Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Fixing the Twilight 1, VersaGo III, AT Voyager 2

  • Please log in to reply
34 replies to this topic

#1 MrJones

MrJones

    Vanguard

  • *****
  • topic starter
  • Posts: 2431
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 02 March 2017 - 12:29 PM

I am still seeing many complaints about this mount, for example that an 80mm refractor overtaxed it. It should be fine with 10lbs and a not-too-long scope and mine is now sturdy enough to probably be alright with up to 15lbs.

 

There are 3 main adjustments or mods I have done (to my VG 3):

 

1) The collar set screws (alt and az pairs) were loose and this allowed much slop in both dimensions. Simply tightening these helped a lot. They are the little black screws in the first photo.

 

2) The other main issue is the cast metal arm is not stiff enough and greatly prolongs vibration settling. Some people have bolted metal plates to it, but after some fooling around I found that just wedging a wood block in the upper gap made a considerable improvement with this problem. See next photo.

 

3) Finally, this is more obvious, tighten the spreader collar. The metal colored one right under the spreader. Then tighten it some more. And maybe again.

 

I also took everything apart and regreased but I'm not sure they really helped much. I still have a very little, barely noticeable, play in the az dimension but my alt is nice and firm.

 

Thanks to all the bad weather for allowing me to have the time to develop these improvements over the past several months. Please feel free to post more better ideas!

Attached Thumbnails

  • twi1.jpg
  • twi2.jpg
  • twi3.jpg

Edited by MrJones, 02 March 2017 - 02:11 PM.

  • stevew likes this

#2 Greyhaven

Greyhaven

    Skylab

  • *****
  • Posts: 4140
  • Joined: 11 May 2004

Posted 02 March 2017 - 01:28 PM

Thanks for the insights on this mount. I have a SW80 ED pro that is on my AVX but I have been thinking of one of these for times when I leave the observatory. kind of sad that these are not good to go even with such light scopes without "home brew" refinements. I mean no disrespect of your solutions, they are well done. It just seems as if the manufacturers just won't do more to supply more than the minimum fit and finish. $200.00 should get you a solid manual alt/az mount... 

Grey


  • Zigarro likes this

#3 evan9162

evan9162

    Surveyor 1

  • *****
  • Posts: 1524
  • Joined: 20 Sep 2013
  • Loc: ID

Posted 02 March 2017 - 01:33 PM


3) Finally, this is more obvious, tighten the spreader collar. The metal colored one right under the spreader. Then tighten it some more. And maybe again.

 

Better yet, swap the two handles.  It never made sense to me that the tiny hand knob was used to tighten the spreader; while the giant, two bar hand wheel is used to attach the mount head to the tripod.

 

I swapped the two around, and now the giant bar serves its proper purpose.


  • jcj380 and Zigarro like this

#4 evan9162

evan9162

    Surveyor 1

  • *****
  • Posts: 1524
  • Joined: 20 Sep 2013
  • Loc: ID

Posted 02 March 2017 - 01:36 PM


1) The collar set screws (alt and az pairs) were loose and this allowed much slop in both dimensions. Simply tightening these helped a lot. They are the little black screws in the first photo.

 

These grub screws hold the worm gear support bushings in place.  They serve to keep them from moving laterally, as well as rotating.  Laterally is obvious, but rotating not so much - the bushings are eccentric, so you adjust the worm mesh by rotating the bushings in the worm block.  This moves the worm closer or farther from the worm wheel.

 

Oh, and BTW, there are two sets of these screws - the other are hidden under a glued-on cover plate on the other side of the worm block.  If you decide to disassemble the worm assembly (or even adjust the worm mesh), you need to loosen those as well or you won't get very far...


Edited by evan9162, 02 March 2017 - 01:37 PM.

  • MrJones likes this

#5 MarkMittlesteadt

MarkMittlesteadt

    Vanguard

  • *****
  • Posts: 2005
  • Joined: 08 Oct 2013
  • Loc: Rothschild, WI. USA

Posted 02 March 2017 - 01:42 PM

This is what I did to mod my Twilight I mount. 

