Anyone who owns an equatorial mount knows about polar alignments. If you’re not familiar with the concept I’ll explain it here. Polar aligning a telescope mount consists of very precisely adjusting the azimuth and altitude of your Right Ascension (RA) axis. The purpose of this adjustment is to allow the RA axis of your mount to correctly counteract the rotation of the Earth when tracking objects in the night sky. If your RA axis is adjusted too far East or too far West, then stars will gradually drift out of the field of view. If you are doing astrophotography, the stars drifting action will cause them to look more like eggs, or in extreme cases, lines.
If you’re reading this post, but have not read about how to eliminate friction in an equatorial mount, be sure to go back and read that post as well as watch the video. As long as you have friction in your system, the process I’m about to go over will be difficult for you to do.
This portion of the blog will focus on getting as accurate of a polar alignment as possible. Because polar alignment is such an important step in setting up for imaging, or a long night of visual observations, I’m going to break up the process into a few discrete, but very detailed steps. Mastering each step in order will make polar alignment almost trivial.
Because the very first thing anyone does when setting up their telescope is laying out the tripod, it makes sense that my polar alignment series starts there too. Most people don’t scrutinize the placement of their tripods as much as I do, but I make sure that the leading leg is as close to true North as I can measure. This helps me out because I have markings that I use on the tripod and mount to ensure that if I can get the leading leg of the tripod facing North, then the rest of the equatorial mount can be rough polar aligned before the first stars are visible. Being that this is the first step in the process, it does carry a margin of error, but that margin is corrected for in later steps. A realistic goal is to be able to get the tripod within one degree of True North consistently. That will come after you have some practice.