Hello folks,
I’ve seen many of you struggle with polar alignment and having a really hard time. And since polar alignment is really important to produce long exposure shots, I want to share my easy method of polar alignment. This method takes me less than 5 minutes to perfectly polar align.
This method only works on all polar scopes which have built-in full view crosshairs and a fine scale for polar alignment. Like for example the Star Adventurer – or generally all new SkyWatcher polar scopes. I’m pretty sure other mounts and manufacturers also provide this kind of polar scope markings, but don’t quote me on that.
Since this method relies on Polaris, this only works in the Northern hemisphere.
I will explain and show you the method based on the modern SkyWatcher polar scopes since those are the ones I am most familiar with.
Update 2018-07-09: To show you that this really works, this is a Guiding Assistant run of PHD2 which measured the Polar Alignment error. This was done with my method:
Prerequisites
- Polar scope with crosshairs and fine adjustment circle
- Polar scope should be aligned properly
- App that shows you where Polaris is at the current date, time and long/latitude
Step 1: Align and level your mount
Well that’s an easy one. Align the mount roughly towards Polaris, you don’t want to move it after you have leveled it. Then, level it.
While you technically don’t always need to level your mount perfectly, for this routine this is necessary. So, bring it up to level as close as you see fit. It does not need to be perfect but as close as possible is good enough.
Bring Polaris anywhere inside the viewport using the Alt and AZ knobs on your mount.
Step 2: Center Polaris in the Crosshairs
Now we begin the polar alignment routine. Center Polaris inside the cross hair of your polar scope using the Alt and Azimuth knobs on your equatorial base. Your result should look like this.
Step 3: Move Polaris outside the circle
While that might sound counterproductive you have now to use either Altitude or Azimuth knobs to move Polaris outside the circle. We do this to align the polar circle perfectly horizontal in the next step. Move it approximate double the distance from the center of the circle. It’s important that you only touch one set of polar alignment knobs, not both!
Step 4: Align the RA axis and the polar scope
Now you have to rotate the right ascension axis until one of the lines is on Polaris itself. By doing this you ensure that the polar scope display is perfectly aligned and the crosshair is leveled.
Rotate the axis until it looks like this.
Step 5: Use the app to find Polaris correct position and align
Now open the app on your smartphone and wait until it gets its GPS signal. It will update to the current location and will show you exactly where Polaris is supposed to be on the polar scope. If the display doesn’t correspond to your polar scope type, change it in the settings. It will look for example something like this.
Now since your polar scope is perfectly aligned just go ahead and use the Alt and AZ knobs on your mount to move Polaris to the exact position the app shows you.
And that’s it. If you did it right and were accurate aligning Polaris inside the Polar Scope you will have easily sub 5 minutes of arc polar alignment done by eye only.
Hope it works well for you!
Clear skies
This is great. I’ve recently got a star adventurer and while i’ve done ok (120sec subs at 200mm), i felt i could do better if i could accurately line up the crosshair. Until now i’ve biased the weight while aligning so that gravity pulls the counterweight bar down to bottom center.
Another handy tip: once aligned, carefully rotate the RA axis and make sure polaris doesn’t stray as the circle moves around.
Thank you very much. This is exactly what I have been looking for: a simple and precise guide with illustrations matching exactly what I see in my polar scope. Extremely helpful.