Orion 52083 - Manual (Page 21)

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To automatically subtract the averaged dark frame from “light” images as they
are captured:
1. Setup the averaged dark frame as outlined previously.
2. Acquire the deep sky object into the field of view of your eyepiece, and
center it in the eyepiece’s field of view. Focus the eyepiece with the
telescope’s focuser. Make sure your equatorial mount’s motor drive is on
and engaged. Remove the eyepiece and replace it with the SSDSMI-2.
If the parfocal ring was set properly on the eyepiece, the camera should
be close to focused. Precisely focus the camera by using the telescope’s
focus knob and the Fast Focus (or Focus) setting in the Camera Control
Window.
3. In the Camera Control Window, click the Dark Subtract square so it is
checked. Once this box is checked, every subsequent light frame taken
with the camera will have the averaged dark frame automatically sub-
tracted.
4. Now, set the Mode to Light 1x1. In the box under the Mode box, select
AutoSave. Set the number of images you would like the camera to take
under Autosave (start with 5 or so), select the file folder in which you would
like to save the images with Folder, and enter in a Base filename for the
captured images. Set the exposure time equal to that of the dark frames
taken prior.
5. Click Expose, and the camera will commence taking the images. When it
saves each image file to its designated Folder location, it will automatically
subtract the averaged dark frame.
These images have the averaged dark frame subtracted. These are now ready
for stacking (using the Combine function). You can Save the individual images,
or just save the combined image after stacking.
If you have already taken your “light” images, then you will need to manually
subtract the averaged dark frame from each image prior to stacking them into
one combined image. To do this:
1. Open all “light” images to be stacked in Maxim DL Essentials. Do this with
the Open command in the File menu.
2. Click on one of the opened images, and select Dark Subtract from the
Process menu. The averaged dark frame has now been subtracted from
the selected “light” image. Repeat this process for all of the “light” images
opened in Maxim DL Essentials.
You can save each image after dark frame subtraction and color conversion
(using Save from the File menu), or you can just save the final combined image
once the individual images have been stacked using the Combine function.