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How to Use a Refractor Telescope With an Equatorial Mount

An equatorial mount lets you navigate the night sky with your refractor telescope using the celestial coordinate system. You also can use an equatorial mount to take long-exposure photographs of faint deep sky objects, such as galaxies, nebulae and star clusters. To work properly, an equatorial mount must be aligned with Polaris, more commonly known as the North Star. Polaris marks the celestial North Pole. The North Star remains stationary throughout the night, and all the other stars in the sky rotate counter-clockwise around it.

Things You'll Need

Planisphere
Refractor telescope
Equatorial mount
Counterweight
Magnifying eyepiece

Instructions

- 1
  Locate the Big Dipper constellation in the northern sky. You will use it to find Polaris, the North Star. The Big Dipper consists of seven bright stars arranged in the shape of a ladle. Use a planisphere to determine the Big Dipper's present location if you have difficulty finding it. Identify the two stars that form the outer edge of the Big Dipper's bowl. Draw an imaginary line from the bottom star, through the top star and beyond the Big Dipper's bowl to the last star in the handle of the Little Dipper. The star at the end of the Little Dipper's handle is Polaris, the North Star.
- 2
  Lay the equatorial mount flat on the ground. Extend each of its tripod legs to the same length, and tighten the thumbscrews on each leg to lock it in place. Stand the mount upright. Turn the mount so that the leg directly beneath the counterweight mounting bar--the long, metal rod extending from the mount's polar axis--points towards Polaris.
- 3
  Release the mount's latitude lever. Use the latitude scale on the side of the mount to tilt its polar axis to the same latitude as your viewing location. For example, if the observing site is at latitude 40 degrees North, the latitude scale should read "40." Consult a road map or atlas if unsure of your observing site's latitude. Tighten the latitude lever after entering your observing latitude.
- 4
  Position your head next to the mount's polar axis and look in the direction of Polaris. Verify that the polar axis is pointed directly at the North Star. Alternatively, if your mount features a built-in polar alignment scope, look through the scope and confirm that Polaris appears in the center of its field of view.
- 5
  Attach the counterweight to the counterweight mounting bar. Use a counterweight equal to the weight of your refractor telescope. Insert the telescope's mounting bracket into the mount and tighten the locking screws to secure the telescope to the mount.
- 6
  Use the right-ascension and declination slow-motion knobs on the mount to aim the telescope at an astronomical object. Use the right-ascension slow-motion knob to track the object as it changes position throughout the night.

Astronomy