The polar finder is simply screwed into the back of the mount. Correct alignment of the mount can be achieved within a very short time with this improved polar finder. Good alignment of the mount with the North Celestial Pole can be achieved in a short time by using the polar finder. As the celestial North Pole (to which the telescope mount must be aligned) does not exactly coincide with the position of the Pole Star, using this polar finder is very important. The sighting is improved, with the precise alignment making long-term astrophotography possible. The viewfinder arrangement has been further improved, with precision alignment now possible allowing long exposure photography to be done. The Polar-Axis finder Scope enables highly accurate polar alignment of the Pro equatorial mount. Accurate polar alignment is essential for precise tracking, especially at high powers, and for astrophotographic guiding. This accessory threads into the mount's housing along the Right Ascension axis. The optics feature a printed reticle that makes aligning on Polaris easy and fast. Handy scope makes polar-aligning the Pro equatorial telescope mount a cinch. Built-in reticle pattern includes Big Dipper and a target-spot for Polaris - just place Polaris in the circle and you're mount is all set for manual or motorized tracking! Easy installation - Polar-Axis Finder Scope threads directly into mount housing along R.A. (right-ascension) axis. Quick polar-alignment gives you more time to enjoy the view at the telescope eyepiece. Ensures accurate tracking and slow-motion control for your telescope mount.