Difference in Angle of Tube and Mounting Plate

[mikeyjames (Mick)]

Hi all,
I'm really loving the telescope after two weeks off work to get used to it. Back at work today. One thing I am beginning to realise is how accurate things need to be to get the goto working and finding targets.

For example yesterday I set up using my compass (with magnetic dec set) and a wooden T-shaped contraption that fits between the legs of the tripod, and my inclinometer. I told it to find the sun and it did. I then asked it to point at the moon and it missed. I manually adjusted things until it found both targets and then parked the scope. The difference between what I started with and where it ended up - One notch on the DEC scale and such a small change on the RA scale it would be hard to measure.

This brings me to my issue - I have noticed that when I measure the angle of the mounting bracket it is 33.95 degrees which is what I want. Then when I attach the scope, the angle of the scope is actually 34.1 degrees.

Given the level of accuracy needed could this be causing me some issues?

Also how do I fix it? Would I need to find a way to adjust the angle of the scope by maybe putting something thin between scope and mounting plate or would I simply adjust the bolts on the mount to get the scope at 33.95 degrees?

I hope that all made sense.

Thanks
Mick

[doppler (Rick)]

That may be what is known as cone error. Here's a video that will explain what it means and how to adjust your scope.
https://www.youtube.com/watch?v=WatdQlPp22Y

or a quick read http://www.cloudynights.com/page/art...rocedure-r2447

[mikeyjames (Mick)]

Originally Posted by doppler

That may be what is known as cone error. Here's a video that will explain what it means and how to adjust your scope.
https://www.youtube.com/watch?v=WatdQlPp22Y

or a quick read http://www.cloudynights.com/page/art...rocedure-r2447

Thanks Rick, just watched the video and it seems to be exactly what I need.

[doppler (Rick)]

I think that every little tweak you can do makes the whole goto more accurate on a regular basis. The other videos in the astronomyshed series are also quite good.

Another good youtube series for astrophotography scope setup is by Forrest Tanaka https://www.youtube.com/watch?v=sW8NyT3r2LU

[mikeyjames (Mick)]

Originally Posted by doppler

I think that every little tweak you can do makes the whole goto more accurate on a regular basis. The other videos in the astronomyshed series are also quite good.

Another good youtube series for astrophotography scope setup is by Forrest Tanaka https://www.youtube.com/watch?v=sW8NyT3r2LU

Thanks Rick.