Polar Alignment

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 or Southern 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 in astrophotography than in occasional stargazing.

Daytime alignment

Aim at a Pole Star method

Northern 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 the angular distance. This is useful in any type of polar alignment, but specially in drift

Auto 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


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]

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