.' – this helps explore the available API.

In the IronPython Console, type the following two lines (the case of the text matters and the ‘.’ matters):

import System

from System.


As soon as the ‘.’ is typed, a list appears allowing selection.  This trick can be applied to many parts of the SharpCap API to allow discovery of the methods available and what parameters they require.


You can also explore the methods and properties available on any object by using the help command - for instance




Note: The API available for use in scripts in SharpCap is subject to change in future versions. While every effort will be made to retain compatibility with existing scripts, this is not always possible – sometimes scripts may need modification to continue working correctly in an updated version of SharpCap.

Run a Script

The Run Script menu item opens a File Explorer window to allow selection of a previously created Python script.

Scripts (programs) can also be created from within Windows using any text editor.  The scripts must be saved with a .py extension.

From the Menu select Scripting > Run Script.


Browse to the file and click the Open button.  The script should execute.


1.       From the Menu select Scripting > Show Console.

2.       Drag the Iron Python Console to one side using the mouse.

3.       From the Menu select Scripting > Run Script.

4.       Navigate to the file, created in the previous section, and select it.

5.       The script executes and the result (the available cameras) is shown in the IronPython Console.


The above example has no practical use but serves to demonstrate how to use SharpCap functionality.

Note: A number of methods available on the SharpCap scripting API return a Task object – these methods run asynchronously (i.e. they start a process and return before the process has finished). Often, there will be an alternative method that does not involve the asynchronous behaviour, and that alternative should be preferred when writing scripts. For example (from the ‘help’ for SharpCap.SelectedCamera):

|  RunCapture(...)

|      RunCapture(self: Camera)

|  RunCaptureAsync(...)

|      RunCaptureAsync(self: Camera, cancellationToken: CancellationToken) -> Task

Where possible, use the non-async version of the method – for instance RunCapture rather than RunCaptureAsync. If you need to use an Async method from Python scripting, you can use .Wait() or .Result to wait for completion or access the result (return value) of the asynchronous method.

Scripting Tutorial

Create a Script

This section shows how to:

·         Create a simple script using the IronPython Console.

·         Save the script.

·         Run the script from within the console.

·         Run the saved script directly from the Run Script menu option.


Upon selecting Show Console, an Integrated Development Environment (IDE) is displayed.  This allows for the creation, execution and debugging of code using the IronPython programming language.


The code below will capture a single PNG image and save it to a file.  The destination d:\capture.png will need to be changed to somewhere convenient on the computer being used.



Complete the following steps to test the scripting functionality:

1.       Start SharpCap and from the Menu select Cameras > Test Camera 1 (Deep Sky)


The M42 image should be shown in the Capture Display Area.


2.       In the Camera Control Panel, change the Output Format to be PNG files…


3.       From the Menu select Scripting > Show Console.


The IronPython Console will open.

4.       Copy the following code:


and paste it with CTRL  (or type directly) into the IronPython Pad (bottom part of the IronPython Console).  Edit the destination (underlined in red) to be something appropriate on the PC in use.


5.       Press the Run icon (or F5).


6.       Check the destination which, all being well, should now contain 2 new files called capture.png and capture.png.CameraSettings.txt.


7.       Edit the code to change the capture file name to be capture2.png.


8.       Click on the floppy disk icon and a file explorer window opens. 


Save the file as (the .py extension is important).

9.       Close the IronPython Console.

[Note: Of course, the point of scripting is to automate the use of SharpCap, and all of the above steps could be automated by a more complex script – for example:

SharpCap.SelectedCamera = SharpCap.Cameras.Find( lambda x:x.DeviceName == "Test Camera 1 (Deep Sky)")

SharpCap.SelectedCamera.Controls.OutputFormat.Value = "PNG Files (*.png)"



SharpCap Scripting Object Model Reference

The major objects available to control the application are:


The main application object, all other objects are accessed via this object.


A collection of available cameras (as shown in the Cameras menu) 


The camera that is currently open (or 'None' if no camera open)


The controls available on the currently open camera. Many common controls can be access directly, but others will need a check of each item in the array to find the control needed.  


A collection of (ASCOM) focusers detected by SharpCap. SharpCap.Focusers.SelectedFocuser can be used to connect to a specific focuser and then access it via the SelectedCamera.Controls collection.

SharpCap.Mounts, SharpCap.Wheels, SharpCap.Rotators, SharpCap.SwitchDevices

Collections of ASCOM mounts, filter wheels, rotators and switch devices, work in the same way as Focusers.


A collection of frame transforms that can be applied to the preview window by setting the SharpCap.Transforms.SelectedTransform property (buggy at the moment)


The main application window of SharpCap. Take care changing properties or calling methods on this as it may break things.  


Collection of reticule overlays that may be selected for drawing on the screen (like the transforms, also currently buggy)


Selected application settings, alter with care and call 'Save()' after any changes to make them take effect


Access the sequencer, allowing sequences to be run from Python scripts


Access the display stretch settings


Access key information and actions related to live stacking


Adjust the display zoom level




In general, the most used objects will be SharpCap.SelectCamera and SharpCap.SelectCamera.Controls.

The Camera Object

The most important methods and properties on the SelectedCamera object are (informational properties will work on other non-selected cameras):

 CanCapture, CanStillCapture

Indicate whether the camera can capture video and still frames, respectively


Can the camera pause a video capture without stopping it?


Settings controlling the type of capture to be performed, including frame limit, etc


Must be called to set up a video capture before calling RunCapture()


Begins a prepared video capture. The capture will run until any limit is reached or StopCapture() is called. The output file(s) will be named according to the selected naming scheme.


