Appendix I: Advanced Polar Alignment Procedures
As you increase the focal length of your camera lens and/or the exposure
length of your photos you also increase the need to make your polar
alignment more precise. The sign that you need to increase its precision is
elongation of the stars in your images. Errors in polar alignment cause stars
to drift off of the path your camera is making and onto new sets of pixels on
the camera sensor. The result is seen as streaks where pinpoint star images
should reside.
Fortunately, SAM is equipped with accessories to make very precise polar
alignments. The Polar Scope is the most important of these as it provides
you with a clear view of Polaris in the North and the Sigma Octanis group in
the South. Further, the Star Adventurer mini Console provides a
Po/or Clock
function to guide your polar alignment with remarkable precision.
NOTE: A Polar Scope is REQUIRED for the Advanced Alignment Procedures.
The
Equatorial Wedge
is not a requirement for the Advanced Polar Alignment
Procedure but it is a HIGHLY RECOMMENDED accessory. The fine altitude
and azimuth adjustment knobs on the
Equatorial Wedge
make precision
pointing of SAM much easier than with the comparatively coarse adjustment
resolution of a tilt/pan head or ball mount.
In the Southern Hemisphere there is the added difficulty of getting an initial,
coarse polar alignment due to the lack of naked-eye stars in the vicinity of the
South Celestial Pole. We include in the
Advanced Polar Alignment Procedure
for the Southern Hemisphere
section a detailed procedure for achieving an
initial alignment that will be sufficient to get the Sigma Octanis group into
the field of view of your Polar Scope. From that point, it is a simple matter
to achieve a very precise alignment by matching the view in the polar scope
eyepiece to the view given by the
Polar Clock
Utility provided in the Star
Adventurer mini Console.
NOTE: Because the
Equatorial Wedge
is such a highly recommended option
30
Star trails can make beautiful pictures, but
only when then are intended! SAM elim
inates trailing over long exposures to give
you pin point star images.
V
the following sections assume that you are using one. If you are not, you
can still follow the procedures, but by making the indicated adjustments
with your tilt/pan head or ball mount. We also highly recommend the
Fine
Tuning Mounting Assembly
as it enables you to perform the advanced polar
alignment procedures with your photographic payload already attached to
SAM and without the need to remove the polar scope once the procedure
is done.
Advanced Polar Alignment for the Northern Hemisphere
Start by Achieving a Coarse Polar Alignment
Attach the
Equatorial Wedge
(wedge) to your tripod via the 3/8 inch
mounting bolt (or using the 1/4 inch thread adapter if required).
Attach SAM to the
Equatorial Wedge.
Level the tripod so that the bubble level on the wedge is centred. A
level tripod is not a strict requirement, but it does make subsequent
adjustments easier.
Turn the
Latitude Adjuster
to match the latitude of your location.
This will angle SAM to the correct level to obtain your coarse polar
alignment. You can use the Star Adventurer mini Console to get your
latitude if the GPS function of your phone is enabled.
Look through the
Polar View Finder
and adjust your
Altitude
and
Azimuth Knobs
until you can see Polaris inside the boundaries of the
view port. Note that if SAM is powered up you can illuminate the
Polar
View Finder
LED by turning it on in the Star Adventurer mini Console,
or quickly pressing and releasing the power button.
Once you can see Polaris in the view finder you are ready to install the
Polar
Scope
and fine-tune your polar alignment with the
Polar Clock
function.
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