Orion 52080 User Manual
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Note: The camera’s field of view is fairly small. It is approximately equivalent to
the field of view through the telescope when looking through a typical (i.e. not
wide-field) 10mm focal length eyepiece. So make sure the object to be imaged
is well centered in the telescope before connecting the SSDSI-II, otherwise it
may not appear in the field of view of the camera
.
10. Once focused, image orientation can be changed by rotating the camera
within the focuser drawtube. Simply loosen the thumbscrew on the draw-
tube and rotate the camera until the desired image orientation is achieved.
Retighten the thumbscrew on the focuser drawtube when done. You may
need to slightly refocus (using the telescope’s focus knob) if the focuser
drawtube has moved a bit inward or outward when the camera was rotat-
ed.
11. When the image is focused and the image looks acceptable, press the
Stop button in the Camera Control Window.
12. Beneath the Mode box in the Camera Control Window select Single.
13. Click the Expose button in the Camera Control Window. An image will
appear in a window.
14. You can now save the image for later processing, if you wish. This is done
by selecting Save from the File menu.
You have captured your first image with the SSDSI-II! This simple method
of imaging is exactly how the camera could be 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 SSDSI-II. 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.
Note: In the Camera Control Window, there is a
Setup button. Clicking on
this button will allow you to toggle the High Speed Readout Mode on and
off. High Speed Readout Mode should generally be left on unless there is a
specific reason (i.e. your computer system cannot process the higher speed
readout) to turn it off.
Screen Stretch Window
The function of the Screen Stretch Window (Figure 9) 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 437,000 pixels form a single SSDSI-II image)
represented as a number (from 1 to 65535) depending on brightness. This has
to be mapped into the video monitor’s brightness range (from 1 to 255). It is
important to set the screen stretch appropriately, or a great image may look
terrible!
When an image is displayed, you will notice a graph in the Screen Stretch
Window. This is called the “histogram” of the currently displayed image (Figure
10). A histogram is a simple bar graph that shows the range of brightness in
an image. Each bar in the graph represents a level of brightness; the bar to
the far left in the histogram represents the dimmest pixels, and the bar to the
far right is for the brightest pixels. The height of the bar is the total number of
pixels at that brightness level in the image. Every image has a different histo-
gram depending on how much of the image is bright or dark. Directly viewing
the histogram of your image in the Screen Stretch Window provides an easy
interface for making decisions on how the screen stretch should be set.
In Maxim DL Essentials, the two parameters entered in the Screen Stretch
Window are Minimum and Maximum. A pixel that is at the Minimum value
is set to zero (black), and a pixel at the Maximum value is set to 255 (white).
An easy way to adjust the Maximum and Minimum values is to move the
slider arrows located directly under the histogram of the image in the Screen
Figure 9.
The settings in the Screen Stretch Window greatly determine how an
image will appear on your computer screen.
Figure 10.
A histogram is a visual
representation of the range and levels
of brightness in an image.
Number
of
pixels
at
brightness
level
Range of brightness levels