HEQ5 Pro RA Play during Rowan Mod

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HEQ5 Pro RA Play during Rowan Mod

#1

Post by skysnapper »


I've just done the Rowan belt mod on a few months old HEQ5Pro.
Dec conversion went without problems.

Doing RA, after removing the motor I found about 5 degrees play in the main cog that drives the mount head.
Removing the drive cog and the spindle has that same 5 degrees play.

I assume this will kill me on backlash when I try this against the sky for the first time.
Completed the RA conversion and closed it all up. Now we wait to see if it's a RA backlash bunfight.

Has anyone noticed this during the belt conversion please ?

Thanks
Rig 1: Skymax 127, ASI 183MC Pro/ASI 120MC-S, ASI 120MM-S Guide, HEQ5 Pro, ZWO EAF, Kstars/INDI/EKOS on Ubuntu
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Re: HEQ5 Pro RA Play during Rowan Mod

#2

Post by helicon »


Hello Skysnapper and welcome to the forums.
-Michael
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Re: HEQ5 Pro RA Play during Rowan Mod

#3

Post by Juno16 »


skysnapper wrote: Fri Apr 08, 2022 2:29 pm I've just done the Rowan belt mod on a few months old HEQ5Pro.
Dec conversion went without problems.

Doing RA, after removing the motor I found about 5 degrees play in the main cog that drives the mount head.
Removing the drive cog and the spindle has that same 5 degrees play.

I assume this will kill me on backlash when I try this against the sky for the first time.
Completed the RA conversion and closed it all up. Now we wait to see if it's a RA backlash bunfight.

Has anyone noticed this during the belt conversion please ?

Thanks

Hi skysnapper and welcome to TSS!

I recently preformed the belt mod and everything went as planned. Performance better than I expected. No issue with play in the RA motor/spindle as you mentioned. However, I recently came across a post in Stargazers Lounge that sounds exactly like the issue that you describe.

The poster was working with an earlier HEQ5 and thought that that might be related to the issue that he was having with the modification.

Please check out the post link below and see if his issue is the same as yours. He contacted Rowan and they were fabricating a new spindle for him at no charge.

https://stargazerslounge.com/topic/3930 ... mod-issue/

Best of luck!
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
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My Astrobin: https://www.astrobin.com/users/Juno16/
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Re: HEQ5 Pro RA Play during Rowan Mod

#4

Post by skysnapper »


Thanks Michael and Jim for the kind welcome and quick replies.

I followed your link and read it with interest but I don't think it's the same issue.
If I remove the RA motor and am just left with the spindle that drives the mount's RA axis around then that's the part that has rotational play - the shaft through the mount.

I made a short video but it's 20MB in size so will have to find a way to trim it before sharing.

With the belts reattached it all seems tight but I can't ignore the amount of play that I felt with everything disconnected.

I guess I'll only really know during a session.
Rig 1: Skymax 127, ASI 183MC Pro/ASI 120MC-S, ASI 120MM-S Guide, HEQ5 Pro, ZWO EAF, Kstars/INDI/EKOS on Ubuntu
Rig 2: WO Zenithstar 61 with Flattener 61A, Star Adventurer Pro, Intervalometer
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Re: HEQ5 Pro RA Play during Rowan Mod

#5

Post by Juno16 »


Sounds like you are talking about the RA worm gear shaft???

It still might be a good idea to reach out to Rowan Astronomy.

If there is slack between the RA worm shaft and the Rowan supplied belt pulley, I would think that it would wobble when rotated??

Maybe you can upload the video to a web hosting site and share the link.
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
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Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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Re: HEQ5 Pro RA Play during Rowan Mod

#6

Post by skysnapper »


Hi Jim,

It's in that area.

I've uploaded the short video to Mega - Link here -> https://mega.nz/file/JaJ0DSIJ#YRHwjnqS0 ... DqKYXG6okI
Last edited by skysnapper on Fri Apr 08, 2022 6:24 pm, edited 1 time in total.
Rig 1: Skymax 127, ASI 183MC Pro/ASI 120MC-S, ASI 120MM-S Guide, HEQ5 Pro, ZWO EAF, Kstars/INDI/EKOS on Ubuntu
Rig 2: WO Zenithstar 61 with Flattener 61A, Star Adventurer Pro, Intervalometer
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Re: HEQ5 Pro RA Play during Rowan Mod

#7

Post by skysnapper »


OK so first night to test was last night and although we had a 90% moon I managed 2 hours on NGC 2404 (which is clearly not enough - but the fog called time on activities).

Guiding seems worse than before the rowan mod, particularly in RA (green in the attached image).

