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Sky-Watcher Esprit 80 focuser is kinda loose

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#1 NMBob

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Posted 01 March 2016 - 01:32 PM

Other than using the focus lock is there any way to tighten up the focus adjustment a bit overall? I looked over the set screws, but they don't seem to do it. It's not wobbly loose, but 'hang something on it and watch it extend' loose. Some kind of damping grease? I was thinking of just winding some yarn around the shaft between one of the knobs and the body. Fishing line! I KNOW how well that works on getting a boat motor to slow down. :)

 

Thanks!

 

Bob

 



#2 Tim

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Posted 01 March 2016 - 09:05 PM

Hi my 80 is outside and its a bit of a blizzard at the moment or I would look.. I have had this issue with either the 80 or the 120mm Esprit it was a screw in the middle if I am not mistaken. I turned it 1/2 turn maybe a bit more and it made all the difference.  Sorry I can't give you more specifics but should be an easy fix once you fine the correct screw to turn.


Edited by Tim, 01 March 2016 - 09:06 PM.


#3 NMBob

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Posted 01 March 2016 - 11:39 PM

Hi Tim!

 

Boy I miss winter. We don't really get much of it here on the Rio Grande.

 

I think I just found it when I went looking for the screws in the center. No where near the knobs (like on my Lunt's FeatherTouch) are four set screws on focuser body/outer tube. Two forward near two of the screws that are holding the focuser to the rest of the telescope, and two near the rear of the outer tube on either side of the focus lock. They were all partially screwed in and loose. I ran them all in until they started getting tight then backed them out a bit at a time. Fixed! Not at all what I was expecting. :)

 

Well stay warm up there. Drink plenty of hot chocolate and vodka (some brands make a mint taste if you just put a cap full into the mug).

 

Thanks!

 

Bob


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#4 Tim

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Posted 02 March 2016 - 04:02 PM

Hi Bob

 

happy to help out, glad it was an easy fix! I was surprised when I had the issue and then how easy of a fix it was..  Mint Vodka sounds interesting I'll have to give it a try!


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#5 Stamos

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Posted 16 September 2016 - 09:20 AM

Hello!

Yesterday it was delivered to me my brand new SW Esprit80. I'm very happy but the focuser obviously needs adjustment...

It cannot hold my dslr (with its cooler) without slipping. Before i start screwing-unscrewing the bolts under the focuser can you please tell me which ones need tightening?

 

20160916_142930_zpsfdc6dofu.jpg


Edited by Stamos, 16 September 2016 - 09:29 AM.


#6 NMBob

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Posted 16 September 2016 - 10:02 AM

I'll look this weekend, but it's not any of those. It's one of the sets of three screws around the circumference of the focuser tube itself. Like the two to the left of hole 3 and the one to the right of hole 4 in your picture. I think it was the set of three that are along the back edge where the focuser lock is.



#7 skyward_eyes

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Posted 16 September 2016 - 11:22 AM

Do not touch any of the bottom screws listed in that picture. None of them will adjust the focuser tension. 

 

The Esprit focus has two pads located 90 degrees apart from one another. Sometimes during shipping these pressure pads can become a little loose. Not to worry because they can be adjusted by slightly tightening their mounting screws. Please see the attached picture. 

 

One thing to note is that the pads inside the focuser are mount actually mounted. They are kept in place by the two adjustment screws and the pressure from being pressed into the drawtube. Be careful not to loosen the adjustment screws to much because the pads will fall out of place and are a HUGE pain to put back into place.

 

 

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  • EspritFocuser.jpg

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#8 Stamos

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Posted 16 September 2016 - 01:46 PM

Ok guys, mission accomplished.

I tightened those 4 screws (two pairs) until i felt some resistance and now the focuser is rock solid. 

Its a little bit tight when turning the knobs but i prefer it like this as long as nothing gets damaged...



#9 NMBob

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Posted 16 September 2016 - 02:46 PM

I didn't even know there were "pads". I was having nightmares about metal-on-metal. Maybe I'll tighten mine up a bit too. :)



#10 tonyt

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Posted 16 September 2016 - 07:01 PM

Tim, the early esprits had a different focuser to the current production so the focuser adjustments are different.

 

Stamos, here's a pic showing what the screws on the pinion assembly are for. The outer 4 hold the assembly to the focuser body and the 4 adjacent grub screws push against the focuser body - this push/pull arrangement allows proper meshing of the pinion with the rack.

other holes allow access to the grub screws holding the knobs onto the pinion shaft.

 

Poorly adjusted focusers are common on new esprits.

NOTE: if you disassembly the focuser don't pull the drawtube out of the focuser body past it's normal range - parts inside can fall out of place. 

