Specifications

6 AUTOSTAR CCD PHOTOMETRY
2.4 Taking Dark Frames
The following procedure should be performed each evening, prior
to starting the imaging. Let the equipment stabilize and adjust to
the ambient temperature for at least 15 (ideally 30) minutes before
doing this. Dark Frames are used in the software to subtract the
inherent noise in the camera electronics from the images.
1. From the Image Process menu select Take Darks. (Fig. 2-4.)
Figure 2-4. Selecting "Take Darks".
Note: The default display in the blue area changes for the one
displaying the Min Quality %, Evaluation Count and Combine
check box to First Exp, Last Exp, Avg Exp and Del Existing
Darks check box. Take Darks gets put in the Object Name field
automatically.
2. Set the range of exposure times. The shortest is 1.0 seconds. Set
the First Exp (in this case 1.0), and set the Last Exp (in this case
30.0). These are default settings. This will take Dark Frames for
exposure times of1.0 through 30 seconds. If you plan a maximum
of say, 15-second exposures, then set the Last Exp to 15.
This will shorten the time it takes to make the dark frames. Use the
default value of 5 for Avg Exp (the Avg Exp is the number of
images that are averaged and stacked for each exposure time) and
select the Del Existing Darks check box. An estimated time for
taking the dark frames will be shown (for this case, the estimated
time for taking the Dark Frames from 1 to 30 seconds is 8 minutes
and 32 seconds).