Polar alignment using apps

[Fenris]

Hello, newbee talking.

I'm getting ready to buy my first mount, and have been thinking about polar alignment. I'm buying the SW star adventurer, mainly to use for imaging without a telescope (both wide-field and DSO). The biggest problem with this mount as far as i know is that i can't check alignment while imaging. So on to the point:

I was thinking buying that Polar Align app by Varros, to be as accurate as possible and hopefully not need to check alignment all the time. But that app is using the coordinates from my phone. Is that anything to trust? My previous phone had a margin of error on the GPS at 3000 m!!! My new one is probably better (Samsung galaxy s3) but do anyone have any experience with this app on phone as to accuracy? No point in buying the app if the GPS it will be using is Rubbish...

Oh, and as far as i understand the polar scope on the SW SA is inverted or mirrored (don't understand the difference). How does this affect the alignment procedure? And can i check if it is or not (some say it is N-S AND E-W, others say it's only N-S). I have read everything i can find, an as far as i understand it goes like this: if the app say Polaris should go at six o'clock in the polar scope, i should actually put it at twelve o'clock with a N-S inverted scope. So, up is down and/or left is right?

FYI, i have never done an alignment before. EVER. Or owned a mount or telescope...

[D4N]

If the accuracy of the position was only 3000m when the phone has a clear view of the sky then it wasn't GPS, that will simply have been based of cell tower locations.

Even a very poor gps position should be within 100m but more often than not it will be within 10m.

Try pointing the polar scope at a tree and see if it is upside down or not.

/Dan

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[brrttpaul]

I just use an app on my phone or on the pc , whatever it shows on the app i copy it on my SA . you can see which is the right way as it shows cassiopa on the SA and on the app so just copy whatever it shows on the app

[Fenris]

D4N, will the "pointing at tree" work to figure out E-W inversion too? I would almost assume it would...

And how much will a margin of 10-100 meters matter for the Polaris position and tracking accuracy? I wouldn't expect it would have THAT much to say, would it? Of course i could do like brrttpaul and use a computer, but i rarely have it with me in the field...

[D4N]

Yes so long as you can tell the left side from the right side it should work.

100m position error will make very little difference to the position of Polaris in the sky.

/Dan

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[Waldemar]

Just download Google Earth and check your position... VERY accurate!