5 replies to this topic

[BoldlyGoing]

Ran into a weird problem while imaging last night. Prior to a meridian flip, all of my 2-minute unguided subs show streaked stars. But after the meridian flip, it's fine, and the tracking is spot-on.

 

I'm wondering what the most likely cause of this might be.

 

- Bad balancing?

- Bad T-Point model? (I'm using TheSkyX with a MyT mount on a pier, and did a 36-point recalibrate for permanent mount prior to the run)

- Gears need lube?

- Something else?

 

Just looking for advice on where to start troubleshooting. Thanks!

 

[SoCalPaul]

Apologies up front if you already know this. My terminology is likely inaccurate, but the concept is sound afaik...

 

As I understand it, geared systems prefer to push against gravity, and not with it, so the system rides on the load-bearing teeth. For an equ mount, this means biasing your balance slightly to the east, so the system is constantly working to push it to the west.

 

Otherwise, there can be slippage and jumpiness when the system rides on the non-load-bearing teeth.

 

I don't know how imagers handle this for imaging sessions that involve meridian flips?

 

For visual, it's easy enough to adjust the cwt's.

 

Clear skies,

Paul

Edited by SoCalPaul, 16 May 2025 - 10:44 AM.

[Lvansoo]

How streaked were the stars in the images before the meridian flip? 

 

If the stars are streaked to the point where they look as if the mount wasn't tracking at all, then the mount may have hit the 'slew limit' before the meridian flip.

[BoldlyGoing]

The stars are just elongated, but not streaking to the point that it would suggest no tracking at all - and it affected the entire session while on the East side.

 

Just went out there and checked - it was balanced *very* slightly East-heavy already.

 

Maybe I should run a fresh full calibration for T-Point, just to rule out the ProTrack software doing something weird.

[kathyastro]

Are you sure that the elongation was in the RA (east-west) direction?  That would be RA backlash.  If it was in the Dec (north-south) direction, it could be declination backlash.

[BoldlyGoing]

I should have mentioned that... yes, the stars are elongated along the East/West axis.