ASTRO-PHYSICS Mach1GTO, Руководство пользователя, Страница: 10 / 31

Altitude and Azimuth Adjustments - Rough polar alignment
For rough polar alignment, your goal is to sight the
celestial pole when looking through the polar
alignment sight hole in the center of the polar axis.
You will need to make altitude (up/down) and
azimuth (side-to-side) adjustments to the position
of the mount. Before beginning, make sure that
the mount is pointing roughly north using the built-
in compass and that your pier or tripod is level
using the mount’s built-in bubble level.
Remember that magnetic north is not the same as
true north and varies both with time and with your
location. In the fall of 2006, on the northeast tip of
Maine, for example, magnetic north is west of true
north by a whopping 18 1/2 degrees! On Mauna
Kea in Hawaii, by contrast, magnetic north is
about 9 1/2 degrees east of true north. Observers
along the Mississippi River are lucky and are
nearly dead on. These values change by several
minutes every year. With experience at a
particular site, however, you will soon learn to use
the compass to find true north. (You will know just
how far off magnetic north is for your location.) In
addition, there is a website funded by our U.S. tax
dollars that will compute the declination of
magnetic north relative to true north for any
location that you input. The link is as follows:
http://www.ngdc.noaa.gov/seg/geomag/jsp/Declin
ation.jsp
Note: It is possible to achieve perfect polar
alignment without having the pier level, but it is
more difficult. With a pier that is not level, each
adjustment in azimuth also causes a minor shift in
altitude and vice versa. This is why we have
included the bubble level on the
Mach1GTO .
Keep in mind that unless you are a serious
astrophotographer or imager, “perfect” polar
alignment is not critical.
We recommend that you do your rough polar
alignment with the mount only since you will be
making major adjustments to the position of the mount at this time. The remainder of the equipment: telescope, finder,
camera or eyepiece and counterweights will add considerable weight and require more hand effort to make the adjustments.
Later, you will do your final polar alignment with the telescope and counterweights attached, but the adjustments will be
small.
Note: The illustrations below show only the RA axis. This was done for clarity since the declination axis blocks the view into
the P
OLAR
F
ORK
B
ASE
. You will, of course, be doing your rough alignment with the mount assembled.
1. If the Polar Scope (PASILL4 or earlier model) is installed, you may remove it to complete these steps.
2. Remove the P
OLAR
S
COPE
C
AP
(unless a polar scope was installed). If you examine the polar axis assembly, you
will see that the center of the R.A. shaft is hollow. Additionally, if you look at the dec axis, you will see that it has a
sliding cover (the S
IGHT
H
OLE
/ C
ABLE
A
CCESS
C
OVER
). By sliding this cover to the “open” position, you open a sight
line through the RA axis and out into the sky. For your rough alignment, you will peer through this sight tube and
attempt to center Polaris.
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