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2. Keep the
Exposure Selection set to the same time you wish to use
for guiding. For example, if you choose
2.0 s, then you must keep
this exposure time while guiding for the dark frame to be effective.
3. Click
Take Dark.
4. Remove the cap from your guide scope and resume taking pictures
or guiding.
PHD Guiding will automatically subtract the dark frames
from all of your exposures. To remove the dark frame, go to
Tools
and select
Erase Dark Frame.
Advanced Autoguider Settings
The
Advanced Parameters (the brain icon) in PHD allows you to
change several settings to better customize the guiding performance
of your
SAGPRO. 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 movements
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: Allows Dec guiding to be turned on or off, or switched
which side of drift to guide on, or auto which will find the side of drift
(N/S).
Dec Algorithm: Settings that attempt to smooth the declination correc-
tions to one consistent movement and can be used to resist switching
directions 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 setting
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 guiding
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 autoguider
output for potential troubleshooting measures.
