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Polar Scope Alignment AVX

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#1 midwestastronomer


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Posted 04 March 2024 - 11:05 PM

Last year, I bought a polar scope for my AVX, but I read the instructions for making sure the polar scope was aligned properly, and was confused. I thought you were supposed to flip the mount 180 degrees repeatedly and keep aligning Polaris until it doesn't move out of the center of the plus when turning, but I guess that is wrong? 


I am not talking about polar aligning the scope, but actually setting up the polar scope such that polar alignment is possible. 


How is this done actually? 

Edited by midwestastronomer, 04 March 2024 - 11:06 PM.

#2 anewton81


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Posted 04 March 2024 - 11:52 PM

It's easier to do in the daytime against a distant vertical object like a power pole with the RA axis off 90 degrees from vertical, lining up the plus with the top of the pole, then rotating the RA axis 180 degrees to see how far off it is, then adjusting the collimating screws on the polar scope to where the distance from the target to the pole is only 1/2 way off, then putting the plus back on the top and rotating the RA axis 180 degrees in the opposite direction to see if it's still centered.  Repeat until the plus stays on the target.  Don't worry if the whole field of view seems to still move even when the plus stays on the target.  It's only important to get the plus to stay on target.

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#3 SkipW



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Posted 05 March 2024 - 04:56 AM

When making adjustments to move the + to the center of rotation, don't loosen the grub screws too much or the reticule will fall out of position. If this happens, remove the scope from the axis, take out the eyepiece, remove the reticule (you'll probably have to clean grease off of it), back the screws out, drop it back in place (note the shape of the asterisms to get the right side forward), snug the screws, replace the EP, and start over.


The problem with centering using a distant object near the horizon is having to lower the polar axis to almost horizontal. It can be done but is a bit of a nuisance. OTOH, if the polar scope is horizontal, the reticule may be less likely to fall out, so there's that!


If you use Polaris, the polar axis will already be near the elevation angle you want; this is most easily done when the sky is dark enough to see Polaris but still light enough to easily see the reticule markings. 

#4 Thrifty1


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Posted 05 March 2024 - 08:32 AM

I picked up a used AVX last month and had to align the polar scope.

I did it during the daytime on a distant object. Much easier than at night.

Drop the altitude of the mount so you can target a daytime object. And then keep adjusting the set screws until the object stays centered as you rotate the mount.

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