The Tool Bar


Start Capture

The Start Capture button will start a video capture to a new file.  The functionality is identical to choosing Capture > Start Capture from the menu.  See Capturing Videos and Images for a full description.

Quick Capture

Clicking the Quick Capture button will initiate a video capture to a new file but use a pre-selected number of frames or seconds. 


To modify the pre-selected value, click the down arrow and select a new value.  This value will be ‘remembered’ for future quick captures.





<ALT> < Q> can be used as a hot key combination to initiate a Quick Capture.

Stop Capture

When a capture is in-progress, the Stop Capture button will be available and will stop the current capture.


When a capture is in-progress, the Pause button will be available and will pause capture.  This is useful if a cloud is passing over the object of interest.  Pause only works for DirectShow cameras in SharpCap 2.9, but will be available for a much wider range of cameras in 2.10.


The Snapshot button will capture the current image as seen in the display area to a PNG or FITS file.  The location of the captured file appears in the Notification Bar below the Tool Bar, for example:


<ALT> <A> can be used as a hot key combination to initiate a Snapshot.

Live Stack

This button initiates the Live Stack process.  The functionality is identical to choosing Tools > Live Stack.  See Live Stacking for a full description of the tool.

<ALT> < L> can be used as a hot key combination to initiate Live Stack.

Object Name

Selecting Object Name in the main toolbar allows a pre-defined object to be selected and used as part of the capture folder hierarchy.


A new name can also be typed here to represent the current object of interest –  such as M42 or Orion Nebula.


 Subsequent captures would be saved in a sub-folder called M42 (or Orion Nebula) under the default capture folder.  Objects added here will not persist across SharpCap restarts.  To become permanent, the object must be added via File > SharpCap Settings > General tab.

This tool is convenient for self-documentation purposes (in the capture folder name hierarchy) during an imaging session.  For example, names such as ‘M42 CLS filter’ and ‘M42 f6.3 reducer’ can be created to identify equipment used for a capture.

Preview FX (effects)

The Preview Effects, FX, dropdown contains the options shown below. 


When an FX option is chosen, the FX Selection tool from the tool bar becomes active.


A red rectangle, which can be dragged and re-sized, appears on the image.  In this way, the special effect can be applied only to the selected area. 


Preview Effects (FX) will apply only to the display and not affect the captured data.

This tool can also be used with the Image Histogram and Calculate Focus Score tools to limit an action to a section of the image.


No effects are applied to the image.

Highlight Over Exposed

Any part of the image which is deemed to be over exposed is highlighted in red.  In this graphic, notice the red highlighted areas.


This is a more extreme example using the moon – the camera exposure setting needs to be reduced to remove the red highlighted area.


Image Boost

Image Boost is useful when trying to find fainter objects.  The image will appear slightly grainy as noise is introduced.


Image Boost More

Image Boost More applies a greater boost to the image, allowing even fainter objects to be revealed.  An increase in graininess is to be expected.


Frame Stack (3)

With Frame Stack (3), 3 images are stacked.  This effect can assist when looking for fainter objects. Stacking when this option is applied does not attempt to align new images with previous images in the stack.


Frame Stack (5)

With Frame Stack (5), 5 images are stacked.  This provides a further boost to brightness when trying to locate faint objects.


Frame Stack (10)

With Frame Stack (10), 10 images are stacked. 


RGB Align

RGB Align can be used for planetary imaging when, due to atmospheric conditions, the object being imaged has colour distortion at the edge.  In this extreme example, note the red on one side and the blue on the other, caused by the varying refraction of colours of light as they enter the atmosphere.


Use this option to adjust the red/blue values to obtain a good image on screen to ensure best focus when preparing to capture.  The right-hand image shows the same view of Jupiter with the colour channels aligned.


RGB Align applies only to the previewed image, it does not affect the captured data.  Other programs, such as Registax, allow re-alignment of RGB channels in the final captured images.

Since the RGB align only affects the image as displayed on screen, its main use is to correct for RGB misalignment to allow a better judge of focus quality to be obtained, or for live broadcasting of planetary imaging.

Stop Motion Video

This option will terminate an in-progress video capture.  A basic tool to allow stop motion frames to be captured from any camera supported by SharpCap.

FX Selection Area

The FX Selection Area tool creates a red selection rectangle on the image which can be dragged and re-sized.  This selected area is used when applying special effects (FX) or when using the Calculate Focus Score tool.


The FX Selection Area tool can also be used to investigate the histogram of a reduced area when using the Image Histogram tool.

Reticule Overlays

The Reticule Overlay tool has 3 options.


By repeatedly clicking the icon located in the Tool Bar, the display area will cycle through the reticule options.  The reticule can be selected directly by using the drop-down menu to the right of the button.

