- Polar Alignment
Polar alignment is the act of aligning the rotational axis of a telescopes
equatorial mount in parallel with the rotational axis of the earth.There are various ways to achieve this.
Alignment Methods
The method to use differ depending on if the alignment is taking place in daylight or in night. Furthermore, the method differs if the alignment is done in the
Northern Hemisphere orSouthern Hemisphere and σ. Other things to consider are what the purpose of the alignment is. For example, the demand for accuracy is much more significant inastrophotography than in occasional stargazing.Daytime alignment
Aim at a
Pole Star methodNorthern Hemisphere
North Star Southern Hemisphere
σ Octantis the
South Star Drift Alignment
A rough alignment is performed - then refined by pointing at different stars and observing any drift that occurs. The mount is then adjusted according to the direction of the observed drift.
Northern Hemisphere
Southern Hemisphere
Equipment used in polar alignment
Crosshair Eyepiece
A
Crosshair Eyepiece is an ordinary ocular with the only difference that it has a Crosshair for aiming and measurement of theangular distance . This is useful in any type of polar alignment, but specially in driftAuto guiding systems
Dedicated Polar scope
A small telescope usually with an etched reticle that is inserted into the rotational axis of the mount.
Various problems in alignment
* Technical
**Worm gear References
See also
*
Equatorial mount
*Setting circles
*Inertial guidance system
*Tpoint
*South Star
*North Star External links
* [http://telescopes.com/faq/Polar-Alignment.html FAQ Polar Alignment]
Wikimedia Foundation. 2010.
