seeing conditions, wind, or a shaky mount, however, increasing the Frames
to more than 1 will generally decrease image quality. You can take many
individual frames and add them together (“stacking” or “combining”) later,
this will be discussed in detail in the “Astronomical Imaging” section.
11. Select the Single beneath the Mode box in the Camera Control
Window.
12. Keep the Calibrate box unchecked in the Camera Control Window.
13. Click the Expose button in the Camera Control Window. An image will
appear in a window.
14. You can save the image for processing later, if you wish. This is done by
selecting Save from the File menu.
You have now taken your first picture with the SSSSI-III! This simple method
of imaging is exactly how the camera is used to capture terrestrial subjects
during daylight hours. Close-up images of birds and other wildlife or faraway
vistas can all be obtained in this way with the SSSSI-III. Solar images can also
be taken during the day with an optional full-aperture solar filter over the front
of the telescope.
Take some time to use the camera and MaxIm DL Essential software during the
day to become familiar and comfortable with their basic operation. For best
results, you can optimize your images with the camera controls.
Camera Controls
For best images, you can adjust the camera controls though MaxIm DL
Essentials to fine tune the image. You can see how the camera controls affect
an image in the Live Video Window.
In the Camera Control Window, click the Setup button, then choose Video
Capture Filter and you can access the camera controls. Here you will find
the Brightness, Contrast (best at 50% or higher), Hue, Saturation (level of
color), Sharpness (keep this low as it can add noise), and Exposure controls.
The Exposure control is a gain adjustment that allows additional flexibility in
adjusting image brightness. You can either manually adjust this by unselecting
the Auto box and manually moving the slider, or have automatic adjustment
by leaving the Auto box selected. For usual operation, the ColorEnable box
should remain checked. For black and white camera operation, uncheck this
box. The Cancel Flicker button enables and disables the flicker function. The
default has the flicker function disabled, and there should be no reason to use
this function with normal usage of the camera. If the image in the Live Video
Window begins to flicker on and off, the flicker function has been mistakenly
enabled; click the Cancel Flicker button to cancel this function. To return the
camera controls to their default settings, click the Default button.
The other camera controls are available by clicking the Setup button, and
selecting Video Capture Pin. This accesses the Stream Format property
sheet, which allows you to set additional parameters. The Frame Rate, while
generally should be left at 15 frames/second for the sharpest planetary images,
can be toggled down to 7.5 frames/second for brightest exposures. (You can
also use the Video Capture Filter selection described previously to adjust
image brightness.) Check the Flip Horizontal box to change the orientation of
the image display in the Live Video Window. Color Space / Compression
selectsthecodecusedbythecamera;inthiscaseitisRGB24.TheOutput
Size can be used to shrink the image size if desired; the camera defaults to
640x480, but you should raise this to the highest setting (1280 x 1024) for the
maximum possible resolution. The other parameters shown with the Video
Capture Pin selection cannot be adjusted.
Try several different settings to get a feel of how the camera controls work
and affect the resultant image on the computer screen. The Brightness and
Exposure controls are the ones you will use the most. The telescope being
used, seeing conditions, and object being imaged will dictate how these cam-
eracontrolsshouldbeset.UsuallyExposurewillbesetrst,thenBrightness
is adjusted as needed.
Screen Stretch Window
The function of the Screen Stretch Window (Figure 6) is to properly map the
image brightness levels captured by the camera into corresponding image
brightness levels on the computer screen. A typical camera image has each
pixel (light detecting site, over 1,300,000 pixels form a single SSSSI-III image)
represented as a number depending on brightness. This has to be mapped
into the video monitor’s brightness range. It is important to set the screen
stretch appropriately, or a great image may look terrible!
Figure 6. The settings in
the Screen Stretch Window
greatly determine how an
image will appear on your
computer screen.