A short description of the values you find there:
- Num (number of exposures) – normally set to 1. You normally want a signal output after
every guide star measurement.
- tol (tolerance) – a value that defines how much drift you allow. A good value
for the 9x50 finder is 0.1 pixel. If you use a different guide scope, add 0.1 for every 200mm
focal length.
- aggr (aggressivity) – what percentage of the calculated correction should be applied.
This is initially set to 70%, to feather overcorrection. You can play around with this later
on to reduce drift to a minimum, depending on your mount and seeing.
- mode – there are three guiding modes available, mode 2 being the preferred one. In that
mode, signals are sent to the mount even before the guide star touches the tolerance limit.
Dithering
In the main menu you find the entry "random displace". This is a special function that greatly
improves the quality of your pictures. It means that between the individual exposures of your
deep sky camera, the guider directs the guide star (and thus your camera) to a slightly
different position before triggering the next exposure. When stacking your exposures later on,
the software will stack only the stars, and the hot pixels and dark current of your camera will
be averaged out. The resulting pictures are smoother, with less noise and more weak signal
information that can be extracted in post processing. This is the gold standard in modern
astrophotography.
Naturally you must synchronize the dithering movements with your deep sky exposures. With
your DSLR or CCD connected, you can use the extensive exposure program available
in the MGEN. When enabled, dithering takes place automatically between the exposures.
(Dithering is not possible without using the exposure program unless you use APT
to control the MGEN's dithering).
Dithering is a feature you do not need to use in the beginning, but we highly recommend that
you later take full advantage of what the MGEN can do!
Some important values summarized for quick reference:
