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View Full Version here: : DEC Oscillations - how do i fix?


glend
25-07-2016, 11:24 AM
My NEQ6Pro mount has an annoying DEC oscillation under guiding that results in my DEC guide graph over correcting up and down - chasing. The mount has a belt drive system and it seems well adjusted. No issues in RA at all. I run Metaguide. I have raised the correction period to 2. I image mainly to the east and the load is balanced to be slightly east heavy on the RA axis. The DEC balance is neutral. Should i be heavy on one side in DEC balance? I would like to clean DEC up. Btw the mount is on a pier in my observatory and DEC elevation is perfect. Suggestions?

Bart
25-07-2016, 11:36 AM
Yes, try a little loading on the DEC, it may be bouncing if it is too well balanced.

glend
25-07-2016, 11:41 AM
I was thinking it might be the DEC wormshaft end play but i can't detect any slop when i try to move it.
In terms of loading one side, which one? The camera side (its in front with my Mak-Newt) or the rear, or does it make a difference?

gregbradley
25-07-2016, 12:42 PM
If you have a bit of backlash in your system and you are perfectly balanced a decent mount can still do that.

I have had that happen to me a few times. I simply unbalanced it slightly and it stopped straight away.

You then should check the tightness of your system if there are adjustment points to reduce the play.

Greg.

billdan
25-07-2016, 05:52 PM
I used to get those DEC oscillations with my EQ6 and simply solved it by guiding in DEC one direction only.
This only works with a good polar alignment e.g. If your polar alignment has a very slow drift North then set PHD to correct only if the star moves South because your polar alignment protects you if the star tries to drift North.

Cheers
Bill

P.S. You must reverse it after a meridian flip.