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Vega

Polar alignment with EP ?

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At the moment i've been using the 'lazy method' of polar alignment by using my finderscope and some charts printed from polarfinder. Obviously I make sure my polar scope is aligned to the scope first!

Anyways, I was wandering... Is it possible to use polarfinder charts with a low mag, wide-angle Eyepeice ? As in, having a FOV large enough to see the 3 - 4 surrounding stars around polaris through the main scope to accuratly find the Celestial Pole.

That way there's no need to use a second device (polar scope/finderscope) which runs the risk of not being accurately aligned with the scope itself beforehand.

Any comments ?

Matt

ps I dont do drift alignemnt due to the time it takes (plus im lazy :lol:)

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Sorry, my first post was a terrible explanation.

I usually use the finderscope to find the Celestial Pole. I do this by using a print-out like this as a guide and centre the finderscope crosshairs just as shown in the printout. I use the finderscope as it is the only thing with a wide enough FOV to visually see the 4 surrounding guide stars near polaris. This means I have to make sure the finderscope is perfectly aligned with the scope before I can try and polar align with it. Otherwise I would have a polar aligned finderscope but not a polar aligned telescope

However, having an eyepeice with a large enough FOV to see the 4 guide stars near polaris would mean I dont have to use the finderscope to polar align.

Forgot to mention this is for photography and thats why I need accuracy (but without the trouble of drift alignment method)

Hope I'm making sense :lol:

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Kind of, but if you pointed the finder and 'scope at the celestial pole, how does that make the mount pointed at the pole? You could just as easily point it at Sirius, and that would be daft.

Captain Chaos

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I rely on the fact that my finderscope is aligned well with my mount (I know, such a silly way of doing it). ie if for example I point my finderscopes crosshairs at Sirius, the view in the eyepeice will be perfectly centered on Sirius also. I then make sure the mount is level, pointed towards Polaris at 90Deg etc etc then adjust the mount by looking through the finderscope and comparing with the charts. (obviously adjustments are not made in RA or Dec, I just use the alt azm adjustment knobs stc)

Anyways... if say a 40mm Widefield EP was big enough to see all the stars as shown in those charts, it would be a much better method. At the moment I can use my 25mm EP and simply centre it on polaris (not accurate enough). The FOV in a 25mm EP is too small to be able to see the other stars near polaris in those charts to find the true NCP)

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I googled the term polar alignment for a bit and I found the Kochab clock method. Basically, you go 43 arcminutes (one and a half Moon diameters) off Polaris in the direction of Kochab.

My biggest problem with the junky EQ1 mount is that it's hard to know a) how close to 90 Declination it is set and :) whether the scope optical axis intersects the RA axis or is parallel. Surely when you are at 90 Declination and swing the scope in the RA axis, the view in the eyepiece should just rotate, not shift. I do see lots of shift but can't figure out how to cancel the misalignment. Perhaps strips of beer can within the scope rings?

I've also been trying to figure out the drift alignment method. Don't ask why since there is little chance of this scope doing any long exposure imaging. But it was good practice and I spent 3 hours chasing Saturn (as my meridian star) and then Arcturus (in the east). Without lines etched on the eyepiece, I couldn't be precise but it looked to me like I got pretty lucky with it and the bright spots stayed in the middle.

Here's my drift alignment mnemonic (CP stands for the celestial pole you can see in the sky)

Azimuth: if your meridian star appears to RISE in the scope then turn the CP end of your polar axis to the EAST

Altitude: if your EASTERN star appears to RISE, then DROP the CP end of your polar axis, if your WESTERN star appears to RISE, then RAISE the CP end of your polar axis

(this works in both hemispheres, south and north, don't know about the equator).

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