EDIT: My mods to the arm were extremely inexpensive, using only PVC, wood and screws, and a little time...and were very easy to do. The pier extension was easy too, although maybe not necessary for many. The turnbuckles for the legs do help if you find yourself having to extend the lower legs much because they contribute to vibrations almost as much as the arm itself when fully extended. 

 

mount-done.jpg

 

mounthead-done.jpg

 

And I could still view at zenith...

 

vertical.jpg


Edited by MarkMittlesteadt, 02 March 2017 - 02:27 PM.

  • Jon Isaacs and rogan like this

#6 Sam M

Sam M

    Ranger 4

  • *****
  • Posts: 387
  • Joined: 05 Jun 2014
  • Loc: Maryland

Posted 02 March 2017 - 02:02 PM

I don't want to detract from what you guys are doing to improve your rigs, but I find my stock Twilight I to be quite serviceable, and I wouldn't want anyone to be scared away from a good value mount.



#7 MarkMittlesteadt

MarkMittlesteadt

    Vanguard

  • *****
  • Posts: 2005
  • Joined: 08 Oct 2013
  • Loc: Rothschild, WI. USA

Posted 02 March 2017 - 02:12 PM

I don't want to detract from what you guys are doing to improve your rigs, but I find my stock Twilight I to be quite serviceable, and I wouldn't want anyone to be scared away from a good value mount.

IMO, the BIG problem with it is the vertical arm, which becomes wickedly unstable when angled back for viewing at zenith. It's relatively stable and damps out quickly with a light scope, low power EP, and the arm oriented straight up. Unmodified, at high power, it is prone to shake when trying to focus. It does damp out in a reasonable time when the arm is straight up. When the arm is angled back, I think the mount is virtually worthless. But that's just my opinion, and probably due to my extreme intolerance for shaky mounts. 

 

It's a valid criticism and one often mentioned. All they would have to do is make a more robust vertical arm to make it a very worthy mount without any additional mods to it. 


Edited by MarkMittlesteadt, 02 March 2017 - 02:13 PM.

  • Jon Isaacs, JHollJr, MrJones and 2 others like this

#8 MrJones

MrJones

    Vanguard

  • *****
  • topic starter
  • Posts: 2431
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 02 March 2017 - 02:21 PM

Not trying to scare anyone - the opposite in fact! My VG3 was very unsatisfying in the state it arrived and I think a lot of people have written off these mounts when they are actually pretty good with some minor attention.

 

My only complaint at this point is that the "night viewing" position with the arm at 45 deg. is not ideal at all with the scope so offset from the center and I find the "day" position with it straight up much better except that I am losing maybe 10 degrees of viewing at the zenith. The "night" position is obviously less bad with smaller and shorter scopes but I will probably at some point drill 2 holes in between existing ones so I can have the arm at a small angle.


Edited by MrJones, 02 March 2017 - 07:50 PM.

  • Sam M likes this

#9 MarkMittlesteadt

MarkMittlesteadt

    Vanguard

  • *****
  • Posts: 2005
  • Joined: 08 Oct 2013
  • Loc: Rothschild, WI. USA

Posted 02 March 2017 - 02:29 PM

Not trying to scare anyone - the opposite in fact! My VG3 was very unsatisfying in the state it arrived and I think a lot of people have written off these mounts when they are actually pretty good with some minor attention.

 

My only complaint at this point is that the "night viewing" position with the arm at 45 deg. is not ideal at all with the scope so offset from the center and I find the "day" position with it straight up much better except that I am losing maybe 10 degrees of viewing at the azimuth. The "night" position is obviously less bad with smaller and shorter scopes but I will probably at some point drill 2 holes in between existing ones so I can have the arm at a small angle.

