Wandering Saturn

[gonzostar]

Hi I have a issue with a wandering Saturn.

Earlier in the evening I used my 102APO refractor on a Celestron  AVX mount no issue's what so ever and guided very well on NGC7000

 

Decided then to switch telescopes to the C8 to capture Saturn, again using the AVX  mount. The C8 Doesn't have a guide scope. Re-did PA though 

Saturn decided to wander from left to right, centered itself and drifted L-R again, repeated every 5seconds or so

 

What could be solution to keeping Saturn still?

1 Could it be that the set up is not balanced properly? 

2 Do i need a guide scope on the C8

3 Any other issues you can think off

 

Any suggestions would be grateful

Thankyou

Dean

 

 

[michael8554]

If by left to right you mean the drift is in RA only:

Then perhaps there's a high frequency component to the mount's Periodic Error.

So depends how large the L-R-L moves are in arcsecs.

They'd have to be only a few arcsec for typical guiding performance to minimise.

Michael

[CraigT82]

If the L to R directions of drift correspond to RA directions it could be a balance issue on the RA axis? 

[gonzostar]

9 hours ago, michael8554 said:

If by left to right you mean the drift is in RA only:

Then perhaps there's a high frequency component to the mount's Periodic Error.

So depends how large the L-R-L moves are in arcsecs.

They'd have to be only a few arcsec for typical guiding performance to minimise.

Michael

Thanks Michael, will look into Periodic error with AVX mount. The C8 doesnt have a guide scope on it. What confuses me is that Saturn  does wonder then come back into place every few seconds

However with the  ES102 Refractor on AVX mount no issues as its used with a guide scope.  

[gonzostar]

25 minutes ago, CraigT82 said:

If the L to R directions of drift correspond to RA directions it could be a balance issue on the RA axis? 

Thanks Craig you could be onto something there also. Everything does seam to be balanced perfectly before commencing. When Saturn is in the SE should the counterweight be slightly towards the scope or floor? 

 

Cheers

Dean

[CraigT82]

With Saturn in the SE you’d have the scope on the west side of the mount, CW on the east and the CW would be rising as it tracks. Once Saturn hits south the meridian flip would then put the scope in the east and CW in the west and the CW would be falling as it tracks. (I think that’s right, trying to visualise it in my head!)
 

Normally the weight wouldn’t change position on the bar at all, the balance point should be the same all around the whole rotation of the RA axis, but I know some people like to go slightly heavy on one side to help guide better by keeping the spur gear teeth engaged with the ring gear instead of floating between teeth. 

[gonzostar]

Cheers, will give this ago next time i want to catch saturn.

 

Dean

[bosun21]

This is puzzling. When imaging Saturn I basically have the planet static on the screen with a small ROI. This has been with an EQ5, HEQ5 and my AZ-EQ6. I've used a 120 apo, 180 Maksutov and even my 10" go to dobsonian. A small drift can be down to PA or not levelled properly with the dobsonian, but I've never heard of what you describe. I hope you find the culprit.

PS: AVX's can be quirky. I would put it through a factory reset.

Edited August 6 by bosun21

[gonzostar]

Yes Factory reset could be a option. Hadn't thought of that. 

Cheers

Dean