 

post-86253-0-42669500-1471909602_thumb1.jpg



#11 skyward_eyes

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Posted 16 September 2016 - 09:53 PM

Please avoid pulling the draw tube out of its housing. The upper rail of the focus (found stop the draw tube) sits in a linear bearing. The bearing is comprised of over 40 very small 1mm metal bearing. They will go everywhere if you pull the draw tube out and are a major pain to get back in place.

#12 ronhal

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Posted 21 September 2016 - 10:42 AM

Hi, I am also having this problem with an early version of SW 80 ED. ( the blue one).  I gently adjusted the screws but It did not fix.  The draw tube would not retract all the way back into the OTA.  Backed off a bit on the screws and the draw tube goes back in.  What to do?



#13 astrobug BE

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Posted 18 June 2018 - 10:46 AM

I have some play in the micro focuser. Should I reduce the distance between the rack & pinion?



#14 DaveN

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Posted 04 April 2019 - 04:12 AM

hi gang

 

Jump forward a couple of years to March 2019 and I took delivery of my new ESPRIT 100ED

 

waited 3 weeks for the first clear nite to try it out and to my disappointment I discovered that there was movement in the FOV

when the focusser was turned in and out. Stars would jump one way or the other depending on which way the focusser was turned.

 

The comments that @skyward_eyes made in post #7 were spot on for correcting the problem ....  I discovered the solution before I

saw this thread.

 

skyward_eyes, on 17 Sept 2016 - 03:22 AM, said:

Do not touch any of the bottom screws listed in that picture. None of them will adjust the focuser tension.

The Esprit focus has two pads located 90 degrees apart from one another. Sometimes during shipping these pressure pads can become a little loose. Not to worry because they can be adjusted by slightly tightening their mounting screws. Please see the attached picture.

 

 

 

Just wanted to let people know that loose focussing mechanisms still seem to be an issue with new ESPRIT scopes ... not very good

for something that cost AU$3500  frown.gif

 

 

Regards

Dave


Edited by DaveN, 04 April 2019 - 04:15 AM.

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#15 dmoon2208

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Posted 08 May 2019 - 04:47 PM

Please avoid pulling the draw tube out of its housing. The upper rail of the focus (found stop the draw tube) sits in a linear bearing. The bearing is comprised of over 40 very small 1mm metal bearing. They will go everywhere if you pull the draw tube out and are a major pain to get back in place.

I was wondering why the focuser on my ESPRIT 100ED all of a sudden had a lot of resistance, heard rattling sounds and a few of the bearing fell out of my tube. Now I know where they are from. Is losing a few a concern? If i were to replace them, what do I need to unscrew to pull out the draw tube?

 

Thanks David



#16 skyward_eyes

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Posted 08 May 2019 - 05:18 PM

I was wondering why the focuser on my ESPRIT 100ED all of a sudden had a lot of resistance, heard rattling sounds and a few of the bearing fell out of my tube. Now I know where they are from. Is losing a few a concern? If i were to replace them, what do I need to unscrew to pull out the draw tube?

 

Thanks David

 These should not have come out. The only way these come out is if they are forced out by the rail up top. '

 

Is the drawtube really loose and shifting around within the focuser housing? Reinstalling these is incredibly difficult and leave room for more small bearings to come loose. I would highly discourage you from removing the drawtube from the focuser housing. It should work without them but they should not becoming out without some kind of reasoning. 

 

I have never had one do this before out in the wild. 



#17 dmoon2208

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Posted 08 May 2019 - 08:12 PM

Everything seems very tight and the focusing is still very smooth. Hopefully if was only those four that have somehow forced there way out. Thanks



#18 John Turley

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Posted 22 April 2020 - 11:24 AM

Do not touch any of the bottom screws listed in that picture. None of them will adjust the focuser tension. 

 

The Esprit focus has two pads located 90 degrees apart from one another. Sometimes during shipping these pressure pads can become a little loose. Not to worry because they can be adjusted by slightly tightening their mounting screws. Please see the attached picture. 

 

One thing to note is that the pads inside the focuser are mount actually mounted. They are kept in place by the two adjustment screws and the pressure from being pressed into the drawtube. Be careful not to loosen the adjustment screws to much because the pads will fall out of place and are a HUGE pain to put back into place.

Hi Skyward Eyes

 

Do you know what size Allen key I need for the screws in the picture, I have quite a full range but none of them seem to fit.

 

I find that when my Esprit is in a near vertical position, the focuser racks out on its own, I can stop this from happening by applying some tension with the locking lever, but I didn't think it was intended to be used for this purpose, and the manual gives the impression.that it should either be fully locked or fully released.

 

In addition partly locking the focuser appears to introduce backlash.

 

John Turley 



#19 Fernando134

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Posted 23 April 2020 - 04:57 PM

Do not touch any of the bottom screws listed in that picture. None of them will adjust the focuser tension. 

