Polar Alignment of an Equatorial Mount

This (I hope) will be my really simple guide to Polar aligning an equatorial mount for either spot on viewing sessions or for the essential need for any Astrophotography set-up. Polar aligning is one of the hardest parts of our fantastic hobby to learn but there is absolutely no reason why it should be. As we all know, all seasoned amateur astronomers want to help anyone who is new to the hobby and to pass on their hard earned knowledge to the next “generation” of astronomers. This is all well and good - but most of these “seasoned astronomers” also have absolutely no idea on how to get a point across without making it sound too technical, or by using big words that confuse the hell out of someone who is new to the hobby. Words like - equatorial, ecliptic, RA (right ascension), DEC (declination), Alt-Az (altitude & azimuth) are taken for granted once they are known, but we all forget pretty soon how confusing these words are when we are taking our first tentative steps in astronomy. Put this alongside the complicated looking equatorial mount itself, and all this takes me back to my first month or two in the hobby. And this is the sole reason that I conceived this website and am now writing this article - to hopefully and in the simplest way that I can, help normal people to understand Polar alignment. I will use the technical words because you need to know them, but I will explain what these words mean. And lastly, this article is not meant to be condescending, I am simply trying to make what a lot of people find confusing - less confusing.
1: Level Tripod This is one of the most important things that you will do. If you do not have a level tripod, you will not have a level mount, which in turn means that you will not get Polar aligned. LEVEL YOUR TRIPOD. Most mount heads and tripods have a built bubble level, if not buy a cheap spirit level and make sure that your tripod is level across each leg direction. Ensure that one of the legs is pointing north toward Polaris. It is always best to do this before you install the mount head as all tripods have a nice flat surface. 2: Equipment Once you have made sure that your tripod is nice and level you can now screw in the mount head. Ensure that you have it set up correctly and it is all roughly pointing north. Attach the mount head to your level tripod then attach your telescope, finder scope/red-dot-finder and eyepiece/camera. Check that your mount is still level. 3: What is Polar Alignment? The Earth rotates, this is why the stars appear to move across the sky. What we need to do is to counteract this rotation. An equatorial mount will track an object as it appears to move across the sky (Right Ascension), it does this by tracking in the opposite direction to the Earth’s spin so as to keep the object in the eyepiece/camera. But, for it to be able to do this it needs to be Polar aligned. Polar alignment is really simple - the Polar Axis needs to be pointing towards one of the poles (Hemisphere dependant).
© Paul’s Astrophotography 2020 South                          North
4: Polar Align As I am in the Northern Hemisphere I will be referencing the north (sorry south). In the north we are lucky as we have a star that is very, very near to representing north and this star is called Polaris or the north star. You basically need to line the axis marked in red in the above image with the star Polaris, this axis is where the Polar scope is situated. Use a mobile phone app to find Polaris or use the 2 “pointer” stars in the Big Dipper Constellation to find the star. Now follow these 2 simple points to get polar aligned:
From now on you will not use the altitude or azimuth knobs as all scope movement will be controlled through either the handset and motors on a GoTo or by loosening the RA and DEC knobs and moving the scope manually. A good friend of mine has put together a guide on drift aligning which is a method he uses to fine tune his polar alignment. It takes a bit longer but is definitely worth the results if you have a GEM with just a right ascension motor, his guide can be viewed here Drift Alignment Guide .
1) Get Polaris in the polar scopes field of view. You do this by moving your mount left or right with the Azimuth Knobs, and up and down using the altitude levers. If you have an illuminated polar scope turn on the red light, if not shine a (not too bright) red light across the polar scopes exit hole. You should see just the one star and this will be Polaris. 2) Now you need to place Polaris in the correct position on the Polar clock. Polaris is not situated dead North, instead it rotates in a tiny circle around the true point of North. By placing Polaris on the correct place on the clock means that the mount is accurately aligned. Using an app (Below Right image), find out where Polaris should be on the polar clock for your location & time. You will need to adjust the Azimuth & altitude knobs (middle right image) while looking through the polar scope, you will see Polaris moving about as you twiddle the knobs. Place Polaris in the position that the app tells you. When Polaris is at the correct place on the clock you are Polar aligned.
LEFT - RIGHT Galaxies Nebulae Narrowband Solar System Stars