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Offset pier

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#1 benbendube

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Posted 05 May 2021 - 02:47 PM

I Read somewhere that the pier should have an offset to the center of the observatory.

Can someone explain this to me?

  A.D.Ben


Edited by benbendube, 05 May 2021 - 02:48 PM.


#2 PETER DREW

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Posted 05 May 2021 - 03:23 PM

It depends on the type of mount, an Alt-Az mount would be more likely to be set centrally.  An Equatorial mount, specially a fork mount , is usually offset towards the South as the inclination of the polar axis displaces the telescope towards the North.  This situation varies with the latitude of the observatory.


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#3 Topographic

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Posted 05 May 2021 - 03:42 PM

My pier is offset but by accident, the concrete plinth was put in slighly off. It isn't a problem, you just put the measurements in to your rotator set up (if you are automating). I also have mine slightly to the south because I wanted more room to the entrance which I wanted to be opposite the direction of the prevailing wind from the south.


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#4 MJB87

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Posted 05 May 2021 - 03:46 PM

In my ROR the pier is offset for practical reasons. First, I wanted to be able to have the telescope view clear the open roof to the north easily. Since the south wall folds down, there isn't as much of a challenge in that direction.  Second, I wanted to create some working space on the north side for a table, chair, computer, etc.  This has worked out pretty well for me.

 

In my dome we tried to get the pier exactly in the center of rotation and missed by only 1-2 cm.



#5 benbendube

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Posted 05 May 2021 - 05:28 PM

How much of an offset with eq6-r pro at 45° north and in which direction? 



#6 MJB87

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Posted 05 May 2021 - 08:28 PM

My offset was 1 foot south in an 11.5x11.5 ROR



#7 SkipW

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Posted 21 May 2021 - 10:25 AM

How much of an offset with eq6-r pro at 45° north and in which direction? 

 

At least as a starting point, you would probably want to shoot for the intersection of the polar and dec axes to be at the center of the dome. Set the PA to your latitude, drop a plumb line from directly below the intersection of the axes, and measure how far it is from where the center of the pier will be (i.e. the center of the tripod locking shaft).

 

How much room will you nominally have between the dome and the nearest point on the telescope? Honestly, it may not be worth worrying about unless this tolerance is tight.



#8 benbendube

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Posted 21 May 2021 - 06:54 PM

I' waiting for my Pulsar 2.2m observatory with a Celestron 925 EDGE so I shouldn't worry about space, .even with a dew shield?

   A.D. Ben.




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