Declination drift method...

[timthelder]

Can anyone clarify/simplify this method of polar aligning?

The reason I ask is this,(I'll try and make this sound like it makes sense.) I am confused as to the direction I need to be adjusting my mount due to instructions using the terms North and South.

Example 1:
My mount is set up with the polar axis facing the north celestial pole.I find a star on the eastern horizon,and center it in my illuminated reticle eyepiece.(eyepeice is vertically oriented for comfortable viewing.)

The manual says:
If the star drifts south, the polar axis is too low.(this is reversed for southern hemisphere.)

Question:Does drifting South mean "in the eyepice", or in the sky?

Example 2:What's happening...

Facing East I center a star in my illuminated reticle eyepiece, the star then begins to drift farther East(or down in the eyepiece.)Not to the right in the eyepiece, which would be "drifting South".

Declination drift method makes no mention of what to do if a star drifts east or west...:duh:

The adjustments to my mount do not seem to be making much of a difference in getting an alignment that is good enough to do Long Exposure photography.

[Radar]

Hi Tim,

Welcome to Polar Alignment.

This is not as hard as it seems, though well written instructions for this process are rarely written.

When polar aligning you don't need to worry about the East West movement of the star. That movement will be taken care of when you guide a photo. It is the up and down movement that you need to worry about.

I tried polar aligning for ages, I read many tutorials, none made sense to me. I decided to disregard everything that was written and go raw.

This is how I ended up learning. Read this a few times -

Once your polar axis is pointing to the North Celestial pole, find a star high up in the South. Put your reticule eyepiece in the telescope, find a star (doesn't have to be a bright one). Centre the star, then rotate the eyepiece so that the star can move along the east west line of your reticule. Once you have done this, put the star back in the middle and watch for drift.

Now forget those nasty instructions that came with the scope, because you are going to learn your scopes parameters by yourself here. It's much easier.

Watch for drift. If the star drifts up or down, it's because your scope needs to be moved to the left or right (east or west).

But how do you figure out which way to adjust the scope?

Just experiment to find out what works. If the star moves up, try and adjust the scope to the West slightly, then place the star back on the line of the reticule. You'll notice that the star will either drift off the line faster or slower this time. If it drifts faster, then you adjusted the wrong way, if it drifts slower, you adjusted the right way. Make more adjustments until the star does not drift at all.

You can use a timer to measure the length of time that the star takes to drift from the line. This will help you narrow down which way to adjust the scope.

Also using a Barlow lens will make the star drift off the line quicker, which means quicker alignment.

Polar alignment is an annoying skill to learn, but once you get the hang of it, Astronomy becomes much more pleasurable. Expect to practice this technique a bit. It may take a few sessions.

Good luck mate. :thumbsupmate:

Ray

[hpcoolahan]

Heres a link for a cool program i use, click on the drift align instructions too!

http://www.andysshotglass.com/StarTarg.html

Cheers Pat

[timthelder]

Thanks for the help mates,

I guess I'll eventually get it,just a little anxious to get some decent pic's especially with a comet in view...

[Radar]

I guess I'll eventually get it,just a little anxious to get some decent pic's especially with a comet in view...

It's a horrible feeling knowing that a celestial event is happening, and for some reason you can't photograph it. I've been here many times. Just experiment with your mount and make adjustments as much as you can. What which way the star drifsts, write down everything that happens!

Ray

[timthelder]

I GOT IT!:Chessy_Smile:

It took a couple of hours, but once I figured out that South means South, and North means North, instead of worrying about the star moving right or left, or up or down, it was basically a cinch.

I'm sure I'll speed up the process when I figure out how much adjustment to make based on how fast the star drifts off center...:thumbsupmate:

Thanks fellers...

[hpcoolahan]

congrats and good luck with the comet photos.

Clear Skies

Pat

[AstroBob]

polar alignment, uggh :ahh!:

[Brianon]

Another great link .Thanks for the tip Pat.:thumbsupmate:

CHEERS Brian.

[wakaleo]

Andy's Shot Glass is a cracker of a site. Heaps of great info presented in a straightforward and easy-to-understand manner. Thanks for the link Pat.

Jim