 

The Esprit focus has two pads located 90 degrees apart from one another. Sometimes during shipping these pressure pads can become a little loose. Not to worry because they can be adjusted by slightly tightening their mounting screws. Please see the attached picture. 

 

One thing to note is that the pads inside the focuser are mount actually mounted. They are kept in place by the two adjustment screws and the pressure from being pressed into the drawtube. Be careful not to loosen the adjustment screws to much because the pads will fall out of place and are a HUGE pain to put back into place.

I will take advantage of the thread and ask you a related question: I just realized that one of the mounting screws holding the pads are missing in my Esprit 120. Is it possible for you to send me the screw specification in order I may  get a replacement?

 

Thanks in advance.

 

 

 



#20 John Turley

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Posted 11 June 2020 - 10:39 AM

Do not touch any of the bottom screws listed in that picture. None of them will adjust the focuser tension. 

 

The Esprit focus has two pads located 90 degrees apart from one another. Sometimes during shipping these pressure pads can become a little loose. Not to worry because they can be adjusted by slightly tightening their mounting screws. Please see the attached picture. 

 

One thing to note is that the pads inside the focuser are mount actually mounted. They are kept in place by the two adjustment screws and the pressure from being pressed into the drawtube. Be careful not to loosen the adjustment screws to much because the pads will fall out of place and are a HUGE pain to put back into place. Touchwood I have now managed to sort out the problem.

Touchwood I have now manged to sort out the problem with my Esprit 150. 

 

Originally I could not find an Allen key to fit, First Light Optics in the UK suggested that it might be a 2mm one, but that the adjustment screws might be glued in position. and after giving them a squirt with WD40, and then applying some heat with a hairdryer, I managed to get them to turn. Only a minute amount of turning (less than about one sixteenth of a turn), was required to tighten up the barrel sufficiently so that when the scope was in a near vertical position, the focuser did not slip even with my heaviest eyepiece ( a ES 24 mm 82 degree) inserted, and the fine focus knob would work in both directions. I tried to apply the pressure as evenly as possible between the 4 screws so as not to affect the collimation, and was also careful not loosen the adjustment screws too much in case the pressure pads fell out.

 

I found that if I prevented slipping by applying some tension with the locking lever, then the fine focus would only work in the outward or downwards direction, and was worried that doing this could possibly damage the mechanism.

 

It’s a pity that there is no information in the manual about adjusting the focuser, as I gather poorly adjusted focusers are common on new Esprits, for comparison the focuser on my ES 127 Refractor has 3 large knurled knobs for adjusting the tension.

 

John 


Edited by John Turley, 11 June 2020 - 10:46 AM.


#21 russell23

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Posted 11 June 2020 - 10:57 AM

I wish Skywatcher would upgrade their stock focusers to something more like what is on the Williams optics and Astrotech scopes.   You should not buy a scope as expensive as the Esprit and have to deal with any focuser issue at all.


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#22 AdamJ

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Posted 11 June 2020 - 11:30 AM

I would say that the esprit focuser is better than those you meantioned. SW just don't adjust it correctly before shipping in in many cases.

#23 russell23

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Posted 11 June 2020 - 11:59 AM

I would say that the esprit focuser is better than those you meantioned. SW just don't adjust it correctly before shipping in in many cases.

The focuser on the Williams Optics Z61 APO might be the best I have ever used.  I liked it more than the Moonlite I put on my SW120ED.  The AT focuser is just about as smooth and sturdy.

 

It is true that SW doesn't seem to do a good job of adjusting these focusers before sending them out.  But in the case of the ED Pro line focusers the adjustment is very finicky.  I had to send mine back to get it properly adjusted because it was a horrible mess when I received it new.  And I was unable to get it working properly even following the directions online.

 

The Williams optics, Astrotech, and Stellarvue APOs I have purchased with the 2" and 2.5" R&P focusers have come properly adjusted and smooth.  They also can handle more weight than the stock synta crayford. 

 

I can see the Esprit focuser seems to have a better design than the crayford, but from what I see in this thread adjusting these things is touchier than it should be.
 


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#24 rofus

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Posted 21 November 2020 - 04:24 AM

Fast forward to end of 2020....just received by Esprit120, and with a 3.5kg imaging setup, there’s slipping with the fine focusing knob.

 

If scope is pointing up to the sky, fine knob ‘looses’ some turns and is unable to rack back the focuser. I discovered it as the Sesto Senso was not smoothly racking back the focuser.

 

The coarse knobs work perfectly, so adjusting those 4 tension screws is what fixes the fine knob problem? It seems strange as they probably are for the overall focuser, and I need to adjust only the fine focusing.

 

Disassembling the fine/coarse knob, I see the ball bearings, and if I turn the fine knob, when it looses rounds I can see the ball bearings move but they don’t “grip” enough so they don’t turn always the focuser if vertical, but they roll.

