Dobsonian mount play?

Discuss reflector telescopes
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Dobsonian mount play?

#1

Post by Larry 1969 »


Hello all!

I wasn't sure where to post this so, since dobs are a popular choice for beginners, here it is!
I purchased my scope new (Skywatcher 10" collapsible dob) and have noticed excessive azimuth play. The instructions state to end movements with up and right but sometimes I pass up my object a bit.
At slew speed 5 it takes approximately 10 seconds for the mount to reverse direction and then another 10 seconds to eliminate the play. This hasn't been a huge deal for visual, but I just started taking
pictures and I've noticed serious tracking problems with targets in the north and south. With targets in the east and west I can easily get 20 second exposures but I suffer terrible star trailing in the north
and south.

My thoughts are that tracking targets in the east and west mainly use the alt motor while north and south targets make more use of the azimuth motor...... :think:

Either way, I'd like to eliminate, or significantly reduce the slop in this mount. I'm very mechanically inclined and not afraid to disassemble the base.

Any suggestions as to what can be done?

Thanks!

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
yobbo89 Australia
Moderator
Moderator
Articles: 0
Offline
Posts: 2560
Joined: Sat May 11, 2019 7:44 pm
4
Location: australia qld brisbane
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#2

Post by yobbo89 »


I have no idea where to begin to help you, go to dobs are not ideal for astrophotography,i don't think too many people adventure to improve it.

it might help to also balance the scope with magnets on the back end.
the controller should have a backlash setting as well.
there is a worm adjustment spring but it looks like you have to totally pull apart the go to system

https://stargazerslounge.com/topic/1567 ... uto-mount/
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 .

Image
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#3

Post by Larry 1969 »


Thanks yobbo89!

Yeah. I know dobs aren't good for AP but I wouldn't mind trying to improve it while I save for a better set up.

I did balance the tube with adhesive wheel weights after installing my Moonlight focuser. I actually had to add 4.5 lbs opposite the focuser!

My understanding of the backlash adjustment in the HC is that it alters the initial slew speed to compensate. The lash is still present though.

Thanks for the link! I'm going to look into disassembling the mount.

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
yobbo89 Australia
Moderator
Moderator
Articles: 0
Offline
Posts: 2560
Joined: Sat May 11, 2019 7:44 pm
4
Location: australia qld brisbane
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#4

Post by yobbo89 »


any way have a good read on that link, there is another link in a post there to someone else who has done some tuning ,try and find that post as well, i probably recommend small adjustments on that worm block, maybe 1/4 of a turn,shouldn't be too much of a problem as the thing is spring loaded
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 .

Image
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#5

Post by Larry 1969 »


So, I found this thread about a "lazy Susan mod". https://stargazerslounge.com/topic/1189 ... -dob-base/
I think I'm going to give this a try. It seems that this mod could smooth out my az tracking but I'm still not sure how to eliminate the play.
I just measured it and my base is 20.5" in diameter and there is 1/2" of play when measured at the edge of the base....
Not sure what that translates to in degrees but I feel it's excessive.

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: Dobsonian mount play?

#6

Post by Lady Fraktor »


I just posted this a few days ago for someone at AF: http://www.orion-xt10.com/lazy-susan-az ... aring.html
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#7

Post by Larry 1969 »


That's EXACTLY what I was looking for!
Thanks Lady Fraktor!

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#8

Post by Larry 1969 »


KIMG0093.jpg
So I figured I would lift the motor cover and have a peek at what I'm getting into.
I found this broken piece of ring that I believe is part of a noise suppressor. There is a complete one in the pic also.
I have to assume I only need one of these? Approx 2/3 down the page he gets into stripping the base and I can see one in his pics.

https://stargazerslounge.com/topic/1567 ... uto-mount/
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: Dobsonian mount play?

#9

Post by Lady Fraktor »


That looks like a RF choke. It helps keep electrical pulse noise from interfering with the signals.
You should be able to get a replacement at a electrical supply shop or something like a ham radio shop.
You may not need it though, sometimes they put them on "just in case"
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#10

Post by Larry 1969 »


Thanks!
There is one the wiring passes through in the pic. Is there supposed to be two?
The pics I found online only show one. I think it may have ended up in there by mistake.