·         The reticule can be ‘grabbed’ by the mouse and moved around in the display area.

·         When the reticule is displayed, the centre point can be moved by clicking anywhere on the preview display.

·         Dragging or clicking with the right mouse button instead will adjust the orientation or size of the reticule.

For some cameras, 'Auto' output format selection will be chosen by default. You can turn off auto selection and select an output format manually or disable 'Auto' being the default in the settings.

'Auto' output format will typically pick the best output format for the exposure and colour space selected. For short exposures (<5s) a video format will be chosen, for longer exposures a still format will be chosen.

'Auto' will select basic output formats (avi, png) where they support the colour space being used, otherwise it will pick advanced output formats (ser, fits) - for raw capture or 16 bits per pixel.

For most cameras except Webcams and Basler Cameras, SharpCap now supports a live stacking mode where many short frames can be added together and faint images will appear in real time.

When you select Live Stacking from the toolbar you will be able to see details of your stack so far (number of frames, total exposure, histogram) and you have the ability to clear and save the stack. You can also adjust the white and black levels used when generating the display image from the stack (these adjustments will not affect the saved files).

Saved stacks are always saved in .fits format and will be named using the same rules as any other captured image.

SharpCap will warn you if the frame rate is too fast for the live stacking code to keep up.

For all supported cameras (except DirectShow cameras), SharpCap includes a 'Display Controls' group in the control panel. These controls allow you to adjust the brightness, contrast and gamma used to display images, allowing you to bring out faint detail easily. They provide similar effect to the 'Image Boost' options in the FX dropdown but with finer control.

Making adjustments to the controls in the Display Controls section only affects how the images are displayed on screen - it will not make any changes to the images saved to any capture files.

Any camera controls that show a numeric value (gain, exposure, brightness and many others) can be changed by typing a new value into the display box and pressing <Enter> or <Tab>. If you type a value that is out of range, the value will be ignored.

For the exposure control, you can type a new exposure value with appropriate units, i.e. 15ms or 10s (Sadly last bit this doesn't work for most DirectShow cameras, which only accept exposures as numbers like -3 or -5).

Cameras that you access using DirectShow (webcam) drivers have a rather odd way of controlling exposure. Unfortunately there's not a lot SharpCap can do to improve this as the way to control exposure was designed by Microsoft when they created DirectShow many years ago...

A DirectShow exposure value is a whole number. Zero indicates a 1 second exposure, negative values (most common) are exposures of less than one second, positive values (rare) are more than one second. Every change of the value by 1 is a doublying or halving of the exposure. That means that -4 is 1/16s and +4 is 16s; -6 is 1/64s and -8 is 1/256s.

Unfortunately, some webcam driver writers got this wrong (Logitech even got it the wrong way round in their drivers for several years), so some cameras don't actually obey these rules.

SharpCap can add a timestamp showing the date and time to captured frames from many cameras. Supported cameras include ZWO, QHY, Altair and iNova cameras, and DirectShow cameras when capturing in MONO8 or RGB24 format.

DirectShow cameras capturing in compressed formats (I420, MJPG, YUY2, etc) are not supported as SharpCap would need to decompress, alter and then recompress each frame.

If you are running out of space on your screen, you can make the SharpCap control panel auto-hide itself by clicking on the pin icon to the left of its title. Once you have clicked the pin, the control panel will hide itself when you move your mouse away from it and reappear when you move the mouse back. Click the pin again to go back to the default behaviour.

You can also drag the control panel to the left hand side of the SharpCap window or detach it from the window completely.

Capture Profiles allow you to save all the settings for a camera once you have adjusted them to your satisfaction. You can save multiple profiles and give them useful names (Moon, Jupiter, Saturn, etc). SharpCap automatically adds the camera name to the name you enter for each profile - after all, you may well need different settings for the same target depending on which camera you are using.

You'll find capture profiles at the top of the control panel. To create your first profile, get the camera settings adjusted as you want them and then click the 'New...' button.

You can also set a profile as default. Each camera can have its own default profile. The default profile is loaded automatically when the camera is started. This is a great way to set a default exposure, gain, resolution etc. each time you open a particular camera.

When you select a camera in SharpCap (or SharpCap automatically selects a camera when it is started), SharpCap starts grabbing and displaying frames from that camera straight away. Don't worry - SharpCap isn't saving these frames, just showing them on the screen. SharpCap will only save images after you've used the 'Start Capture' or 'Snapshot' buttons.

You might think of the automatic preview as being a bit like looking through the viewfinder of a camera.

If you are using an ASCOM focuser from withing SharpCap and you use one of the focus aids that displays a graph (FWHM or Contrast detection), SharpCap will display a trace of the focuser position overlaid on the focus score graph.

