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3.
Software Flow
This section describes the CCDOPS software from a work flow standpoint. Rather than discuss
each command in every detail which is done in the separate Software Manual, this section lets
you see the forest through the trees, describing at a high level what each command does and
why you would use it. Read this section after your first night with the camera system and it
will help chart your course for future use.
3.1.
Image Acquisition Routines
Probably the most important part of any CCD camera system is the acquisition of image data.
This section describes the various commands that can be used to take images.
3.1.1 Grab
The Grab command is the most straight forward way to take images with the camera. It's just
like pressing the button on your SLR to take a snapshot. You use the Grab command once the
camera system is all set up and focussed. In its simplest form it takes a single image of a
programmed duration and downloads it to the PC.
There are several options associated with the Grab command that expand its use. First
off, you can choose to take an auto Dark-Subtracted image or a single Dark Frame or Light
Frame. At the start you'll want to take auto Dark-Subtracted images and later, as your
experience grows, you may want to take Dark frames separately and store them on disk for
later manual subtraction from Light frames.
Another aspect of the Grab command is that you don't have to take full frame images.
You can choose to take Half Frame or Quarter Frame images where only the central half or
quarter of the field of view is captured. This has the benefit of reducing storage requirements
for images of objects such as Planets that don't fill the field of view. Along this vein, note that
you can also use the Camera Setup command described below to reduce the camera's
resolution through binning which also reduces storage requirements while preserving the field
of view.
Finally, the Grab command can be programmed to automatically display the image
after it has been acquired, or delay a number of seconds prior to starting an exposure to allow
you time to get back to the telescope and start hand guiding when desired.
3.1.2 Focus
The Focus command works like a continuous version of the Grab command. It takes images
and displays them on the computer, one after another. In its most simple form it is used to
focus the telescope and to find and center objects in the field of view.
As each image is downloaded and displayed on the screen, the Focus command
searches through the image and reports the brightness and location of the brightest pixel in the
image. Critical focus of the telescope/camera system is easily achieved by adjusting the
telescope focus until this peak value is maximized.
The Focus command can be programmed to take a partial frame image to help speed up
the image display in the Planet mode. In Planet mode you select a small region of the full
frame with the mouse and on subsequent images only that region of interest is digitized and
downloaded. For focusing on stars, this can dramatically increase the frame rate when used
with short exposures.
Section 3 - Software Flow
Page 23
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