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(Sorry) Another Q on the CGEM Polar Align sequence

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#26 freestar8n

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Posted 12 February 2010 - 09:41 AM

That's why I asked the question earlier. If this is the case, then the mount doesn't compensate for the manual movement in Alt/Az. Or am I missing something?



Hi-

There is a related discussion ongoing in a similar thread - but basically AllStar knows how far off the polar alignment is (just use Align/Polar Alignment/Display to see the error in Alt Az) but the hc has no ability to physically move the mount in alt/az - which is what is needed to become physically polar aligned.

So - it intentionally aims 'off' from the alignment star and asks a human to move the mount until the star is centered - at which point it assumes it is perfectly aligned.

As long as the mount has been moved cleanly in alt/az motions of the correct distance, AllStar knows how the mount is now aligned against the sky and can do GoTo's directly.

If there were big motors to move the equatorial head in alt/az, the hc could do it all by itself - but it uses a human instead.

After the alignment, the displayed polar alignment error is 0,0 - since it assumes it is now perfectly polar aligned and it has no other information to go by unless someone replaces alignment stars - at which point those errors will show as non-zero, but hopefully small values.

Frank

#27 David Pavlich

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Posted 12 February 2010 - 10:47 AM

That's why I asked the question earlier. If this is the case, then the mount doesn't compensate for the manual movement in Alt/Az. Or am I missing something?



Hi-

There is a related discussion ongoing in a similar thread - but basically AllStar knows how far off the polar alignment is (just use Align/Polar Alignment/Display to see the error in Alt Az) but the hc has no ability to physically move the mount in alt/az - which is what is needed to become physically polar aligned.

So - it intentionally aims 'off' from the alignment star and asks a human to move the mount until the star is centered - at which point it assumes it is perfectly aligned.

As long as the mount has been moved cleanly in alt/az motions of the correct distance, AllStar knows how the mount is now aligned against the sky and can do GoTo's directly.

If there were big motors to move the equatorial head in alt/az, the hc could do it all by itself - but it uses a human instead.

After the alignment, the displayed polar alignment error is 0,0 - since it assumes it is now perfectly polar aligned and it has no other information to go by unless someone replaces alignment stars - at which point those errors will show as non-zero, but hopefully small values.

Frank


Got it. Thanks, Frank!

David

#28 SanDiegoPaul

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Posted 12 February 2010 - 11:50 AM

Frank thanks for answering my & David's questions so well. Hopefully we'll get under some stars this weekend to re test what you're saying.






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