• gth thermal noise from the image;
• — —oTH thermal noise from the scaled dark frame; /THV t
• aR0 readout noise from the image; and
• — aR0 readout noise from the scaled dark frame.
The integration time used for the dark frame should be at least five times longer than the integration time used for the raw images. This strategy minimizes the value of the thermal noise and the number of readouts necessary.
• Tip: In AIP4Win, you can enter the ratio of the integration times or allow the program to match the dark frames automatically.
After dark subtraction, the image is flat-field corrected in exactly the same way as it is flat-fielded in the standard calibration protocol.
• Tip: AIP4Win automates advanced image calibration. After the observer sets up the master dark, master flat, and master bias frames, and selects a method of scaling the thermal data, the current image can be calibrated with one click. Using the Auto-Process Tool, you can automatically calibrate all of your raw images from a long observing session.
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