polar alignment question

[Jezza94]

hi all,

i've just gone ahead and attempted to align my EQ2 mount, but i was wondering, what is the point of it? I know it's so you can track along the R.A but what does angle of the scope have too do with it?

if your going to observe an object that is lower towards the horizon, doesn't that defeat the purpose of polar alignment because you've changed the angle of the scope?

I hope this makes sense

I'm also having trouble polar aligning lol :(

[multiweb]

You need to have the RA axis parallel to the earth axis to track the sky or your whole starfield will shift. This is independant from where you're pointing your scope in the sky.

[2stroke]

If you don't have tracking motor, nor make use of the hand motion knobs and setting circles then it doesn't mater at all lol. But if your not making use of your eq2 features then it kinda feats the purpose of using one haha. Me and Forge might do a youtube video this week as so many people do and once you visually see how it done you will go its that simple? There are many on there probably the easit way not including drift alignment is to use a plumb bob to set alt angle and a compass and add or subtract your true south from magnetic south to get it point at true south. People say you can use solar noon but i think its a dumb arse idea if your changing location and don't want paint all over your cement ect. You also have to wait for solar noon and have a stick at 90 degress and then theres only a small window to mark in.

[Jezza94]

thanks for the time to reply guys.



A video would be great mate. I do have a tracking motor rigged up too it but I need to align before it serves any purpose ha ha.




Jeremy

[2stroke]

Heres a tut here http://www.iceinspace.com.au/63-498-0-0-1-0.html , i will do my best to get a video done this week. After this you can then use drift alignment to get the mount tracking perfect.

[gary]

Hi Jezza,

From your question, I can see that you are confused.

Your EQ2 has sprung handles with knobs on the end that, when rotated,
rotate the optical tube around its RA and Dec axes.
Those two axes of rotation are the ones you will use to find objects with.

However, your mount has two other axes which, once you have polar aligned
the mount, you will not adjust again on the night. The mount can be rotated
around in its azimuth axis and it can be tilted up and down in its altitude (also
known as its elevation) axis.

I have drawn a sketch for you which I hope will help. I drew a red arrow through
the mount's polar axis. When your mount is polar aligned, the arrow will be
pointing to the south celestial pole.

You can now see that the spring handles have nothing to do with the mount's
polar alignment. If you want to view an object near the horizon, you will rotate the
handles to move the optical tube to point to the target but that the red arrow I
have drawn in my sketch will still be pointing to the south celestial pole.

So, you may ask, where is the south celestial pole? If one were to use a camera and
take a continual exposure of the stars in the southern sky, you will see on the
image the stars creating trails that form concentric circles. The center of rotation
would happen to be the south celestial pole. If you were standing at the south
pole, it would be precisely overhead. As you move further north, it gets lower
on the horizon. Once you reached the equator, it would be exactly on the horizon.
Finding the south celestial pole in this way is not a practical approach, but
hopefully it gives you an intuition for where that point in the sky is.
On a chart, it is the point that corresponds to declination -90.

The links to the polar alignment guides other responders have posted will
provide a more practical approach.

As you can then appreciate, once the polar axis of your mount is aligned with
the south celestial pole, for practical purposes you can then follow an object
by just rotating the mount using the spring handle that controls the RA axis.

Anyway, I hope this response helps you as I sensed you were confused by the
various axes of your mount.

Best Regards

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place, Mount Kuring-Gai
NSW. 2080. Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au