Methods for fine polar alignment
•
Polar Alignment Scope
– Use our optional polar scope (PASILL4 or PASILL3 (prior version) models – earlier polar
alignment scopes cannot be used as effectively with the
Mach1GTO
as explained later in this section). This will allow
you to quickly align your mount on the pole stars. The reticle was designed for use in both the Northern and Southern
hemispheres. Even users of the GTO computerized mounts will find these polar scopes useful, particularly if your
telescope is not orthogonal to the mount (please refer to the keypad manual for a discussion of orthogonality). If you
have a PASILL4 or PASILL3, please read the instructions sheets that came with it with the following modification:
The reason that the
Mach1GTO
requires either the PASILL4
or PASILL3, is that these polar scopes have reticle housings
that turn freely in their collars. Unlike all the other mounts
that we have produced since the early 1990’s, the
Mach1GTO
’s polar axis shaft does not reach all the way to
the bottom of the polar axis housing. With these other
mounts, the polar scope was actually screwed into the end of
the polar axis shaft. If you turned the polar (RA) axis, the
polar scope turned as well. With the
Mach1GTO
, the polar
scope attaches to the P
OLAR
S
COPE
A
DAPTER
, which is in turn,
attached to the polar axis housing, not the polar shaft.
Turning the polar axis does NOT also turn the polar scope.
To use the polar scope with your
Mach1GTO
, simply turn the
polar scope’s reticle housing instead of the RA axis as
instructed during the final stages of polar alignment. If you
started with the reticle properly oriented these will be small
movements.
It is possible to use an older model polar scope (PASILL or
PASILL2), but they may be a bit less accurate. To use one of
these earlier polar scopes, screw the unit into the adapter,
and then back it off to align Polaris’ relative position to the
pole. Proceed normally turning the polar scope wherever the
instructions say to turn the RA axis. Since the scope won’t be
screwed in tight, you may have a bit of sag that will slightly
reduce your accuracy.
•
GTO Keypad
– Please refer to the instruction manual for the GTO Servo Drive and read the section describing the
startup sequence. For daytime setup, read the section entitled “Polar Aligning in the Daytime” in the GTO Keypad
manual.
•
Star Drift method
– Traditionally, this has been regarded as the most accurate method of polar alignment, however it
is also the most time consuming. If you are planning long exposure astrophotos, we suggest that you use the Polar
Alignment Scope (see above), then tweak the final polar alignment by star drifting. Refer to the GTO Keypad manual
for hints on polar aligning using a GTO Quick Star Drift method. Also refer to the Technical Support section of our
website for further information. For general information regarding traditional star drift alignment, please refer to the
recommended reading list at the end of this manual.
Altitude and Azimuth Adjustments
1. Loosen the A
LTITUDE
L
OCKING
L
EVER
and barely loosen the two A
ZIMUTH
L
OCK
K
NOBS
. When adjusting azimuth,
remember that you must back off with one A
ZIMUTH
A
DJUSTER
K
NOB
to move the other.
2. Follow one of the methods of fine polar alignment mentioned above.
3. When polar alignment has been achieved, tighten the A
LTITUDE
L
OCK
L
EVER
. Make sure that the A
ZIMUTH
A
DJUSTER
K
NOB
that you have been backing off is turned back in until it is against the A
ZIMUTH
A
DJUSTING
P
IN
so
that the mount is held firmly in azimuth. Tighten the A
ZIMUTH
L
OCK
K
NOBS
.
4. For a portable installation, the A
LTITUDE
L
OCKING
L
EVER
and the A
ZIMUTH
A
DJUSTER
K
NOBS
do not need excessive
tightening. You can tighten with more force for a permanent installation.
15
Summary of Contents for Mach1GTO
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