Polar Scope – how to use one
A beginners guide to using a Polar Scope for Polar alignment. This only applies to those of us in the Northern Hemisphere who can see Polaris!
Polar alignment using a Polar scope requires you to have visual sight of Polaris and to know here it is! You will notice that at most northern latitudes, you will be required to kneel down to get a visual view of Polaris through your mount’s axis, where the Polar scope is fitted, and sometimes this may not work for you due the the positioning of the declination adjustment bolts.
Polar Scope – Step 1
You need to know where Polaris is in the night sky – roughly align your mount as discussed in the previous Polar Alignment post having first followed all the tips in that post. A green laser pen can be a very useful guide if shone up the polar alignment axis to help with rough aligment but be very careful never to point one at people or planes (they may even be illegal where you are so check first).
For some mounts you now need to rotate the declination axis by 90 degrees to open up the polar alignment view, if you can’t see anything that will be why (yes it got me first time!).
Polar Scope – Step 2
Polaris is not quite at the northern celestial pole (NCP), it is a few degrees off and rotates around the NCP all the time so to accurately align you need to know where at your time and location it is positioned to align to it.
I recommend a popular phone app called PS Align Pro (only on Apple, no Android version ) as per the picture on the left – this useful app will tell you, based on your location, exactly where you should expect to find Polaris as it rotates around the NCP. It can also be used to do a pretty good rough daytime polar align by fixing your phone to the mount!
If your have an Android phone there are some other apps on Google play that do the same thing – I have used PolarAligner Pro if that helps though it is not an endorsement!
Polar Scope -Step 3
The best Polar Scopes are illuminated, its very hard to align Polaris accuratey without being able to see when it is centered.
You now need to rotate your polar scope so that Polaris matches the exact position given to you by the phone app display. You are now ready to align the mount by matching Polaris with the finder scope Polaris…
Next adjust your mounts azimouth adjustment knobs (moves mount left to right) until Polaris appears in the same horizontal plane that was displayed in the app.
Now go back to your altitude adjustment bolts (moves mount up and down) so that Polaris matches as near as you can.
You are now Polar aligned.
Now make sure you have gently tightened the azimouth and altitude bolts – tighten these just enough, do not over tighten as you will move the alignment and have to redo it.
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