This can be very helpful as you can see which position on the focuser gave the best focus score. Remember that most focusers have some degree of mechanical backlash, so always aim to approach the target score from the same direction.

If you want to enable the alignment feature in Live Stacking, you need to make sure that SharpCap can detect at least 3 stars on each frame. SharpCap looks at the shapes of triangles it can create from the stars it finds to work out how to align each frame onto the stack.

To adjust the star detection parameters, go to the 'Alignment' tab in the Live Stacking window. You can make SharpCap highlight the stars it is using (yellow box) and other stars it has found (red box).

SharpCap polar alignment works by plate solving two fields of stars near the celestial pole and comparing the point that they rotate around with the position of the pole. SharpCap will then guide you through making the Alt/Az adjustments needed to correct any alignment error.

Select 'Polar Align' from the Tools menu and follow the instructions. You will need a field of view of bewteen 0.5 and 2.5 degrees (a guide camera in a 200mm finder-guider works well) and a camera with square pixels (the aspect ratio of the image on screen must not be distorted).

Just tick the 'Save Individual Frames' checkbox. Each frame that is added to the stack will be saved as a PNG file (for 8 bit frames) or a FITS file (16 bit frames). Frames that are not added to the stack due to filtering, frame rate or alignment issues will not be saved.

Enable any focus score method and then select the 'Graph' tab (shown to the right of the main history chart). This shows how the focus score changes with different focuser positions.

Green upward pointing triangles show points where the focuser was last moved in the +ve direction, red downward pointing triangles show points where it was last moved in the -ve direction. Older points are shown with paler colours. To get best focus, move the focuser through a range of values in one direction to find the best score achievable and the position for it, then go back to that point making sure you arrive moving in the same direction to avoid backlash problems.

As well as collapsing any control groups that you don't often use, you can also change the order of the control groups by dragging them into a new order using the drag grip (three horizontal bars) to the right of the group title.

Use 'Capture Dark...' from the Capture menu to start capturing a dark frame. You can choose the number of source frames to average and SharpCap will do all the work for you. SharpCap will also file the newly created dark frame in a folder structure split up according to camera, resolution, exposure, gain and temperature, to help you find the correct dark frame later on.

You can apply a dark frame by selecting it using the 'Browse' button on the 'Subtract Dark' control in the preprocessing group. When you browse for a dark, SharpCap will automatically start you in the most appropriate folder in your SharpCap dark library.

Using dark frame subtraction will apply not only to the frames as displayed on screen but also to the captured frames saved to file. Note that for webcams and frame grabber devices you can apply a dark frame in the Live Stacking options only (not in the main camera controls).

No Reticule

The graphic is cleared from the image.  This is the default.


A crosshair graphic is imposed over the image in the display area.  This can be used to facilitate accurate mount alignment using a camera rather than an eyepiece.



A circular graphic is imposed over the image in the display area.  This can be used to facilitate accurate mount alignment using a camera rather than an eyepiece.  The rings can also be used to assist with collimation.



The Zoom tool gives the ability to zoom in or out of the image in the Capture Display Area

This feature can be used to:

·         Zoom in when searching for fainter objects.

·         Zoom in when trying to place the FX Selection Area over a single-star when using the Calculate Focus Score tool.

·         Zoom in when trying to accurately set the Black Level % when using the Calculate Focus Score tool.

·         Zoom out to reduce the image when Live Stack or Image Histogram are in use.

·         Zoom out to reduce the image size displayed when capturing at higher camera resolutions.


·         Zoom has a range of 16% - 800%. 

·         Auto zoom is a sensible working setting for most purposes – it will fit the image to the screen space available.




Image Histogram

A correctly shaped Histogram is a key requirement to producing quality images. 

Clicking the Image Histogram icon in the Tool Bar:


will display the Image Histogram in the Work Area of the Main Screen.


See The Histogram for a full description and examples including information on logarithmic versus linear scales and the impact of solar/lunar/planetary/deep sky/ROI on the shape of a histogram.

Calculate Focus Score

SharpCap has a several options to help acquire focus on targets (possibly one of the most challenging aspects of astrophotography).  The tools are particularly powerful if an ASCOM focuser is configured in SharpCap.

Focus assistance is started by selecting the Calculate Focus Score icon from the Tool Bar.   


Focus tools for planetary or surface targets:

·         Contrast (Edge) Detection

·         Contrast (Brightness Range) Detection

·         Fourier Detail Detection

Focus tools for stars or other point sources:


·         FWHM Measurement

·         Multi-Star FWHM Measurement

·         Bahtinov Mask

See Focusing for a full description including introductory materials and examples.