Cancel a capture that has been prepared (instead of running it using RunCapture).


Capture a single frame snapshot (the output file will be named according to the selected naming scheme

 CaptureSingleFrameTo(string filePath)

Capture a single frame and save it to the specified output file name. The path will need to be a full path and the extension specified should match that selected in SharpCap.SelectedCameras.Controls.OutputFormat.Value


The name of the camera used in the application UI


In internal identifier for the camera (may be empty or rather geeky)

 StartPreview(), StopPreview()

Start and Stop previewing frames on the camera respectively


Stop then re-start previewing frames on the camera

 GetStatus(boolean allStats)

Returns an object describing the status of the camera including frames captured, average frame rate, etc.

 IsOpen, IsPreviewing, CanCountFrames, Capturing

Informational properties, as named


The number of frames processed by the camera (including preview frames) since the last time preview was started or capture was started or stopped.


Reserved, internal use only


The following controls may be available directly on the Controls object for the SelectedCamera:

Binning, ColourSpace, Exposure, FilterWheel, Focus, Gain, OutputFormat, Resolution


Other controls are likely to be available within the Controls collection and must be searched for by name, for example:

cooler = SharpCap.SelectedCamera.Controls.FindByName("Cooler")


Note that the available controls vary from camera to camera, and only ColourSpace, Exposure, Resolution and OutputFormat are always available.

The Control Object

The following properties are available on each Control:



True if the control is actually available to read or write values.


True if the control can only be read from (for instance a sensor temperature readout)


True if the control can be set into Auto mode


Switch the control between Auto and Manual mode


The name of the control as displayed in the UI


An enumeration of common property types, currently including:   Other, Exposure, FrameRate, Pan, Tilt, Resolution, ColourSpace, OutputFormat, Focus, FilterWheel, Binning, Gain

 Minimum, Maximum

Retrieve the minimum and maximum values of numeric controls


Integer controls may have a step value defined - they can only be changed in multiples of this value. This is very rarely encountered.


The value of the control, which can be retrieved and (if not ReadOnly) changed.


The type of value that the control has.


 Numeric, whole number values


 Numeric, whole or decimal values


 On/Off value (checkbox)


 A single action, launched by a button in the UI


 A list of options, shown as a drop down control in the UI


 Any other type of control.


 In the case of a MultipleChoice control, a list of the choices available.

Direct Access to ASCOM Hardware

For each type of ASCOM hardware, SharpCap provides direct access to the ASCOM driver object, allowing scripting code to talk directly to the hardware if required.






Note that these properties will not be valid in the following situations:

·         The hardware settings for that type of hardware are set to None

·         The hardware settings for that type of hardware are set to a non-ASCOM device – i.e. a mount controlled via ST4, a manual or directly controlled ZWO filter wheel, etc.

·         The ASCOM hardware is not connected.

Care needs to be taken when using these properties to directly talk to the ASCOM hardware as this communication happens ‘behind SharpCap’s back’ – the SharpCap UI may not update correctly to reflect changes made in this way, or in some cases errors may occur if changes are made to the hardware that SharpCap is not expecting.


Scripting Samples

Examples of scripting tasks are shown below.

Periodic Capture and Timestamp Image

The code below will capture a single PNG image approximately every 15 seconds and write a timestamp into the image itself before saving it. It would be simple to modify the code to save each timestamped image under a different filename or to remove the timestamping step.

The code relies on a camera already being selected and previewing and that the camera can output to PNG files (i.e. will not work if the camera is in a 12/16-bit mode).

import time


import System.Drawing


SharpCap.SelectedCamera.Controls.OutputFormat.Value = 'PNG files (*.png)'

if (SharpCap.SelectedCamera.Controls.Exposure.AutoAvailable):

   SharpCap.SelectedCamera.Controls.Exposure.Automatic = True


while True:



   bm = System.Drawing.Bitmap("d:\capture.png")

   g = System.Drawing.Graphics.FromImage(bm)

   f = System.Drawing.Font("Arial", 12)

   g.DrawString(System.DateTime.Now.ToString(), f, System.Drawing.Brushes.Red, System.Drawing.Point(0,0))





# do more with png file here



Controlling the Selection Rectangle

Before starting this example, select either a suitable Focus Score method or the Image Histogram to enable the Selection Area generated by the program to be shown.  The Selection Area needs to be turned off via its Tool Bar icon

From Scripting > Show Console, type the following code into the IronPython Console.  Do not copy and paste as this negates the purpose of the exercise. At certain places, when ‘.’ is typed a dropdown will appear showing possible methods and properties.  Select the appropriate text.

import clr
from System.Drawing import Rectangle
SharpCap.Transforms.AreaSelection = True # turn on selection area
SharpCap.Transforms.SelectionRect = Rectangle(100,200,300,400) # adjust selection rectangle, parameters are (x, y, width, height)


The typed in code should look like this.  When run, nothing will appear to happen except an additional >>> will appear in the console.  No errors messages is a good sign. 


This enables use of the .NET type System.Drawing.Rectangle which is required to specify the selection area - the first 3 lines, which allow access to the .NET type, are the important ones here as they can be used for other .NET types too.

Example Task to Script

Consider the following non-trivial task.

·         Control a USB filter wheel containing LRGB filters

·         Capture 10x5 minute exposures using L filter

·         Switch to R filter

·         Capture 10x5 minute exposures using R filter

·         Switch to G filter

·         Capture 10x5 minute exposures using G filter

·         Switch to B filter

·         Capture 10x5 minute exposures using B filter

Total capture time = 3h 20m but no intervention is needed if the capture is managed by a script.