Polar Scope?...

[Plumb71]

Hi all probably another stupid question, do i need a Polar Scope? Or is it just as good using my finder scope? My equipment is a Skywatcher Explorer 150p on a EQ3-2 mount

Thanks

[Ronclarke]

You do need one if you intend to image but as long as it's as near as possible that will be OK for visual work..

Ron

[Ouroboros]

If you're only planning to use the scope for general observing the Moon, Sun and stars I would say you don't need a polar scope.  A polar scope is used to obtain good alignment with the earth's axis in order to do long exposure astrophotography.

The finder scope is used literally to aid finding the objects you're interested in. It helps because it is of lower magnification than the main scope so allows you to see a wider area of the sky.  It's lined up with your main scope so by centring the object up in the finder scope, you should see it when you look through the main scope. 

I used a mount similar to yours, in fact I've still got it, for some while without a polar scope just for observing. It was fine. I bought one eventually to do some astrophotography. 

PS there are ways to use a finder scope and camera to polar align, but that's a separate story. 

Edit: sorry, I'm repeating what Ron posted. 

Edited August 10, 2019 by Ouroboros

[Plumb71]

Thanks for your replies, i am at the moment not that interested in the photography side yet, i still too eager to try and see everything at once, and will probably be like that for sometime

[Ouroboros]

23 hours ago, Plumb71 said:

Thanks for your replies, i am at the moment not that interested in the photography side yet, i still too eager to try and see everything at once, and will probably be like that for sometime

OK.  Good luck and have fun with your scope. 🙂 

[wrvond]

I have polar alignment scopes in two of my GEMs but don't use them. For visual, simply aligning the mount on true North and setting your latitude on the elevation guide is (essentially) the same as performing a polar alignment.

I will grant that if you are using tracking motors a good polar alignment with the scope will yield better results, but if you are using GoTo, performing a three (or more) star alignment will eliminate any error.

[Ouroboros]

On 13 August 2019 at 15:35, wrvond said:

I have polar alignment scopes in two of my GEMs but don't use them. For visual, simply aligning the mount on true North and setting your latitude on the elevation guide is (essentially) the same as performing a polar alignment.

I will grant that if you are using tracking motors a good polar alignment with the scope will yield better results, but if you are using GoTo, performing a three (or more) star alignment will eliminate any error.

In my pre-polar scope days I normally set up as you describe and then eyeball up through the mount's RA axis tube, whilst adjusting elevation and latitude, until Polaris was more or less centred.  That gets the mount polar aligned to a bit less than 1° of the celestial pole.