HEQ5 ROWAN BELT BAD GUIDING

[Kostas P]

Hello!.

 I want to ask you a question. I HEQ5 with rowan belt and a ed80 with ASI 183mc pro, i have my guide scope piggyback and my guiding is terrible..... total error 1,6" to 3" some times. can you share me some tips or your settings in PHD? maybe my tension on belt is wrong or something? The balance it seems ok... but the mount is a bit stif in free movement. before a was having a 150PDS with no so much problem.... I polar aling with sharpcap.. I calibrate close to equator and was using the guide assistant. not much luck...

thanks!!!!!

PHD2_GuideLog_2020-01-09_185027.txt

[alacant]

1 hour ago, Kostas P said:

the mount is a bit stif in free movement

Hi

DEC is sticking. Loosen the cone bearing at the base of DEC and slacken the worm to gear mesh. That should get you closer.

HTH

 

[Kostas P]

thanks for your reply.

do you mean this?

http://www.astro-baby.com/heq5-rebuild/heq5-we1.htm

or the cone base that is close to the weight? is there any other guide?

[wimvb]

1 hour ago, Kostas P said:

thanks for your reply.

do you mean this?

http://www.astro-baby.com/heq5-rebuild/heq5-we1.htm

or the cone base that is close to the weight? is there any other guide?

Astro-Baby's guide is the best, imo. Start with the easiest part: adjusting the worm gear. If that helps, you're ok. While you adjust the worm gear, constantly wiggle the dec axis to find where it moves free enough but doesn't have backlash.

If adjustment of the worm gear isn't enough, you may need this:

http://www.astro-baby.com/heq5-rebuild/heq5-d1.htm

I've done a strip down and aRowan modification on a HEQ5 for a friend, and taking this mount apart is straight forward with the help of the guide. But ther's no need to strip down more than is absolutely necessary. Especially if you're not familiar with this kind of work.

[Kostas P]

5 minutes ago, wimvb said:

Astro-Baby's guide is the best, imo. Start with the easiest part: adjusting the worm gear. If that helps, you're ok. While you adjust the worm gear, constantly wiggle the dec axis to find where it moves free enough but doesn't have backlash.

If adjustment of the worm gear isn't enough, you may need this:

http://www.astro-baby.com/heq5-rebuild/heq5-d1.htm

I've done a strip down and aRowan modification on a HEQ5 for a friend, and taking this mount apart is straight forward with the help of the guide. But ther's no need to strip down more than is absolutely necessary. Especially if you're not familiar with this kind of work.

Thanks!!! and how is your friends guiding?

[alacant]

3 hours ago, Kostas P said:

do you mean this?

Hi 

No. That's overkill. You simply need this bit...

...from here. No need to fully dismantle the DEC axis, Just remove the counterweight support to reveal the bush which holds the bearing in place. Clean and regrease it whilst you're there.

Then follow this for the worm mesh.

HTH

[Kostas P]

Wow!! guys i done what you suggest me also the ra belt was a litle loose.. and look at this beauty!!

thanks so much guys!!!!

 

 

[wimvb]

23 hours ago, Kostas P said:

Thanks!!! and how is your friends guiding?

That was just before he sold the mount. It also had some stiffness/smooth running issues, which we resolved. Furthermore, he used an SBig autoguider which doesn't produce statistics. He could only see guiding issues in the star profiles of his subs. 

[Dan13]

On 10/01/2020 at 10:54, wimvb said:

While you adjust the worm gear, constantly wiggle the dec axis to find where it moves free enough

Hi, I'm really struggling with mine atm but I've noticed you say "free enough" . I have the ra axis free spinning in ever direction except one part when its not exactly stiff and its more of movement to turn. Does this need to be conpleltley free? As in when the clutch is off? 

 

I ask becusse I'm certain everything else seems to move fine ( belt cog and ra when clutch is on) but there is a little stiffness when the clutch is off at a certain point, is this acceptable?

Many thanks 

[wimvb]

With these "budget" mounts, there will always be a trade off between slight backlash and slight uneven movement. If the mount runs free for one complete rotation of the axis, you're very likely to have backlash. I would accept some uneveness. In the end, your guiding statistics and star shapes will tell you if you need to adjust more or not.

[Dan13]

10 hours ago, wimvb said:

With these "budget" mounts, there will always be a trade off between slight backlash and slight uneven movement. If the mount runs free for one complete rotation of the axis, you're very likely to have backlash. I would accept some uneveness. In the end, your guiding statistics and star shapes will tell you if you need to adjust more or not.

Thank you,  its more so for my knowledge while trying to adjust the worm gears after strip down. Its bloody hard to say "yep thats right" when you don't know what right is if that makes sense! 

 

I have a tiny bit of stiffness in the RA head when moved with my finger but then the cog seems a little too slack maybe but not slipping. It could be fine but I dont know what its meant to be like

[wimvb]

13 hours ago, Dan13 said:

but I dont know what its meant to be like

There's only one way to find ou: test it. 🙂

[JamesF]

22 minutes ago, wimvb said:

There's only one way to find ou: test it. 🙂

Has anyone else got a Harry Hill thing happening at this point?  (Perhaps not anyone who doesn't live in the UK

James

[wimvb]

27 minutes ago, JamesF said:

Has anyone else got a Harry Hill thing happening at this point?

No. Not even after googling.

27 minutes ago, JamesF said:

Perhaps not anyone who doesn't live in the UK

That must be why.

😉

 

Edited July 18, 2020 by wimvb

[Martin AB Cohen]

Hi guys.  I'm new to this forum.  I have an HEQ5 and have a Rowan Belt mod.  I have experienced a stretched belt (my fault!) causing terrible guiding, but DEC backlash is one of a number of major culprits. I see that's what this turned out to be for you on this occasion.  Yes, there is a VERY fine line between backlash and binding on the DEC worm!  By making VERY small adjustments I eventually found a sweet spot where I could not feel any backlash and the DEC would run the full 360 degrees without obvious binding.  One thing I found was that you should not loosen the three DEC carrier bolts very far....just enough so that the carrier can move when you turn the grub screws, as the Astro-baby site rightly advises.  Also, when you have made an adjustment, tighten the three carrier screws a little bit at a time in turn around the three screws until they are all tight, and then test for backlash and binding.  It took some patience but I was very happy when it was done as my guiding troubles disappeared...I even got 0.58" at one point which is a first for my mount!  Was so pleased I wish I'd done it sooner.

[knobby]

Welcome Martin, it's great to see a new member posting positive / useful information.

Wishing you clear skies.

[Martin AB Cohen]

Thanks for that.

[Martin AB Cohen]

Can you tell me where to find the current imaging challenge?  I might like to have a go!