Impossible question is there an easy answer

[UK1 (Rob)]

Impossible question is there an easy answer

I have an EQ6 pro mount with all the goto bits ...I know you have to align it to true south which I can and set all the east and south bits can do with no problem. But what the problem is, is finding the South Celestial pole I know its very faint I have seen all the ways to find it using the Southern Cross and the Pointers but the area of sky its over there is some light pollution more than normal, cant even see Octans through finder scope let alone the polar scope. The question is there any way of getting a good alignment with out using South Celestial pole so I can use my goto mount and start tracking and start my photography, as I’ve spent a lot of money on getting all the
equipment together…...thanks

[Quark (Trevor)]

Hi Rob,

Just use the star drift method, it really is the most accurate way to polar align an equatorial mount and after a few times becomes relatively easy to do. You don't need to be able to see the stars in the region of the SCP to polar align.

Cheers
Trevor

[RB (Andrew)]

I agree with Trevor, I've only ever drift aligned, I've never used the polar scope on my mounts.

[[1ponders] (Paul)]

What's a polar scope???? Star drift.

[sheeny (Al)]

As the other guys have said... drift align.

BUT...

To get you started, before you get to drift aligning, have a look at this method:

http://www.iceinspace.com.au/forum/s...ight=alignment



or use a compass to compensate for your local magnetic declination. I still think my "rough" method will get you closer than a compass, unless you happen to jag it.

Al.

[Wavytone]

This assumes you have a mount with an accurate dec circle, 1-degree divisions are perfect and it is straightforward to align within a degree of the pole in a matter of 10 minutes, faster than the drift method.

Step 1: choose a known bright star near the east or west horizon to set the azimuth of the scope:

- use an atlas to find the dec of the star,
- set the dec axis to the dec of the star as per the atlas, and lock the axis,
- slew the RA axis (east/west) and adjust the AZIMUTH of the mount until you can centre the star in the finderscope, then in the main scope.

Step 2: choose a known bright star overhead to set the altitude of the mount:
- use an atlas to find the dec of the star,
- set the dec axis to the dec of the star as per the atlas, and lock the axis,
- slew the RA axis (east/west) and adjust the ALTITUDE of the polar axis until you can centre the star in the finderscope, then in the main scope.

Notes:
~~~~~
You must set the azimuth first; otherwise its likely you will have to repeat steps 1 and 2 a second time.


This method assumes:
- you have a finderscope or telrad properly aligned with a small refractor or guidescope with a field of view of say 2 degrees - you don't want lots of magnification.

- the dec circle is reading true with respect to where the scope is pointing. If the circle has an offset you must fix this first. If you don't know how to do this (easy in daylight), ask...

The accuracy is about half the divisions on your dec circle (ie half a degree on many scopes).

The Vixen StarBook uses a very similar approach in software to work out how to convert between equatorial coordinates and the circles on any telescope that is not actually aligned on the pole.

[OneOfOne (Trevor)]

A compass, with the appropriate deviation correction will get you pointing in the right direction, but even if you were in the northern hemisphere, aligning on Polaris would not be accurate enough for astrophotography...it is just a bit more convenient than Octans down under. As everyone has said, drift align is about the only answer, short of a permanent mount, which would need to be polar aligned in the first place anyway...using drift.

[astro_nutt]

Hi Rob..
Here's another one to try...after ensuring your mount is level..us a compass find true South which is about 11.5 degrees to the East...from your Latitude raise your scope to that amount (say 37 degrees) above horizontal..then drift align from there..
Cheers!

[Geoff45 (Geoff)]

Originally Posted by astro_nutt

Hi Rob..
Here's another one to try...after ensuring your mount is level..us a compass find true South which is about 11.5 degrees to the East...from your Latitude raise your scope to that amount (say 37 degrees) above horizontal..then drift align from there..
Cheers!

Just don't put the compass near the metal of your mount.
Geoff

[Geoff45 (Geoff)]

Originally Posted by Wavytone

- the dec circle is reading true with respect to where the scope is pointing. If the circle has an offset you must fix this first. If you don't know how to do this (easy in daylight), ask...

OK, I'll bite. How do you do it?
Geoff

[Paul Hatchman]

Originally Posted by RB

I agree with Trevor, I've only ever drift aligned, I've never used the polar scope on my mounts.

And if you want to try a technological solution to the problem of drift aligning, you could try out something like the WCS software.
http://wcs.ruthner.at/index-en.php

I've used it with a meade dsi and an eq5 and it worked quite well. For me, it was quicker than manually drift aligning.

[RB (Andrew)]

Originally Posted by Paul Hatchman

And if you want to try a technological solution to the problem of drift aligning, you could try out something like the WCS software.
http://wcs.ruthner.at/index-en.php

I've used it with a meade dsi and an eq5 and it worked quite well. For me, it was quicker than manually drift aligning.

Yep, thanks Paul, I've been meaning to give this one a go for a long time.
Looks like a great utility.

Another one I want to try is K3CCD for drift alignment.

Thanks for the reminder.

[Wavytone]

Originally Posted by ghsmith45

OK, I'll bite. How do you do it?
Geoff

Normally done in daylight - assemble scope on mount so you can focus on an small, distant target (anything).

With the scope on one side of the mount, read the dec circle - call this D1.
Flip the scope over to the other side of the polar axis (equatorials) or rotate the fork 180 degrees (fork mounted SCT), centre on the same target and read the dec axis again - call this D2.

If D1 and D2 aren't equal the circle isn't reading true and the correct value = (D1+D2)/2. While the scope is still pointing at the target, adjust the circle to read the correct value.

There may also be another error in cheap mounts - if the circle is not concentric with the actual axis of rotation the circle may read true in some positions but not in others. There may be not much you can do about this other than be aware of it. Try a few other targets say 60 degrees apart and if they all agree to 0.5 degree or better the circle is fine. You can probably do this with digital circles too, though when getting down to minutes of arc expect to detect errors from non-concentricity.