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Polar aligning


scottphillips

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Hi guys, just took my new skywatcher 130m eq-2 out for a test run and am really impressed with the views I got of andromeda and the Pleiades !!

I have read up about polar alignment and basic use of an eq mount and just want to double check

Polar alignment:

So I ligned the eq mount up with the North Star and it appeared in the middle of my scope when I looked through

Use:

I had a little trouble moving the scope to find objects so loosened the knobs and slewed to them manually and then tightened the objects again. Is there any better way I could do this or is this the only way ?

And lastly when I eventually attatch my motor drive how do I ensure that it accurately tracks my object

Thanks

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The poalr alignment may be good or may be way off.

Cannot put it any other way.

If the scope and the mount rotational axis are parallel then it will be good, however it is the mount that is polar aligned not the scope. So putting polaris in the centre of the scope may not mean much. Think about it - the scope points where you want it to independant of the mount otherwise all you will ever see is polaris (and maybe not even that).

Since the EQ2 does not accomodate a polar scope I am not sure how accurate any poalr alignment would be, it really will have a degree of best guess in it all. You will be relying on how well aligned the scope and mount axis are set up in respect to each other.

As to how well it tracks, set it up, stick something like Vega or Deneb in the centre and just leave it and see how much it drifts in say 120 seconds.

The mount is manual so all you can do is release the clutches and slew it manually and then use the flexible twiddly things to place objects in the centre of view.

If this is for visual observing then you will just have to set everything as best you can. If objects stay in vies for say 120 seconds then you have the adjusters to recenter them.

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One way to get a very rough polar alignment is to set up your mount so that the counterweight shaft is aligned north-south (use a compass if needed) then elevate the mount to your latitude on the scale (52 degrees in my case). I do this with my Tal and it works reasonably well for short-time visual observations. Be careful not to let the compass get too near the steel parts of the scope though! The paving slabs on our patio happen to run north-south so I use the edge as a guide.

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I bought a used polarscope for the eq3-2. They are cheap enough new. Just align Polaris on the circle in the direction of Kochab and job done. The RA motor is incredibly good and I use batteries which last for ages. Really lovely grab and go mount,

Nick.

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One way to get a very rough polar alignment is to set up your mount so that the counterweight shaft is aligned north-south (use a compass if needed) then elevate the mount to your latitude on the scale (52 degrees in my case). I do this with my Tal and it works reasonably well for short-time visual observations. Be careful not to let the compass get too near the steel parts of the scope though! The paving slabs on our patio happen to run north-south so I use the edge as a guide.

Sorry - I've confused the issue here. As Ronin says it's the mount that needs to point north. The counterweight shaft can only be used as a guide if it's lined up with the centre of the mount, viewed from the front. When the latitude is set it can then be used as a guide by viewing it from above. The best way by far though is to get a polarscope ,as Nick recommends. I have one on my eq5 and once set I can track for much longer without correction than with the Tal, unless I spend time doing star drift alignment.

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Once on a target you can use the RA and DEC to navigate to nearby objects without loosening the screw locks. For this you need a star chart to work from. For example, I always go to the Dumbell Nebula M27 by putting the red dot finder on γ Sagitta, then just use the DEC to pan North a bit until M27 comes into view. That cursed DEC mechanism on the EQ2 can reach the end of its rope, though! You then have to twist it in the opposite direction to allow enough slack, and reposition on your object by loosening the lock. This doesn't happen often but is always when you are 95% of the way to your target.......but not quite :-O

Of course, for just observing, the polar alignment doesn't need to be spot on. Even lining up on Polaris will be a little off as the North celestial pole is a little to the side of the star.........but darned close! If you tend to set up in the same location, then polar alignment is a snap: straighten up the RA & DEC, put the legs in the usual position, red dot finder on Polaris, and hey presto!

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