Polar Alignment

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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.

Contents 1 Alignment Metods 1.1 Daytime alignment 1.2 Aim at a Pole Star method 1.2.1 Northern Hemisphere 1.2.2 Southern Hemisphere 1.3 Drift Alignment 1.3.1 Northern Hemisphere 1.3.2 Southern Hemisphere 2 Equipment used in polar alignment 2.1 Crosshair Eyepiece 2.2 Auto guiding systems 2.3 Dedicated Polar scope 3 Various problems in alignment 4 References 5 See also 6 External links

[edit] Alignment Metods

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.

[edit] Daytime alignment

[edit] Aim at a Pole Star method

[edit] Northern Hemisphere

North Star

[edit] Southern Hemisphere

σ Octantis the South Star

[edit] 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.

[edit] Northern Hemisphere

[edit] Southern Hemisphere

[edit] Equipment used in polar alignment

[edit] 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

[edit] Auto guiding systems

[edit] Dedicated Polar scope

A small telescope usually with an etched reticle that is inserted into the rotational axis of the mount.

[edit] Various problems in alignment

• Technical
  • Worm gear

[edit] References

[edit] See also

• Equatorial mount
• Setting circles
• Inertial guidance system
• Tpoint
• South Star
• North Star

[edit] External links

• FAQ Polar Alignment