Jump to content


Photo

Atlas EQ6 kept drifting after slew

  • Please log in to reply
24 replies to this topic

#1 Puck Ja

Puck Ja

    Apollo

  • *****
  • Posts: 1064
  • Joined: 21 Nov 2012
  • Loc: OK, USA

Posted 09 September 2013 - 11:58 AM

When I had my XT8 on Atlas (about 2 year old), onces in a while I notice that the mount kept moving after slew command. I have ensure mount was well balanced. It is visible on my imaging CCD looping at about F/3. This happened with both hand controller or EQMOD. Usually I can issue another slight "slew" to the opposite direction to stop the drifting. There may be once that the drift was bad that I have to "reboot" the mount.

Recently, I put C11 on Atlas, it was working alright for two nights. Then last night I notice quite large drift after my last slew. The PHD display of my SSAG view shows the star moving gradually out of FOV. That was significant and I just stop my session.

I have googled quite a bit but have never get firm answer on the cause and fix of this issue.

Thanks a lot for the help!

#2 Puck Ja

Puck Ja

    Apollo

  • *****
  • Posts: 1064
  • Joined: 21 Nov 2012
  • Loc: OK, USA

Posted 09 September 2013 - 06:35 PM

No one has experienced it? I thought that I read a lot of reports...

#3 rigel123

rigel123

    Voyager 1

  • *****
  • Posts: 11166
  • Joined: 29 Jun 2009
  • Loc: SW Ohio

Posted 09 September 2013 - 10:24 PM

A lot would depend upon your initial alignment. If your PA is off by enough you might see this. Also, just to be safe check your tracking rate to make sure it is set on Sidereal Tracking.

#4 achronut

achronut

    Explorer 1

  • -----
  • Posts: 98
  • Joined: 23 Jan 2009

Posted 10 September 2013 - 12:45 AM

Using the hand control was when I experienced such drift. When I interrupted the slew by pressing the ESC button before the mount reached its target, the RA drifted by itself. Had to reboot the mount.

#5 John Carruthers

John Carruthers

    Skiprat

  • *****
  • Posts: 3551
  • Joined: 02 Feb 2007
  • Loc: Kent, UK

Posted 10 September 2013 - 02:28 AM

First check your power supply. They need 12V 2A minimum and are happier with more, I run mine at 13.4V. All sorts of madness happens if the power drops.

What are the backlash settings on the handset? try setting them to zero and see if it still does it.

I have also heard of earth loop problems causing 'extra' slew but you'd have to diagnose and eliminate that one bit of kit at a time.
One eq6 I tuned 'drifted' simply because of bad guider calibration.

#6 NigelM

NigelM

    Explorer 1

  • -----
  • Posts: 54
  • Joined: 22 May 2009

Posted 10 September 2013 - 06:51 AM

My HEQ5 started to do this after several years of use. I stripped it down, cleaned the worm and gear, readjusted and the problem has gone away.

NigelM

#7 Puck Ja

Puck Ja

    Apollo

  • *****
  • Posts: 1064
  • Joined: 21 Nov 2012
  • Loc: OK, USA

Posted 10 September 2013 - 09:43 AM

Thanks to all the replies. I would like to clarify my issue. It is not due to bad PA or GOTO alignment or autoguiding. The mount, when the issue occurred, will "over-shoot" after the slew command, like a heavy car cannot stop well behind the STOP sign. :) But once the mount stop, it will not drift and follows the autoguider well.

I suspect that this may be backlash (or any looseness in the mechanical chain), balance, and weight related. I just saw a view on Astroshed talking about balancing at different orientation. That reminds me that I may not did a good job on balancing.

Last night I switch back to Orion XT8 (lighter load to Atlas) and did not saw the large moving after slew to position.

#8 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 10 September 2013 - 02:38 PM

Backlash won't produce this result AFAIK. If you are currently driving on that axis, any backlash would _already be taken up, you see. Backlash would only appear when the direction of the slew was reversed. Main causes of this sort of behavior? Poor balance and computer/connection/power problems.

#9 MikeCMP

MikeCMP

    Vostok 1

  • *****
  • Posts: 185
  • Joined: 12 Jul 2011
  • Loc: Chardon OH

Posted 10 September 2013 - 04:45 PM

Other problem could be PAE data in the hand box adding corrections after a slew. It's aspic ally extra syncs you may have done to I prove pointing, if you have moved the mount and never cleared the sync data it could be adding an extra calibration to the end of the move.

Go into the utility menu, I think, and select PAE. I know there is a selection to clear it, and probably to view it. See if there is anything there and wipe it out.

Mike

#10 Puck Ja

Puck Ja

    Apollo

  • *****
  • Posts: 1064
  • Joined: 21 Nov 2012
  • Loc: OK, USA

Posted 10 September 2013 - 06:11 PM

Thanks again for the input. I understand it does not sounds like backlash issue. And I have tried both HC and EQMOD, it has occured in both cases.

My feeling is that it may be due to no-well-tightened Lock lever and poor (even though good at one orientation). I'll try to balance the mount at multiple orientation to see if this issue goes away.

Thanks!

#11 Bill W.

Bill W.