I played around with the guide exposure but anything above or below 2 seconds made it worse.
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guiding after rowan mod 3.JPG
Rig 1: Skymax 127, ASI 183MC Pro/ASI 120MC-S, ASI 120MM-S Guide, HEQ5 Pro, ZWO EAF, Kstars/INDI/EKOS on Ubuntu
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Re: HEQ5 Pro RA Play during Rowan Mod

#8

Post by Juno16 »


Hi Skysnapper,

I totally missed your post on 4/8/22. Sorry!

Just a hint, if you use an "at" symbol in front of a member's name, the member will get a notification that they mentioned you. Example: @skysnapper . I just subscribed to this thread so that I can see any posts to it.

The video really shows what you were describing. Play in the RA worm. I can't say, but I wouldn't think that the play (backlash) in the RA worm is related to the changes in your guiding since the Rowan modification. I would think that the RA worm play was there before the mod and can't see how performing the modification could cause that. So, if your guiding took a turn for the worse after the belt modification, I would look look at the modification. Just for curiosity, how was your guiding before the belt mod?

The play (backlash) that you show in your RA worm is a lot, but it is either about the same or maybe just slightly more than what my RA worm had. I moved the gear and not the shaft, so mine might have seemed larger than it would have at the shaft, but I had a lot of play in my RA worm also. I have since adjusted the RA worm backlash (it was kind of a pia). I still have a little bit of play, but nowhere near as much as before. I followed https://www.astro-baby.com/heq5-rebuild/heq5-we1.htm.
I have yet to test the mount with my newly adjusted RA worm backlash, but I got pretty decent results before the adjustment. viewtopic.php?p=195457#p195457

I have had two sessions since the belt modification and DEC worm adjustment (I did both at the same time). Guiding dropped from a average 1.15 total rms error (arcsec) to about 0.7 on a target near the celestial equator and from about 0.9-1.0 pre mod on targets more north to 0.5-0.6 post mod. The only reason that I am mentioning my error rates is to give you an idea what I have experienced so far from the belt modification (and DEC worm adjustment).

So, in my limited experience, I would say that the RA worm play that you show isn't much different from what I had and I got decent guiding numbers. Yes, the RA error was worse than DEC (that is why I went ahead and adjusted the RA worm), but it was still significantly better than before the mod.

I am not familiar with your guiding software (I have only used PHD2), but I get the idea. What kind of numbers did you get before the mod? The total rms error is not good at all, but I have seen worse. Also to note is that your DEC error seems very high also which would have nothing to do with the play in the RA worm that you showed in your video.

Just me, since I saw similar RA worm backlash in my mount after the Rowan belt mod (I'm sure that it was there before too), but still my overall guiding (and error) improved significantly.

Definitely look at the mod and try to troubleshoots there. Maybe check out this forum and others to see what issues others have had with the belt modification. I have read that others have had issues with belt tension and pulley alignment.

Please reply back with your findings. I am really curious what you might find. If you don't have any success, try posting to other forums. I am a member of Cloudy Nights forum, but don't post there often. I have, however, found help there and nowhere else because there membership base is so large. Just an idea.

Good luck!
Last edited by Juno16 on Thu Apr 14, 2022 1:51 pm, edited 1 time in total.
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
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Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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Re: HEQ5 Pro RA Play during Rowan Mod

#9

Post by Juno16 »


Hi again skysnapper,

Try Googling the issue. I found this at Stagazers Lounge as an example. Might not be what’s going on with your mount, but interesting for informational purposes.

https://stargazerslounge.com/topic/3466 ... d-guiding/

Also, I did reduce tension on the DEC bearing as described in this post. I couldn’t balance my small scope easily in DEC because it was very stiff. This easy adjustment helped tremendously.
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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Re: HEQ5 Pro RA Play during Rowan Mod

#10

Post by skysnapper »


Thought I'd replied but seems not.

Thanks Jim (@Juno16) for the quick and in depth reply.

Derek at Rowan Engineering suggested the same - that it's a tolerance detail and part of the manufacturing process. Need to mesh the worm drive closer to the other gears. I followed the process in this link and it is a very very fine tune to get this right.

Now we need a star filled night to test it ;)

(
Rig 1: Skymax 127, ASI 183MC Pro/ASI 120MC-S, ASI 120MM-S Guide, HEQ5 Pro, ZWO EAF, Kstars/INDI/EKOS on Ubuntu
Rig 2: WO Zenithstar 61 with Flattener 61A, Star Adventurer Pro, Intervalometer
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Re: HEQ5 Pro RA Play during Rowan Mod

#11

Post by Juno16 »


skysnapper wrote: Fri Apr 15, 2022 10:21 am Thought I'd replied but seems not.

