⦁ If the star drifts South the telescope’s polar axis is pointing too far East. Note the direction of the star’s drift in Declination (disregard drift in Right Ascension as this is probably due to periodic error of the drive): Practice moving the scope back and forth in declination so that you know which direction if north and south in the eyepiece.ģ. Pointing the telescope at a star that is straight up, with the Declination set to 0°, will point the telescope in the right direction. of the meridian and within ±5° of the celestial equator. For best results, the star should be located within ☓0 minutes in R.A. Point the telescope, with the telescope's drive running, at a moderately bright star more or less overhead, where the meridian (the North-South line passing through your local zenith) and the celestial equator intersect. Place the eyepiece (or eyepiece/focal extender combination) into the eyepiece holder of the telescope.Ģ. Here are the steps for Drift Method Polar Alignment (note that this works if you can find the pole star in the sky or not, and works in Northern or Southern hemispheres). Using a 2X or 3X Focal Extender lens will help speed up the process. The right ascension axis has bearings below the T-joint, that is, it is not supported above the declination axis.ĭrift alignment requires the use of a high power eyepiece, preferably with an illuminated crosshair, or you can defocus a bright star so that the out of focus star nearly touches the edges of the eyepiece field of view. The telescope is placed on one end of the declination axis (top left in image), and a suitable counterweight on other end of it (bottom right). The task of tracking objects across the sky was solved by telescope designers in the early 1800's, most notably by British astronomical instrument maker Edward Troughton with the 3-inch " Troughton Equatorial Telescope" that was finished in 1795, and the German optician and telescope maker Joseph von Fraunhofer with his " Great 9-inch Dorpat Refractor" that was finished in 1824.
But this did not solve the problem of steadily tracking celestial objects as they rose in the east, making an arc across the sky, and set in the west. Astrophotographers, and those who want the best GOTO pointing performance from their mount should consider the Drift Method.īy the late 1700's, most mountings that could hold telescopes in steady position were largely of the type that could rise up and down (the altitude movement), and/or could be moved from side-to-side (the azimuth movement). While there are several options for getting precision polar alignment, few beat the Drift Method because by watching a star drift, you are compensating not only pointing the polar axis of your equatorial mount, you also are getting the benefit of compensating for flexure of the mount/telescope combination.
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