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
helicon United States of America
Co-Administrator
Co-Administrator
Articles: 584
Offline
Posts: 12274
Joined: Mon May 06, 2019 1:35 pm
4
Location: Washington
Status:
Offline

TSS Awards Badges

Re: Dobsonian mount play?

#11

Post by helicon »


Gee Larry I hope this gets sorted out.
-Michael
Refractors: ES AR152 f/6.5 Achromat on Twilight II, Celestron 102mm XLT f/9.8 on Celestron Heavy Duty Alt Az mount, KOWA 90mm spotting scope
Binoculars: Celestron SkyMaster 15x70, Bushnell 10x50
Eyepieces: Various, GSO Superview, 9mm Plossl, Celestron 25mm Plossl
Camera: ZWO ASI 120
Naked Eye: Two Eyeballs
Latitude: 48.7229° N
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#12

Post by Larry 1969 »


Thanks Helicon. I'm sure it'll be OK.
I did hear something rattling around in the base when I first got it but I didn't want to take it apart.

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#13

Post by Larry 1969 »


So, I'm concerned about the quality of lazy Susan bearing to get. Amazon and eBay have offerings but the reviews always say something about them being noisy or notchy movement.
I came across this and wonder if anyone has any success with it. https://www.teleskop-express.de/shop/pr ... 6#ebericht

It's in German but it seems made for this.

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: Dobsonian mount play?

#14

Post by notFritzArgelander »


Larry 1969 wrote: Wed Sep 04, 2019 12:44 am So, I'm concerned about the quality of lazy Susan bearing to get. Amazon and eBay have offerings but the reviews always say something about them being noisy or notchy movement.
I came across this and wonder if anyone has any success with it. https://www.teleskop-express.de/shop/pr ... 6#ebericht

It's in German but it seems made for this.

Larry
I've dealt with them on exotic optical accessories very happily.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#15

Post by Larry 1969 »


notFritzArgelander wrote: Wed Sep 04, 2019 1:03 am
I've dealt with them on exotic optical accessories very happily.
Thanks! Do you have any experience with this particular bearing?

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: Dobsonian mount play?

#16

Post by notFritzArgelander »


Larry 1969 wrote: Wed Sep 04, 2019 1:16 am
notFritzArgelander wrote: Wed Sep 04, 2019 1:03 am
I've dealt with them on exotic optical accessories very happily.
Thanks! Do you have any experience with this particular bearing?

Larry
It looks like the bearing I have on Z12. I recently replaced it since my Dob base was damaged in a long distance move. My base is purely manual and I'm happy with it. YMMV though.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
User avatar
Lady Fraktor Slovakia
Co-Administrator
Co-Administrator
Articles: 0
Offline
Posts: 9860
Joined: Mon Apr 29, 2019 9:14 pm
4
Location: Slovakia
Status:
Offline

Re: Dobsonian mount play?

#17

Post by Lady Fraktor »


There is a British flag top right that changes the site to English: https://www.teleskop-express.de/shop/pr ... ts_id/1646

I have no experience with the bearing you are looking at but have dealt with TS many times over the years.
An excellent company to buy from. Quite a few people in the USA order from them as well.

Give the mount a try with the one RF choke, it probably really only needs the one if any.
Sometimes they put them on just in case but the voltage/ signal going through the wires is going to be very tiny as it is.
See Far Sticks: Antares Elita 103/1575, AOM FLT 105/1000, Bresser BV 127/1200, Nočný stopár 152/1200, Vyrobené doma 70/700, Stellarvue NHNG DX 80/552, TAL RS100/1000, Vixen SD115s/885
EQ: TAL MT-1, Vixen SXP, AXJ, AXD
Az/Alt: AYO Digi II/ Argo Navis, Stellarvue M2C/ Argo Navis
Tripods: Berlebach Planet (2), Uni 28 Astro, Report 372, TAL factory maple, Vixen ASG-CB90, Vixen AXD-TR102
Diagonals: Astro-Physics, Baader Amici, Baader Herschel, iStar Blue, Stellarvue DX, Takahashi prism, TAL, Vixen flip mirror
Eyepieces: Antares to Zeiss
The only culture I have is from yogurt
My day was going well until... people
Image
User avatar
notFritzArgelander
In Memory
In Memory
Articles: 0
Offline
Posts: 14925
Joined: Fri May 10, 2019 4:13 pm
4
Location: Idaho US
Status:
Offline

TSS Awards Badges

Re: Dobsonian mount play?