After I modded mine, I LOVED that mount! The only reason I sold it was because I got into AP and needed a GoTo GEM, or I'd still have it. So yes, the Twilight I (and other identical mounts) are great, lightweight grab'n'go Alt-Az mounts!


  • MrJones and Sam M like this

#10 Sam M

Sam M

    Ranger 4

  • *****
  • Posts: 387
  • Joined: 05 Jun 2014
  • Loc: Maryland

Posted 02 March 2017 - 02:50 PM

 


3) Finally, this is more obvious, tighten the spreader collar. The metal colored one right under the spreader. Then tighten it some more. And maybe again.

 

Better yet, swap the two handles.  It never made sense to me that the tiny hand knob was used to tighten the spreader; while the giant, two bar hand wheel is used to attach the mount head to the tripod.

 

I swapped the two around, and now the giant bar serves its proper purpose.

 

Good point, I'm going to do that as soon as I get home.



#11 stevew

stevew

    Now I've done it

  • -----
  • Posts: 5783
  • Joined: 03 Mar 2006
  • Loc: British Columbia Canada

Posted 03 March 2017 - 10:30 PM

I've also read that taking the rubber tips of the tripod feet helps, but I have not tried it myself.

 

Steve



#12 hardwarezone

hardwarezone

    Messenger

  • -----
  • Posts: 461
  • Joined: 26 Apr 2013
  • Loc: Singapore

Posted 04 March 2017 - 11:41 AM

Epoxy putty into the voids , no winter at my location to worry about different rate of contraction between the aluminum and epoxy.

Drilled and fitted 2 more hex bolts.

Changed to clamp bracket.

 

2l0ilkx.jpg

 

fVtcPtC.jpg

 

bMjhete.jpg


  • MrJones likes this

#13 Jon Isaacs

Jon Isaacs

    ISS

  • *****
  • Posts: 74777
  • Joined: 16 Jun 2004
  • Loc: San Diego and Boulevard, CA

Posted 04 March 2017 - 12:11 PM

 

Not trying to scare anyone - the opposite in fact! My VG3 was very unsatisfying in the state it arrived and I think a lot of people have written off these mounts when they are actually pretty good with some minor attention.

 

My only complaint at this point is that the "night viewing" position with the arm at 45 deg. is not ideal at all with the scope so offset from the center and I find the "day" position with it straight up much better except that I am losing maybe 10 degrees of viewing at the azimuth. The "night" position is obviously less bad with smaller and shorter scopes but I will probably at some point drill 2 holes in between existing ones so I can have the arm at a small angle.

After I modded mine, I LOVED that mount! The only reason I sold it was because I got into AP and needed a GoTo GEM, or I'd still have it. So yes, the Twilight I (and other identical mounts) are great, lightweight grab'n'go Alt-Az mounts!

 

 

I have both the Twilight 1 and the Portamount.  When I first got the Twilight 1, I found it much prone to vibration than the Portamount.  My portamount has a set of wooden legs,  that helps.. 

 

I really wanted to understand the reasons why the TW1 was so prone to vibration.  I spent three nights on this project.  What made this doable was the fact that the TW1 and  the Portamount use interchangeable gear boxes so I could swap parts between them.  For these comparisons,  I used my 4 inch F/5.4 Televue.  12.0 pounds ready to go,  about 29 inches long.  Not ideal but workable on the Portamount,  unusable on the TW1.

 

What I found was what Mark found,  the arm is the weak point,  it's just too flexible.   I made an arm from 3/4 inch oak,  it helped a little,  I think something like the arm Mark made or a stiff aluminum arm would do the job. 

 

This mount is rated for 15 lbs.  No way.. 

 

Myself,  I share my experiences.  An 80-102 mm refractor requires a mount that is stable at close to 300x.  For an 80 mm,  the TW1 is passable but not ideal.  For a 4 inch stock,  and that is with everything tight,  it's not acceptable.  The portamount is close to ideal with an 80 mm,  passable but not ideal with a 102 mm.. 