 

I tried adjusting the grub screw that is immediately near the knobs (not part of the four screws holding the scope base), it affects somehow the fine focusing knob but it justl slips, there’s no right setting achievable. It works if scope is not vertical.

 

I posted also on SGL with a picture (cannot upload here as image is too big), any idea?

https://stargazerslo...ocuser-as-well/


Edited by rofus, 21 November 2020 - 04:24 AM.


#25 SimonMiller

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Posted 24 November 2020 - 03:51 PM

Fast forward to end of 2020....just received by Esprit120, and with a 3.5kg imaging setup, there’s slipping with the fine focusing knob.

 

If scope is pointing up to the sky, fine knob ‘looses’ some turns and is unable to rack back the focuser. I discovered it as the Sesto Senso was not smoothly racking back the focuser.

 

The coarse knobs work perfectly, so adjusting those 4 tension screws is what fixes the fine knob problem? It seems strange as they probably are for the overall focuser, and I need to adjust only the fine focusing.

 

Disassembling the fine/coarse knob, I see the ball bearings, and if I turn the fine knob, when it looses rounds I can see the ball bearings move but they don’t “grip” enough so they don’t turn always the focuser if vertical, but they roll.

 

I tried adjusting the grub screw that is immediately near the knobs (not part of the four screws holding the scope base), it affects somehow the fine focusing knob but it justl slips, there’s no right setting achievable. It works if scope is not vertical.

 

I posted also on SGL with a picture (cannot upload here as image is too big), any idea?

https://stargazerslo...ocuser-as-well/

I have just received a Primaluce Lab Sesto Senso 2 Focuser. It didn't work out for me (using an Esprit 100) and I'm returning it to get a Pegasus Dual Motor Focus Controller DMFC and two Pegasus Motor Focus Kit V2 (universal and SCT).

  1. Senso ASCOM driver doesn't show the temperature correctly like the Windows App does;
  2. Senso ASCOM driver doesn't seem to work well with APT and it crashes it frequently;
  3. Senso cannot prevent the focuser slipping back over time when pointing at Zenith;
  4. Senso presets are worthless IMHO as they cannot be relied upon;
  5. Increasing the current can help (but not solve) the slipping but some users have had the units fail as a result (just when the warranty has run out too);
  6. Senso doesn't have a gearbox e.g. no 120:1 gearing which brakes the focuser (improves it);
  7. Senso uses micro-steps. Each micro-step reduces holding torque e.g. much less braking with 2 or 4, almost none with 16-64!
  8. Senso counts steps but the position will not be exact and slips back towards the Zenith;

I was attracted the Primaluce Lab Senso because it "looks nice" and doesn't need a bracket to hold it in place. It should "work", but my limited experience it falls too far short of what is required...

 

I noticed that the Senso counts pulses but can't be guaranteed to reach the actual distance. It doesn't have any "backlash" because it's directly coupled but if it doesn't reach the required destination then it very much "misses the target" and the presets cannot be relied upon. Over time it will slip back and require recalibration. The software provides for this (as a fix up IMHO).

 

The Senso Windows Application has some "quirks" e.g. the Up and Down buttons won't always respond but putting a value and clicking move will respond. Saving Presets doesn't always work.

 

The Senso with ASCOM the driver doesn't correctly report temperatures e.g. it always shows a fixed (negative) temperature even indoors at 20 C.

 

Perhaps by V3 or V4, Primaluce will have the opportunity to resolve some of these issues. IT is worth noting that the Senso doesn't use a gearbox. The cost of a gearbox can be greater than a Servo Motor but it is perhaps a false economy not to use one.

 

NB the Pegasus Motor Controller uses a 1:120 gearbox. The motor provides tension even when switched off that increases 1:120 and prevents rotation. The Senso uses a current to hold current position. When pointed at the Zenith it can slip back so focus points are NOT consistent.

 

One other difference is the Pegasus Motor Controller can be used with several motors. It attaches to the Mini Focuser and not to the Micro Focuser. The Senso uses the 10:1 Mini/Micro gearing of the focuser so using it manually offers some resistance but far less than a gearbox can. The Pegasus Motor Controller provides 10:1 and 1:1 rotary control (what you want) or the shaft can be completely decoupled for complete manual operation. It is also possible to use the Pegasus Motor Controller with many other motors e.g. a Lakeside unit.

 

There is also a Pegasus "all in one" Focus Cube V2. It has the same motor and gearbox as the Motor Focus Kit and can easily lift 6kg when pointed at the Zenith which is an increase on the V1 (4+ kg advertised). This can be a good solution for a one scope setup, but for more than one scope it makes sense to share a Motor Controller. The manual rotary control is a separate box with Focus Cube but integrated with the DMFC.

 

Simon


Edited by SimonMiller, 25 November 2020 - 09:02 AM.



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