#18

Post by notFritzArgelander »


Lady Fraktor wrote: Wed Sep 04, 2019 5:18 am There is a British flag top right that changes the site to English: https://www.teleskop-express.de/shop/pr ... ts_id/1646

I have no experience with the bearing you are looking at but have dealt with TS many times over the years.
An excellent company to buy from. Quite a few people in the USA order from them as well.

Give the mount a try with the one RF choke, it probably really only needs the one if any.
Sometimes they put them on just in case but the voltage/ signal going through the wires is going to be very tiny as it is.
That makes sense to me.
Scopes: Refs: Orion ST80, SV 80EDA f7, TS 102ED f11 Newts: AWB 130mm, f5, Z12 f5; Cats: VMC110L, Intes MK66,VMC200L f9.75 EPs: KK Fujiyama Orthoscopics, 2x Vixen NPLs (40-6mm) and BCOs, Baader Mark IV zooms, TV Panoptics, Delos, Plossl 32-8mm. Mixed brand Masuyama/Astroplans Binoculars: Nikon Aculon 10x50, Celestron 15x70, Baader Maxbright. Mounts: Star Seeker IV, Vixen Porta II, Celestron CG5
User avatar
Larry 1969 United States of America
Milky Way Ambassador
Articles: 0
Offline
Posts: 1481
Joined: Fri May 17, 2019 12:33 am
4
Location: Pittsburgh PA USA
Status:
Offline

TSS Photo of the Day

Re: Dobsonian mount play?

#19

Post by Larry 1969 »


Thanks!
I saw the Brit flag and it translated for me.
I might give that bearing a try.

Larry
For visual:
10" Skywatcher collapsible goto dob, various EP's and a Celestron StarSense auto align.

For imaging:
Orion 8" astrograph 800mm @ F3.9
Eq6-R Pro controlled by APT via EQmod with an OTA mounted mini PC
Tele Vue Paracorr Type 2 coma corrector
Altair Hypercam 26C
Image
User avatar
man1
Moon Ambassador
Articles: 0
Offline
Posts: 74
Joined: Mon Sep 09, 2019 7:58 am
4
Location: Canada
Status:
Offline

Re: Dobsonian mount play?

#20

Post by man1 »


Hi Larry,
I have a XT10i on order and will install a 'Lazy Susan' right from the start. My version will be motorized and will work just like a motorized focuser. I will have variable speed, but I don't have the need of an optical encoder... since all I want is a very smooth turning of the telescope without touching and bumping it. The final drive is a worm drive that is run by a geared motor 3000:1 at 0.5 RPM. There will be a quick disconnect, so that I can steer the scope by hand and get it into position.
The 'Lazy Susan' to get is from Lee Valley --> http://www.leevalley.com/us/wood/page.a ... 3298,43316 . There is no play and this version runs very smooth. I have purchased it already and I am more than happy with that version. Extremely well made!!! It costs a bit more - then again you get what you pay for.

Hope this helps.....
Cheers, man1
Orion XT10i custom, Orion GiantView BT-70, Bushnell Natureview 20-60x65, Barska 25-125x80
SkySafari6 Pro & 7 Pro, SkyFi 3, ASI290MC, T7C
Post Reply

Create an account or sign in to join the discussion

You need to be a member in order to post a reply

Create an account

Not a member? register to join our community
Members can start their own topics & subscribe to topics
It’s free and only takes a minute

Register

Sign in

Return to “Reflector Telescopes”