 

I am not afraid of scaring people away from the TW1, I am afraid of the buying it for a larger scope and finding it unacceptable.. 

 

Jon


  • MarkMittlesteadt likes this

#14 jeremiah2229

jeremiah2229

    Apollo

  • *****
  • Posts: 1360
  • Joined: 25 Jul 2015
  • Loc: Illinois, USA N 37° W 89°

Posted 05 March 2017 - 12:29 AM


bMjhete.jpg

What saddle are you using here?

 

Thanks...



#15 Sam M

Sam M

    Ranger 4

  • *****
  • Posts: 387
  • Joined: 05 Jun 2014
  • Loc: Maryland

Posted 05 March 2017 - 12:37 AM

Jon, I think we can all benefit from the research that you've done.  And it makes sense not to buy the TW1 if you want to spend time at 300x with a 29 inch, 12 lb refractor. 

 

I don't have any problems with my C6 and binoviewer at 300x. ES says the AR102 is 10.4 lbs. give or take for eyepieces and because (like you) I usually only use a red dot finder. I've never found it unacceptable on the stock TW1. Although, it's rare that I have that scope up to 300x. 

 

Of course people have different tastes as far as how stable and portable their mounts should be. Hopefully we've helped clarify what people can expect for $200. And yes, I'm definitely interested in hearing how people improve on that. 



#16 hardwarezone

hardwarezone

    Messenger

  • -----
  • Posts: 461
  • Joined: 26 Apr 2013
  • Loc: Singapore

Posted 05 March 2017 - 03:00 AM

 


 

What saddle are you using here?

 

Thanks...

 

 

 

www.ebay.com/itm/Large-Universal-Vixen-Mounting-Platform-dual-Clamp-aluminium-with-brass-clamps-/201514688611?hash=item2eeb362063:g:~esAAOSwnLdWrYBo

www.ebay.com/itm/292038885743?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

I bought mine direct from China instead of ebay reseller though , less than half price.

 

Due to the new CNC clamp bracket being slightly less in thickness , a pair of 1/4-20 x 1/2" length bolts are needed to mount.

The clamp and dovetail surface are too slippery and I added a bolt on the dovetail as safety.


Edited by hardwarezone, 05 March 2017 - 03:10 AM.

  • jeremiah2229 and Cali like this

#17 Redbetter

Redbetter

    Fly Me to the Moon

  • *****
  • Posts: 6996
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 05 March 2017 - 04:18 AM

It has been a while since configured this mount, but I noticed a number of the same issues.  It does pretty well with an 80ED at 150x but is taxed with the 110ED.  Vibration is far slower to dampen than I anticipated with either scope.

 

I believe there was also some mention in another thread of rotating the azimuth attachment by disassembling the base plate and using a different set of bolt holes.  I did this but don't recall the details. 

 

I agree that the arm is part of the problem.  It is more stable in the vertical position, but of course that is non-ideal.  I wish the other position was 45 degrees or so rather than 30 degrees.  This would reduce the length of the lever arm (that seems to act like a spring when reclining) while still permitting clearance from what I measured.  I haven't tried to stiffen it yet.  The design of the arm probably would have been better served by having ribbed cross braces to keep weight down and rigidity up.

 

 

I was using it tonight splitting doubles at about 200x in the 80ED with the arm vertical and that was okay.  But I recall having more trouble when it was reclined when I first got it.  I'll give it another try with arm back again.



#18 MrJones

MrJones

    Vanguard

  • *****
  • topic starter
  • Posts: 2431
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 05 March 2017 - 09:28 AM

I had 27 lbs of 6" goodness on mine last night.

 

 

Attached Thumbnails

  • starwave152.jpg

  • Sam M likes this

#19 Sam M

Sam M

    Ranger 4

  • *****
  • Posts: 387
  • Joined: 05 Jun 2014
  • Loc: Maryland

Posted 05 March 2017 - 05:05 PM

Wow!  So that's just a wood block, huh.  Did you cut it any special way?  Hardwood?  



