Arghh! Polar alignment and goto etc.

[duzzy]

Hi Dark Knight.

Thanks for the info re K3ccd. That is what I am going to do next clear night.

You say "drift explorer then does a clever calculation and calibrates the RA and Dec directions"

Is it pretty obvious where these calculations appear and what to do with them?

Cheers

J

[dark knight]

Hi J, itis as simple as pressing a button a few times, just follow these instructions and it should make sense. Read through a few times and I'm sure you will find it easy..

Using the K3CCDTools Drift Explorer for Drift Alignment - IceInSpace

[duzzy]

Thanks for the link. That's brilliant! I did find another howto in pdf format but that was for an alt/az mount which added another level of confusion for me.

Roll on that high pressure system we are being promised.

All the best,

J

[duzzy]

Hi,

Just had a go with drift explorer. Measured camera angle and started measuring.

I was tracking Mintaka as this is a star I can see and one that is near 0 degrees declination.

To start with the dec line would start at zero and then drop to the bottom of the graph. I've adjusted the altitude on the mount (which now reads nearly 60 degrees!!! I'm at 51!!!) until the dec line more or less bumps along in the centre of the graph. As it happens the RA line was not too bad.

What confuses me is if I now slew to a star in the NE the dec and RA lines start to drift again. Quite badly.

Huh?

I thought I was starting to understand this. Aligning the N/S

axis of the mount to point at the NCP is to get my scope to slew accurately to the star's declination (so the movement in dec is then over?). RA is also used to slew to the star and then counter the Earth's rotation (continous movement).

If the drift explorer declination graph seems ok at 0 degrees. Why is it off elsewhere?

J

[themos]

here's the deal: Mintaka is almost South, right? What do stars do there, the ones near the equator? They go left to right with very little up and down movement. If you're tracking a star in the South, it's the mount's azimuth that you need to adjust until the declination drift flatlines. Watch my video to understand this:

[duzzy]

Cheers. I'll check the video tomorrow.

When I started, about 8pm Mintaka was in the east at midnight it will be south (here is where my head starts to spin. It won't really be in the south will it? At 0 degrees declination i thought it could only really move East to West?? and because of my latitutude it only appears to be in the south. At the equator it would just roll straight over my head?). I can only look east so only played for about 2 hours. Which took mintaka from E to SE.

I thought that I adjusted declination (altitude?) when the scope was tracking a star either east or west and RA (azimuth) when I was tracking a star either north or south (which I cannot do from my viewpoint).

Thinking I may pull it all apart and start again. Check pillar is level etc.

Cheers

J

[duzzy]

Actually I think I will give WCS a try and see what I get then.

J

[Vic&Al]

I am new to this forum, and quite new to astronomy, so go easy on me if this is unfeasable but its just an idea so here goes.

If you know your exact latitude, with a compass, laser pointer, spirit level, and a protractor (and some fine adjusting) you could project a NCP onto a wall or other obstruction, from which could you align your mount?

I know this is not exact precission but could it work?

[duzzy]

Well WCS was good fun! I liked the way it told me in what direction to move, with helpful lines on the screen.

What did become apparent was that I was WAY off. Move 9x, repeat move 9x, move 22x. In the end the penny dropped that I was so way off that I should start again.

So today I have checked my mount is level. Then I wound the altitude adjusters to 0 degrees and put a spirit level on the mount. My altitude gradient is only about 1 degree out so I have used that to get me to 51 ish and used the compass to re-align North. Then I'll give WCS and K3CCD drift explorer another go.

The good thing is I think I have really learnt lots of good stuff from having these hassles.

Thanks to everybody for their help and patience!

J