Autoexposure Function (Ae); Random Displacement Function (Rd) - Lacerta M-GEN User Manual

The Firmware handles sudden lose of the Camera but it is not safe to power-off it
that way, it might damage some circuit part in the Camera.

4.2 AutoExposure function (AE)

The Autoexposure functional unit is also a separate part of the software. On its dedicated
screen can be set up, started and stopped etc. The shutter signals generated by this functional
unit appear on the 3.5mm stereo jack output connector and can be directly connected to a
Canon EOS 350D or similar DSLR with such a shutter input ("open-collector" line). The
AE's function is to shutter Your DSLR synchronized with the device's functions.
The AE program runs totally independently of the other units by default. In this case it can
be used as a single automatic shutter device too, can be powered only from USB as well. The
only case when the AE is synchronized with other functional units is the Random
Disaplacement function enabled and the Autoguiding active.
The shutter program has two operational modes:
o Normal mode (default): all the shutter program parameters can be set and used
(wait time, mirror lockup time etc.), the DLSR shutter is controlled fully by the
LMG device.
o "AstroTimer" mode: this mode is mainly for cooperating with the external shutter
device called AstroTimer but other external device may be used.
In this mode the device does not generate shutter signals but other: the shutter
output is only active when the Random Displacement function is moving the
telescope, so it indicates the time when the external shutter device must wait.
In this mode there is only one parameter that can be set, the time period between
two RD movements. It is shown as the 'exposure time' of the program.

4.3 Random Displacement function (RD)

Also known as "dithering". It's goal is to move the telescope (with relocating the guide
star) randomly between the imaging exposures, avoiding to image the object time to the same
sensor surface each time. This has several advantages:
 Some untouched or 'termporary' hot pixels can be eliminated automatically at the
combination ('averaging') of the single frames. These pixels will be located at
different position on each frame relative to the object (after registering /
alignment).
 Similar to this, overcompensated pixel caused 'black holes' are eliminated also
and the noise effect of 'wrong' dark frame subtraction is smoothed.
 The non-uniformity of pixel sensitivity causes extra noise pattern that can be
suppressed (smoothed) too.
 Using very short focal length objective and a sensor with Bayer-matrix color filter
can cause false coloured star spots as they are easily imaged into a single pixel. By
moving the image over the filter matrix will lower this 'color noise'.
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