Polar Alignment in Several Easy Steps

Developed by Fr. Lucian J Kemble, OFM and Dr. Peter Bergbusch - 1975
Page last updated: - 2000-01-23

Polar Alignment of a Telescope on Equatorial Mount

Fr. Lucian J. Kemble, OFM

Preliminary remarks:

I know I sometimes tend to get long-winded, so I will try to keep this as brief but as comprehensible as possible.

This method is designed for clock-driven Fork or German mounts and might not be of much use for Poncet or so-called barn-door types.

This method is designed for telescopes fitted with fairly large and accurate setting circles. It will be useless on small, badly-functional types, and I have no experience with automated or electronic circles

VERY IMPORTANT: The telescope tube must be aligned with the mount's polar axis, so that the SCOPE and AXIS point in such a way that when the scope is pointed at the North Celestial Pole or [NCP] then the Dec. circle itself will read +90. I will not go into details of adjusting the Dec. Circle. User's manuals usually explain the procedure. Off-alignment in this feature can lead to some strange field-rotation streaks, etc., on photographs. It can also lead to sometimes fairly large mis-readings when it comes to searching for faint objects by coords alone. But the use of setting circles is another issue I won't go into here except for use in polar alignment.

The method by no means minimizes the use of other methods, e.g. the drift method which is used successfully by top-notch photographers such as John Mirtle of Calgary. I have just found it quicker, very accurate and, for my particular interests, applicable even in the daytime. It was worked out in 1975 by myself and Dr. Peter Bergbusch of Univ. of Regina. It's success was tested during the eclipse of 1979 at Estevan, and successful, steady photography and movie of the event were achieved with several scopes. Dennis di Cicco gave an abbreviated description of a similar method in Sky and Telescope magazine, Dec/86, p.570, using different reference stars. I will append the reference stars' coords at the end of this explanation.

All coordinates used are those for 2000.0, since we are close enough to that standard epoch. Originally I had to work out the coordinates, local sidereal time, etc. by hand, later from The Astronomical Almanac and now from a computer programs such as ECU. Invaluable experience.

Principle behind the method:

The principle involved relies on the positions of four fairly bright stars, one or two of which is always in one's observable sky near the Celestial Equator: two of them along or very near the hour-line joining Polaris and the true NCP; the other two on the hour-lines at right angles to this line. Since Polaris is at RA 02 31 50 the reference stars I use are then roughly on the Equator at the ~2.5, 8.5, 14.5 and 20.5 hour lines.

Keep in mind that the mount moves in Azimuth and Altitude; the scope in Right Ascension and Declination.


  1. Scope on mount and leveled tripod or pier, positioned in Azimuth and Altitude such that the RA axis is roughly pointing towards Polaris.

  2. Scope, preferably without diagonal, with medium power eyepiece pointed visually to one of the four reference stars closest to meridian; locked in RA and Dec.

  3. RA setting circle adjusted to correct RA of the reference star. Ignore Dec for the moment.

  4. Using ONLY RA and Dec circle readings, the scope is set to correct RA and Dec of Polaris. Locked on.

  5. Mount or wedge only is now moved in Azimuth and Altitude until Polaris is found and centered in finder. IMPORTANT: do NOT use RA and Dec slow motion controls for this part of procedure. Just move the whole assembly of wedge and tripod.

  6. Scope returned freely to center the reference star again and locked on. RA setting circle again re-adjusted to correct RA of this star, again ignoring Dec reading.

  7. Steps 4 and 5 repeated and, if further minor adjustments are necessary, step 6 is repeated, using a higher power eyepiece.

  8. Check accuracy. By now Polaris should easily be found in the eyepiece, using RA and Dec settings alone. For greater refinement, using ONLY RA and Dec coords , not using slow motion controls nor finder, seek out several other bright stars, preferably to the East or West of the meridian and equator.

With practice, the whole procedure can be done in about 5 to 10 minutes. When looking for an elusive deep-sky object, use a low power eyepiece first. If the polar alignment has been properly done, the object should be in the field of the eyepiece. I have most often achieved a 15' accuracy or better anywhere in the visible sky. I am fortunate in having a solid pier, a Byers Mount with its huge, accurate circles [with a hand-made vernier my Dec circle is accurate to within 15"], and a very accurate alignment, I seldom use my 12x80 finder, as I've often mentioned. Great, great fun..


With this method I have had great success with piggy-back shots, using anything from a 50mm to a 210mm lens, for as much as 10 minutes' exposure. I have even had some good 5-minute, unguided shots through prime focus or with a focal reducer. There are, of course, limitations, e.g. longer exposure on very high power, where some kind of guiding is necessary.

Daytime Set-up for Observing:

Since, in step #1, Polaris cannot be seen [yet] just aim the mount and scope as best you can, from known daytime true North in Azimuth and Altitude. Use the CURRENT Sun's accurate position in RA and Dec, [and then Venus, if visible] for steps #2,3,4,5. With care and luck you should even see Polaris and several other bright stars, refining the setting of RA each time. With daytime set-up I have seen so many wonderful things, e.g. Venus near superior conjunction only 2.5 degrees from the Sun, Mercury and all the other bright planets. Saturn only 12 degrees away at the time Voyager II was passing by, all the bright stars of the Pleiades, all four components of the 'Double-Double', Epsilon Lyrae, faintest at 6 mag, etc.; Hyakutake and Hale-Bopp within minutes of sunrise or sunset. Great, great fun.

On a final note. I have used Vega as a test star so many times as a check after a good polar alignment in the daytime that I know its coords by heart. So that when, in the movie "Contact", I heard the heroine read off the coords of her target star on the radio, I knew exactly what that star was. Great, great fun...

Reference Stars:

In the 20+ years that I have used the method described above, celestial coords have changed considerably, especially Polaris. When I began I used the then-common 1950 coords and some calculation to find current coords. This even involved determining the exact sidereal time, using data from the annual Astronomical Almanac. Great, great fun. I have a list of a number of good reference stars for the current epoch stuck to my observatory wall, from either the RASC Handbook list of bright stars, or the current Astronomical Almanac, or ECU, or MegaStar, or ECU.

Here, then, are the reference stars I use - all for 2000.0

Alpha UMi [Polaris] 02 31 50.5 +89 15 51
Xi 1[65] Cet 02 12 59.9 +08 50 48
Beta Cnc 08 16 30.9 +09 11 08
Alpha Boo [Arcturus] 14 15 39.6 +19 10 57
Theta Aql 20 11 18.2 - 00 49 17
Also Delta Ori 05 32 00.3 - 00 17 57

For me this is just a tool to enable better observing and photography. I do hope some of you may find it useful and it is with that expectation and the joy of sharing the wonderful night and daytime skies with you that I present it.

Respectfully submitted, and good luck. Lamplighter

Fr. Lucian J. Kemble, OFM - Biographical details

Fr. Lucian was born in 1922 on a small farm in southern Alberta. After spending four years during WW2 as a radio operator, he entered the Franciscan Friars in 1946. Ordained in 1953 after 7 years' study in Philosophy and Theology, he spent almost all of his priestly life in teaching and preaching. A member of the RASC for over 27 years, he worked with a Celestron 11 on Byers Mount in a shelter at St. Michael's Retreat, Lumsden, Saskatchewan. His main interest in astronomy was searching out deep-sky objects, of which he had over 5550 observed, drawn and noted on file. His other main interests were photography, music and reading. Lucian passed away on February 26, 1999. He is sadly missed.