    Vanguard

  • *****
  • Posts: 2434
  • Joined: 09 Oct 2005
  • Loc: Western PA, USA

Posted 11 September 2013 - 12:32 AM

May be gear mesh. I only say that because it would take a second for the slop to be taken out. Does it track well afterwards and how is your guiding?

-Bill

#12 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 11 September 2013 - 09:02 AM

May be gear mesh. I only say that because it would take a second for the slop to be taken out. Does it track well afterwards and how is your guiding?

-Bill


How will gear slop make the scope continue slewing in the same direction after it is supposed to have stopped?

#13 Bill W.

Bill W.

    Vanguard

  • *****
  • Posts: 2434
  • Joined: 09 Oct 2005
  • Loc: Western PA, USA

Posted 11 September 2013 - 09:43 AM

Title of the post is:

>Atlas EQ6 kept drifting after slew

After. It didn't say continue.

First paragraph.

>When I had my XT8 on Atlas (about 2 year old), onces in a while I notice that the mount kept moving after slew command. >I have ensure mount was well balanced. It is visible on my imaging CCD looping at about F/3. This happened with both >hand controller or EQMOD. Usually I can issue another slight "slew" to the opposite direction to stop the drifting. >There may be once that the drift was bad that I have to "reboot" the mount.

"kept moving after slew command." I take he meant after the slew had been completed. Also, if issuing a 'slight slew' in the opposite direction stops the 'drifting' then, to me, that points to gear mesh/slop or a balance issue.

-Bill

#14 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 11 September 2013 - 12:56 PM

"Kept" and "continue" are purty much the same thing round these here parts... ;)

#15 Bill W.

Bill W.

    Vanguard

  • *****
  • Posts: 2434
  • Joined: 09 Oct 2005
  • Loc: Western PA, USA

Posted 11 September 2013 - 01:29 PM

They aren't round here... :)

-Bill

#16 Bill W.

Bill W.

    Vanguard

  • *****
  • Posts: 2434
  • Joined: 09 Oct 2005
  • Loc: Western PA, USA

Posted 11 September 2013 - 01:49 PM

Don't forget kept drifting AFTERr slew. ;)

-Bill

#17 MikeML

MikeML

    Viking 1

  • *****
  • Posts: 509
  • Joined: 09 Oct 2004
  • Loc: NJ

Posted 11 September 2013 - 02:50 PM

Couldn't be mirror flop?

#18 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 11 September 2013 - 02:59 PM

They aren't round here... :)

-Bill


That's fine, but gear mesh causing his problem just doesn't make a lick of sense. Sorry. :crazy:

#19 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 11 September 2013 - 03:00 PM

They aren't round here... :)

-Bill


That's fine, but gear mesh causing his problem just doesn't make a lick of sense. Sorry. :crazy:


And "after the slew" means after he got to the object it kept moving.

#20 Puck Ja

Puck Ja

    Apollo

  • *****
  • Posts: 1064
  • Joined: 21 Nov 2012
  • Loc: OK, USA

Posted 30 September 2013 - 02:33 PM

Thanks guys for the input and "interesting" discussion on guessing what did I exactly mean. :)

The symptom was that the I assumed the scope finished the command (since it didn't beep as the hand controller did) and the stars in FOV still moves a continuously for a while.

After more carefully balance the mount at MULTIPLE orientation, and make sure that I ensure the level locks were tight. I have not seen such drifting anymore, even with the C11. :)

I guess that those two mentioned improvements are the keys to resolve such issue.

I hope this may help someone in the future!

#21 WillCarney

WillCarney

    Apollo

  • *****
  • Posts: 1465
  • Joined: 08 Oct 2009
  • Loc: Bloomington, ILL

Posted 01 October 2013 - 02:59 PM

I've had some alignment and drift issues with my Atlas recently. According to Orion Tech service they have bugs in the newest Atlas firmware. The new firmware is designed for the EQ-ALT mount and seems to cause problems when in the EQ mode. They were not sure when and if a fix is forthcoming. Check the thread on Atlas firmware. I will update when I get an answer from Orion. William

#22 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 01 October 2013 - 03:51 PM

Which version specifically?

#23 Wmacky

Wmacky

    Surveyor 1

  • *****
  • Posts: 1933
  • Joined: 24 Nov 2007
  • Loc: Florida

Posted 01 October 2013 - 09:09 PM

My CGE does something like that. When doing High magnification planetary imaging my mount will continue to move in the direction of the slew after releasing the button. It will do this for a couple seconds then slowly come to rest. On my mount, this only happens in one direction. In the other the mount stops as soon as the button releases. I was told backlash / balance.

#24 WillCarney

WillCarney

    Apollo

  • *****
  • Posts: 1465
  • Joined: 08 Oct 2009
  • Loc: Bloomington, ILL

Posted 02 October 2013 - 03:31 PM

Which version specifically?


The newest. 3.35
Orion is aware of alignment issues with the newest firmware but does not know when or if it will be fixed. Follow the thread on Orion firmware. I will post any updates as soon as I get them. William

#25 rmollise

rmollise

    Hubble

  • *****
  • Posts: 15693
  • Joined: 06 Jul 2007

Posted 02 October 2013 - 04:40 PM

I would suggest keeping an eye on the SkyWatcher page instead. Orion is always two steps behind on updates for the Synta mounts. FWIW, I've been running 3.35 for a while without a problem...






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics