Drift alignment with a webcam and k3CCD tools

[Kaptain Klevtsov]

This polar alignment method works if you have K3CCD tools, and works even better if you have the paid-up version.

Fit the webcam into the 'scope and focus on a star and rotate the webcam so that the movement on the screen is as near exactly laft right when slewing in RA. (RA is the axis that rotates around the polar scope, the lower one if you like). Using the cross hair reticle helps a lot here.

Find a star that's east or west low down and centre it in the cross hairs. Wait for it to go up or down. Sideways movement is not an issue here, just up or down on the screen. If it moves you must alter the altitude of the 'scope and recentre the star until the up and down movement of the star goes away. As the webcam orientation, 'scope type and mount adjustments all vary, you'll have to work out which way is which for your setup, but once you work out which way to turn the screws it isn't a big job.

Once the east or west star is not moving up or down, find a star due south ish. The height of the star should be such that the 'scope is pointing at 90 degrees to where the polar 'scope is and it's easy to judge by looking at the mount. Currently the right hand belt star is ideally placed for this. Again centre a star and wait for it to go up or down. Adjustment this time is by the mount azimuth screws (side to side adjustment). Repetitive adjustment, recentreing and waiting will get it bang on. The initial drifting is quite fast when the mount is a fair way out of adjustment so the waiting is only a matter of seconds. To get it just right you can set it up so that no movement is apparent at all.

If the azimuth was a long way out it's a good idea to go back to the east or west star and check that the azimuth adjustment hasn't messed it up. It should still be very close so only a tweak should be required if anything.

The good bit about the paid for version is that you can open the drift explorer and click on a star. K3CCD will report the direction of drift and the amount of drift so that it'll tell you where the star is going before it's even noticeable. Don't jump in too soon as periodic error just might catch you out if you jump the gun and tweak too soon.

Once you have the direction of adjustment sorted it's not very difficult, and much more accurate and comfortable than the polar 'scope.

HTH

Captain Chaos

[geppetto]

HTH

Sure does CC

Just been looking into it to have a go at drift aligning

my new mount.

That sounds a much more comfortable way of doing the job

Thanks matey

[magician]

That sounds good CC,will play with it as soon as I can see the sky,I do have the paid-up version of K3.

Cheers Frank

[MartinB]

CC, what is the advantage over just using an illuminated reticle?

[geppetto]

CC, what is the advantage over just using an illuminated reticle

I thought that but then I checked how much an illuminated reticle eyepiece is :shock:

Plus with the computer screen, you have a bigger resolution for tweaking.

[Kaptain Klevtsov]

CC, what is the advantage over just using an illuminated reticle?

You have to be able to look down the illuminated reticle and remember which way is up. With my 12" Newt. looking down the EP is sometimes non-trivial . Also the zoom option isn't available with an EP, nor is a readout of the drift rate.

With my EQ6 being so low down, manual looking through the Mak. is almost as bad as looking up the polar 'scope. The Mak. is the weapon of choice for getting the alignment sorted as the focal length is high so any drift is magnified accordingly.

Captain Chaos

[CELESCOPE]

sounds good CC , but wont do anything till i have a perm fix , have a lot of things planned for the future ,

Rog

[MartinB]

Fair enough CC. I might give it a try although I'm pretty happy with my trusty reticle. Philip, the reticle EP is a godsend for me, not just for drift aligning but also for aligning the goto. If you don't use goto and want to drift check the direction of the dec movement and line a star up just at the edge of the FOV. see whether it drifts out of view or comes more into view. That works.

[geppetto]

Philip, the reticle EP is a godsend for me

Yes, not knocking them Martin, will get one at some point, would be handy for aligning

to get stuff on the Toucam's chip.

But, it's yet another lump of cash

[Chris Graham]

Its the only way i drift align, saves buying a illuminated eyepiece and works a treat.

Good write up m8 !