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POLAR ALIGNMENT OPTIONS – FINE POLAR ALIGNMENT
For very casual visual observation, you may skip this section and simply start observing. A finder-scope or single power
finder may be required to locate objects since GoTo slews with the keypad require good polar alignment for spot-on
accuracy. Don’t forget to tighten your Altitude Lock Knobs (4) before you begin! For casual visual observation, you can
move the telescope manually via the clutches or by using the GoTo and centering functions of the keypad.
The keypad and GTO Servo Control Box will function as soon as they are plugged in. That means that the R.A. axis will be
moving westward at the sidereal rate. Note, however, that this motion will not be accurate enough to qualify as “tracking”
without accurate polar alignment. In short, if you will depend on the GoTo functions of the 1100GTO, or if you intend to do
astrophotography, you must perform a more accurate polar alignment. Some methods, procedures and tips are presented
below. You will complete this alignment when your scope and other equipment are mounted.
Methods for fine polar alignment
●
Polar Alignment Scope
– Our optional Right-Angle Polar Alignment Scope (RAPAS) will allow you to quickly align
your mount on the pole. The reticles are 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 polar
alignment scope, please read the instructions sheets that come with it. If you are planning long-exposure astro-
imaging, we suggest that you use the polar alignment scope, then tweak the final polar alignment by using traditional
drift alignment, the GTO Quick Star-Drift Method (refer to the Keypad v4.19.3 manual),
PEMPro
™ Pole Align Wizard
or other similar alignment program.
●
GTO Keypad
– Please refer to the instruction manual for the GTO Keypad and read the sections from “Getting
Started” through “Alternate Polar Calibration Routines & Tips.” As time goes on, the keypad manuals will be updated.
Please refer to the Technical Support section of the website for the most recent documentation. Here are summary
descriptions of several techniques for polar alignment from the current Keypad Manual available on the Technical
Support page of our website.
○
The Keypad startup routine provides two methods: The North Polar Calibrate and the Two Star Calibrate.
These two polar alignment methods, though no longer recommended, were designed for quick and coarse
alignment in the field with portable setups. They are for visual observers, not imagers. The Two Star Method
is the better of the two as it is less affected by the extremely low resolution in R.A. near the pole and by
orthogonality issues.
○
The Daytime Routine (see “Polar Aligning in the Daytime” in the Keypad Manual), is a great trick for daytime
setup. It will allow you to “wow” your friends by setting up and finding planets and bright stars in the daytime.
In addition, it is the recommended first step in alignment for anyone in the southern hemisphere. Even those
in the south who own our polar scope will find it helpful, since it will generally put the rather difficult-to-spot
southern stars into the polar scope’s field of view.
○
The GTO Quick Star Drift Method is for use with a finder scope. By using a finder scope, you are able to
remove orthogonality issues from the process, making subsequent alignments much easier.
Using the Daytime Routine, followed by the GTO Quick Star Drift Method, will provide accurate enough
polar alignment for extensive imaging. This combination is our recommended procedure for anyone in the
southern hemisphere, or anyone who finds their view of the pole obstructed.
●
Computer Software Solutions
○
Polar Align via PEMPro’s “Pole Align Wizard” – PEMPro
™
is a software by Ray Gralak and distributed by
CCDware. This powerful application not only analyzes and improves the periodic error performance of any
mount that is equipped with a CCD camera and compatible camera control software, but also includes “Pole
Align Wizard”.
“Pole Align Wizard” is one of the best method of accurately polar aligning! It is like traditional drift aligning,
but on steroids! It has the advantage of automatically choosing the optimized stars for drift aligning and does
not have to worry about star magnitude since the CCD can see dimmer than an eye. Also, it compensates for
air refraction and other variables that manual drift aligning cannot. It does require the use of a CCD camera
and corresponding camera control software. The Wizard walks you through the alignment process with easy
step-by-step instructions.
Note: This and the R.A. Correction Method (on the Technical Support page
of our website) are the preferred alignment method when tweaking the RAPAS orthogonality.
A full PEMPro
™
edition is included with the 1100GTO, 1600GTO and 3600GTO mounts (sorry, not the
Mach1GTO
).