Stop button in the Camera Control Window | Orion 52080 specification

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

Figure 9. The settings in the Screen Stretch Window greatly determine how an image will appear on your computer screen.

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.

Number of pixels at brightness level

Range of brightness levels

Figure 10. A histogram is a visual representation of the range and levels of brightness in an image.

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