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err hope its not a silly question


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ok so when i set up and do star aglinment iget the target star in the finder scope and then centralise the star in the main scope, I normally use a 25mm EP, I then ensure the star is centred in the finderscope once more

The I go to the second star and center it in the finderscope expecting it to be spot on in the EP and often whilst its close its not always spot on, I think its because im judging the centre point in the EP incorrectly - am I using the right EP for aglinment and can i get an EP with cross hairs on it so I do get it spot on ?

Kit in Sig

Thanks in advance

regards

John B

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Doing an initial alignment with a 25mm ep is fine - you'll need the wider field to find the star anyway. However - if you are off center even a tiny smidgeon then the moment you pop a higher power (eg 12mm) in, the object will be even more off center and maybe even totally out of the eye piece.

What I do to refine the alignment is use repeatedly higher powers to re-align the ota and finder. So I'll start with 24mm then refine with a 16mm then go down to 12mm and refine further. I use a zoom ep which makes it a lot easier than popping ep's in out all the time.

Hope that helps :(

Edited by brantuk
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Unless there is a previous step to the action you describe the second star will not be central, maybe not in view.

The first star is simply a start point, it means little to the scope, just that if the first star is as specified and if the scope is level and if you have the exact lat and long and time then the second star should be where it guesses it is.

If the little bits you have wrong add up to more then the field of view of the eyepiece in the system then the second star will not be in view.

Look at it in the extreme case. You enter the lat, long, time, exactly. You centre the first star exactly. The scope is hanging upside down from a tree. The scope will go to where it thinks the second star is immaterial of the scope being upside down.

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Well, I should qualify that with I use it when I'm observing and using the handset (which is rare).

I try and avoid putting an EP in altogether when I'm imaging - I use PHD and my QHY5 to get the approximate alignment and then use the crosshairs in APT with liveview on my 450D to centre to scope for alignment with EQMOD.

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Unless there is a previous step to the action you describe the second star will not be central, maybe not in view.

The first star is simply a start point, it means little to the scope, just that if the first star is as specified and if the scope is level and if you have the exact lat and long and time then the second star should be where it guesses it is.

If the little bits you have wrong add up to more then the field of view of the eyepiece in the system then the second star will not be in view.

Look at it in the extreme case. You enter the lat, long, time, exactly. You centre the first star exactly. The scope is hanging upside down from a tree. The scope will go to where it thinks the second star is immaterial of the scope being upside down.

I never hang my scope in the tree. Far too dangerous. And it would get in the way of my birdy feeders..:o

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