Meade Deep Sky Imager, Руководство пользователя, Страница: 35 / 58

Dark Frames is a useful feature for if you’re taking exposures longer than 1 second.
Longer exposures and temperature can create noise in your Deep Sky Imager camera called dark current
artifacts. The Dark Frames feature allows you to subtract out some of this noise from your pictures.
Delete Existing Dark Frames. Deletes and overwrites previously imaged dark frames. This is box is left
unchecked as a default.
Total Time. Displays how long it will take to create all the dark frames using the Dark Frame settings chosen by
the user
Perform the Dark Frames features at night. If the temperature changes
significantly during your observing session, you should repeat this procedure.
To perform the dark Frames procedure:
1. Select “Take Dark” in the Image Process combo box (10). The Dark Frame Exposure controls display.
2. Select a range of exposure time. For example, if the length of your exposures will be between 2 and 5
seconds, set the First Exp (Exposure) box for 2 seconds and the Last Exp box for 5 seconds. The Envisage
program will then take a series of dark frames image files between 2 seconds and 5 seconds in length at
approximately 1 f/stop intervals. Later, when you set your camera exposure time (see Step 6 below), the
Envisage program will automatically select the Dark Frame file with the closest exposure length, temperature
and proper binning, and apply it to the image you are taking. In effect, it subtracts out the dark
current
artifacts.
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