8
9
during daylight hours. Close-up images of birds and other wildlife or faraway
vistas can all be obtained in this way with the SSUEII. Solar images can also
be taken during the day with an optional full-aperture solar filter over the
front of the telescope.
Take some time to use the camera and Orion AmCap software during the
day to become familiar and comfortable with their basic operation. For best
results, you can optimize your images with the
camera controls.
camera controls
For best images, you can adjust the camera controls though Orion AmCap to
fine tune the image. You can see how the camera controls affect an image in
the
Live Video Window
.
From the Options menu choose
Video Capture Filter
and you can access
the camera controls under Video Proc Amp, Camera and Advanced tabs.
Here you will find the
Brightness
,
Contrast
, Gamma, Hue,
Saturation
(level
of color),
Sharpness
(keep this low as it can add noise), and
Exposure
controls.
The
Exposure
control is a gain adjustment that allows additional
flexibility in adjusting image brightness. You can either manually adjust
this by unselecting the
Auto
box and manually moving the slider
,
or have
automatic adjustment by leaving the
Auto
box selected
.
Other options
such Gamma and White Balance will aid in tuning the live view however it
is recommended to only modify exposure and brightness if images are to
be software processed later.
To return the camera controls to their default
settings, click the
Reset
button.
The other camera controls are available by selecting
Video Capture Pin
from the Options menu
. This accesses the Stream Format property sheet,
which allows you to set additional parameters. The
Frame Rate
should
generally be left at 30 frames per second for the sharpest planetary images.
This value may be overridden if the use Frame Rate box is checked in the
Capture -> Set Frame Rate menu. (You can also use the
Video Capture
Filter
selection described previously to adjust image brightness.)
Try several different settings to get a feel of how the camera controls work
and affect the resultant image on the computer screen. The
Brightness
and
Exposure
controls are the ones you will use the most. The telescope being
used, seeing conditions, and object being imaged will dictate how these
camera controls should be set. Usually Exposure will be set first and then
Brightness is adjusted as needed.
astronomical Imaging
Now that you’re familiar with basic camera and software operation, it’s time
to take the SSUEII out at night under the stars to capture some astronomical
images. We recommend starting with
the Moon, as it is easy to acquire into
the camera’s field of view, and typically
does not require stacking of multiple
exposures as planetary images do.
Imaging the Moon
Imaging the Moon is much like imaging
terrestrial objects during the day. Since
the exposure is very short, it is not
critical that the telescope be precisely
polar aligned.
When the moon is past half full,
it is hard to get detail due to the
tremendous glare off of the lunar
surface. Most detail, even on a sliver of
a moon, will be at the terminator (that
tiny thin line between the shadow and
light, see
Figure 10
). To get more of
the moon in the image, a focal reducer
will need to be used. For close-ups of
craters use a barlow lens (see “Using Focal Reducers and Barlow Lenses”).
Imaging Planets
The best planetary images will be obtained by stacking (combining) many
individual images in order to improve image contrast, brightness, and detail
(
Figure 11
).
A great way to obtain images for stacking is to take several seconds of video
of the planet, then break the video into individual frames for stacking. Since
the SSUEII has a maximum frame rate of 30 frames per second at maximum
resolution, you can literally obtain hundreds of images for stacking in
seconds! You save time by taking one video instead of dozens of individual
pictures!
Since you will be taking multiple images over a period of time, it is important
you have a decent polar alignment in order to keep the planet within the field
of view of the camera. To this end, having a motor drive (at least single-axis)
will also be helpful. Otherwise, you will periodically need to rotate the R.A.
slow-motion knob to keep the planet within the camera’s field.
tips
Focusing
One of the hardest things to do in planetary imaging is achieving good focus.
You can make this process easier by simply watching the
Live Video
window
Figure 10.
The moon’s surface detail
looks the best along the terminator.
Figure 11.
Planetary Stacking.
