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Advanced Autoguider Settings
The
Advanced Parameters (the brain icon) in PHD Guide allows you
to change several settings to better customize the guiding performance
of your SSAG. Under normal use, you should not have to make any
major adjustments to the
Advanced Parameters. All of the calibra-
tion and autoguiding is done automatically simply by pressing the
PHD
Guide icon. However the following settings can be adjusted to cater to
your specific guiding setup:
Advanced Parameters
R.A. Aggressiveness: Adjusts the percentage of R.A. correction per
step. The default value is 100, meaning that the guider will move the
full distance of the correction. If the seeing conditions are not steady,
the aggressiveness can be turned down to smooth out the quick move-
ments and reduce the correctional movement.
R.A. Hysteresis: Implements a percentage of the previous averaged
tracking corrections to the current tracking corrections. This setting can
be useful if you are experiencing some wind or severe periodic error,
since the guider will partially ignore some of the radical movements
and repeat a percentage of the previous tracking corrections.
Dec Guide Mode: This setting should not be changed under normal
use. You can optionally disable dec guiding, or limit which direction the
guider will allow dec to be corrected on (north or south). The default
setting automatically finds which side dec is drifting (north or south).
Dec Algorithm: Ideally corrections made in declination should only be
one consistent direction, usually based on how well the mount is polar
aligned. The
Dec Algorithm takes this into account and attempts to
keep the declination tracking consistent. Choose
Resist switching or
Lowpass filter which are algorithms that try to keep dec on one side
of drift, or average the corrections made in dec.
Calibration Step: Adjusts how long each guide pulse is during cali-
bration. The default is 500 milliseconds. The calibration step can be
increased to provide a better sample of movement. However, if the cali-
bration step is increased too much, the guide star will move out of the
camera’s field of view during calibration.
Min. Motion: Number of pixels the star must move before PHD will
make a guiding correction. The default is 0.25 pixels.
Search Region: The area in pixels that the guide star is searched for
and looked at. The default is 15x15 pixels. Under normal use, this set-
ting should not be changed.
Noise Reduction: Choose from 2x2 mean or 3x3 median to smooth
out noise and blur out hot pixels.
Time Lapse: This setting optionally sets a delay between each guid-
ing correction. For mounts that track exceptionally well, you can add a
delay between each correction.
Gain: The gain adjusts the camera’s internal brightness level and sen-
sitivity. The default is 95%. If you are experiencing excessive noise or
hot pixels, you can reduce the gain. The camera remains very sensitive
as low as 50% gain. If you are guiding on a very bright guide star, you
can afford to turn down the gain and further decrease the noise in your
image.
Force Calibration: Enabling this setting makes PHD Guide calibrate
every time a new star is chosen. If you move your telescope to another
object in the sky, you will need to recalibrate the autoguider. The
default has this setting enabled.
Log Info: You can log all actions into a text file saved in the PHD direc-
tory.
Disable Guide Output: This setting deliberately shuts off the autogu-
ider output for potential troubleshooting measures.
Tips & Tricks
If all conditions are ideal, and your tracking is superb, you typically do
not have to alter any of the camera’s default settings. However, if your
setup is tracking much worse than usual (such as a night with high
wind or poor seeing), you may need to customize your settings to bet-
ter adapt to the current conditions in the field.
