The StellarMate X Manual
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settings. There are basically five primary types of frames:
1.
Light Frame: This is the regular image captured by your sensor. It is called light
because it captures the incoming light received at the sensor.
2.
Dark Frame: A frame captured with the same settings as the light frame (same
temperature, exposure time, and binning) but with the shutter closed so that no
photons reach the sensor. This is used to record the electronic noise generated by
the sensor without any incident photons. It is used to remove noise from the Light
Frame by means of subtraction since the Light Frame includes signal from both the
incoming photons and electronic noise generated by the sensor.
3.
Bias:
A very short exposure with the shutter closed.
4.
Flat:
A frame captured with the same settings as the light frame (same temperature,
exposure time, and binning) but subjected to an illuminated flat field source (such as
an LED panel). This is used to correct for optical aberrations in the imaging train
including dust motes.
5.
Dark Flats: Special type of dark frames captured at the same exposure of flat
frames. This is used to calibrate the flat frames.
Dark Library is used to capture dark images.
Generating a dark library for your equipment profile is highly recommended. When
capturing frames in focus, guide, and align modules, the system searches the dark library
for suitable dark frames. If a suitable match is found, the light frame is calibrated and this
can greatly enhance the performance and accuracy of all Ekos modules.
Note: "Dark Library is not used to calibrate your sequence images, it is only used to
calibrate the Align, Focus, and Guide module frames."
Dark frame calibration can be applied using two methods:
1.
Dark Subtraction
: The dark frame is simply subtracted from the light frame. This is
the recommended method when using a cooled camera.
2.
Defect Maps: For uncooled cameras (e.g. Guide), dark frames may not be suitable
for removing the hot and pixels present in the image. An alternative method
generates a map of bad pixels that should be treated in the light frame. You can
adjust the Hot and Cold pixels sliders to include or exclude pixels. It’s recommended
not to include more than 5,000 pixels as it can become computationally expensive to
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