Orion 52175 instruction manual Camera Controls, Astronomical Imaging, Tips

Camera Controls

For best images, you can adjust the camera controls though Orion AmCap to fine tune the image. You can see how the camera controls affect an image in the Live Video Window.

From the Options menu choose Video Capture Filter and you can access the camera controls. Here you will find the Brightness, Contrast, Gamma, 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 manually adjust this by moving the slider. To return the camera controls to their default set- tings, click the Default button.

When the moon is past half full, it is hard to get detail due to the tremendous glare off of the lunar surface. Most detail, even on a sliver of a moon, will be at the terminator (that tiny thin line between the shadow and light, see Figure 7). To get more of the moon in the image, a focal reducer will need to be used. For close-ups of craters use a Barlow lens (see “Using Focal Reducers and Barlow Lenses”).

Figure 7. The moon’s surface detail looks the best along the terminator.

The other camera controls are available by selecting Video Capture Pin from the Options menu. 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. This value may be overridden If the use Frame Rate box Is checked in the Capture -> Set Frame Rate menu. (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. The Output 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.

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

Imaging Planets

The best planetary images will be obtained by stacking (combining) many individual images in order to improve image contrast, brightness, and detail.

A great way to obtain images for stack- ing is to take several seconds of video of the planet, then break the video into individual frames for stacking. Since the SSSSI-IV has a maximum frame rate of 15 frames per second at maximum reso- lution, you can literally obtain hundreds of images for stacking in seconds! You save time by taking one video instead of dozens of individual pictures!

Figure 8. Jupiter with Ganymede and shadow in transit. Left. Live image Right. 500 frames Aligned, stacked and enhanced using Registax Image Processing Software. Image taken with Orion 180mm Mak-Cass telescope.

used, seeing conditions, and object being imaged will dictate how these cam- era controls should be set. Usually Exposure will be set first, then Brightness is adjusted as needed.

Astronomical Imaging

Now that you’re familiar with basic camera and software operation, it’s time to take the SSSSI-IV out at night under the stars to capture some astronomical images. We recommend starting with the Moon, as it is easy to acquire into the camera’s field of view, and typically does not require stacking of multiple exposures as planetary images do.

Imaging the Moon

Imaging the Moon is much like imaging terrestrial objects during the day. Since the exposure is very short, it is not critical that the telescope be precisely polar aligned.

Since you will be taking multiple images over a period of time, it is important you have a decent polar alignment in order to keep the planet within the field of view of the camera. To this end, having a motor drive (at least single-axis) will also be helpful. Otherwise, you will periodically need to rotate the R.A. slow- motion knob to keep the planet within the camera’s field.

Tips

Focusing

One of the hardest things to do in planetary imaging is achieving good focus. You can make this process easier by simply watching the Live Video window to focus. Depending upon the viewing conditions you may notice that the image goes in and out of focus, this is due to viewing conditions. This is to be expected and one of the reasons why post processing software can bring out the best in your captured images. Focus as best as possible with the average frame being at best focus to ensure more in focus frames than out of focus.

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