Thanks Jim (@Juno16) for the quick and in depth reply.

Derek at Rowan Engineering suggested the same - that it's a tolerance detail and part of the manufacturing process. Need to mesh the worm drive closer to the other gears. I followed the process in this link and it is a very very fine tune to get this right.

Now we need a star filled night to test it ;)

(

It sure is a very fine (and finicky) adjustment for RA. Adjusting the DEC worm didn’t seem as tedious as the RA worm.
I’m sure that you saw much less play at the RA shaft post adjustment.

I have yet to test my RA worm adjustment performance yet either. The DEC worm adjustment improved the DEC backlash
tremendously and I recommend that you check/adjust the DEC worm also unless your guiding software reports DEC backlash is minimal.

Thanks for the update and please let me know how it goes.
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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Re: HEQ5 Pro RA Play during Rowan Mod

#12

Post by yobbo89 »


skysnapper wrote: Fri Apr 15, 2022 10:21 am Thought I'd replied but seems not.

Thanks Jim (@Juno16) for the quick and in depth reply.

Derek at Rowan Engineering suggested the same - that it's a tolerance detail and part of the manufacturing process. Need to mesh the worm drive closer to the other gears. I followed the process in this link and it is a very very fine tune to get this right.

Now we need a star filled night to test it ;)

(
ohh yeah hypertuning !, 50 micron gap = exploding bearings, 100 microns = too much pe xd
scopes :gso/bintel f4 12"truss tube, bresser messier ar127s /skywatcher 10'' dob,meade 12'' f10 lx200 sct
cameras : asi 1600mm-c/asi1600mm-c,asi120mc,prostar lp guidecam, nikkon d60, sony a7,asi 290 mm
mounts : eq6 pro/eq8/mesu 200 v2
filters : 2'' astronomik lp/badder lrgb h-a,sII,oIII,h-b,Baader Solar Continuum, chroma 3nm ha,sii,oiii,nii,rgb,lowglow,uv/ir,Thousand Oaks Solar Filter,1.25'' #47 violet,pro planet 742 ir,pro planet 807 ir,pro planet 642 bp ir.
extras : skywatcher f4 aplanatic cc, Baader MPCC MKIII Coma Corrector,Orion Field Flattener,zwo 1.25''adc.starlight maxi 2" 9x filter wheel,tele vue 2x barlow .

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Re: HEQ5 Pro RA Play during Rowan Mod

#13

Post by skysnapper »


Massive massive improvement ! :dance:

Was lucky enough to test just now and guiding staying roughly below 1 arc second.
Thanks to all who pointed me in the right direction - @Juno16, @yobbo89.

now, where to find the adjustment for a removing 90% moon ...
Attachments
guiding after tuning.JPG
Rig 1: Skymax 127, ASI 183MC Pro/ASI 120MC-S, ASI 120MM-S Guide, HEQ5 Pro, ZWO EAF, Kstars/INDI/EKOS on Ubuntu
Rig 2: WO Zenithstar 61 with Flattener 61A, Star Adventurer Pro, Intervalometer
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Re: HEQ5 Pro RA Play during Rowan Mod

#14

Post by Juno16 »


skysnapper wrote: Fri Apr 15, 2022 8:46 pm Massive massive improvement ! :dance:

Was lucky enough to test just now and guiding staying roughly below 1 arc second.
Thanks to all who pointed me in the right direction - @Juno16, @yobbo89.

now, where to find the adjustment for a removing 90% moon ...
Image

Great news!

That might even qualify as a mega massive improvement!

The total RMS guiding error dropped from over 2 arc seconds to about 0.5! Wow! Have fun!
Jim

Scopes: Explore Scientific ED102 APO, Sharpstar 61 EDPH II APO, Samyang 135 F2 (still on the Nikon).
Mount: Skywatcher HEQ5 Pro with Rowan Belt Mod
Stuff: ASI EAF Focus Motor (x2), Orion 50mm Guide Scope, ZWO 30 mm Guide Scope, ASI 220mm min, ASI 120mm mini, Stellarview 0.8 FR/FF, Sharpstar 0.8 FR/FF, Mele Overloock 3C.
Camera/Filters/Software: ASI 533 mc pro, ASI 120mm mini, Orion SSAG, IDAS LPS D-1, Optolong L-Enhance, ZWO UV/IR Cut, N.I.N.A., Green Swamp Server, PHD2, Adobe Photoshop CC, Pixinsight.
Dog and best bud: Jack
Sky: Bortle 6-7
My Astrobin: https://www.astrobin.com/users/Juno16/
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