#20 MarkMittlesteadt

MarkMittlesteadt

    Vanguard

  • *****
  • Posts: 2005
  • Joined: 08 Oct 2013
  • Loc: Rothschild, WI. USA

Posted 05 March 2017 - 05:46 PM

Wow!  So that's just a wood block, huh.  Did you cut it any special way?  Hardwood?  

On this?

 

mounthead-done.jpg

 

If you meant mine, it's a two piece maple board, glued together after I cut the offset out of one (to accommodate the circular metal part of the stock attachment point...you can see the notch cut out in the pic at the lower left of the block). I also had to notch out the wood where the tiny (and useless) perpendicular metal brace sticks out. At the top of the maple block I cut out a circle to fit the PVC extender. 

 

The maple upright block and PVC got screwed to the stock arm from the outside as well as two screws underneath (I removed the magnets in the stock arm). The PVC extension (to mount the altitude assembly outward laterally) has two circular maple blocks screwed into each end. One end gets screwed to the stock vertical arm, the other gets the altitude assembly attached. There is one long lag screw running through the middle of the PVC, straight down into the upright maple block. 

 

arm-mod2.jpg

 

It's about a $10 and 2 hour mod that makes it extremely rigid, even at higher powers. 


Edited by MarkMittlesteadt, 05 March 2017 - 05:49 PM.

  • Cali likes this

#21 MrJones

MrJones

    Vanguard

  • *****
  • topic starter
  • Posts: 2431
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 05 March 2017 - 06:23 PM

The woodblock I used for vibration damping is scrap pressure treated wood if you're asking me. I will be adding another piece to the other gap and making it look better soon. I do like Mike and others' bolt on plates as the best solution but the wood block does really well.

 

So in the end it took 1 minute of drilling 1/4" holes and 2 1/4x1" bolts + washers to get this thing to do 60 deg. instead of 90 deg or 30 deg. It's annoying to have to make this obvious change but pretty easy.

 

I also added 1" felt furniture pads to go between the legs and spreader. The fit between the round leg and V angled spreader ends always seems dicey. Can't hurt right?

Attached Thumbnails

  • newvg3.jpg

  • redbaron12 likes this

#22 Redbetter

Redbetter

    Fly Me to the Moon

  • *****
  • Posts: 6996
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 05 March 2017 - 06:48 PM

It looks like you also drilled extra holes to allow a steeper angle for the arm.



#23 Sam M

Sam M

    Ranger 4

  • *****
  • Posts: 387
  • Joined: 05 Jun 2014
  • Loc: Maryland

Posted 05 March 2017 - 07:44 PM

I was referring to Mr Jone's wood block.  Sorry for not quoting.  Mark, what you've done there is really impressive, but what for you is a 2 hour mod, for me would be, "I broke my mount."  I'm much more of a stick-a-piece-of-wood-in-there kind of guy.  It's pretty amazing that Mr Jones was able to use a 27lb long scope like that, so I was wondering if the woodblock was a tight fit, and if so how he got it tight.


  • MarkMittlesteadt likes this

#24 MrJones

MrJones

    Vanguard

  • *****
  • topic starter
  • Posts: 2431
  • Joined: 15 Sep 2010
  • Loc: Indiana

Posted 06 March 2017 - 09:19 AM

"It looks like you also drilled extra holes to allow a steeper angle for the arm."

 

Yes! It's in the post above the photo.

 

"It's pretty amazing that Mr Jones was able to use a 27lb long scope like that, so I was wondering if the woodblock was a tight fit, and if so how he got it tight."

 

I trimmed a piece of scrap with a circular saw until it almost fit then (lightly) tapped it in with a hammer.

 

The 27lbs of 6" achro on the mount was an eye opener. First of all the mount has no problem at all holding this much weight and operated smoothly so it's going to be about performance. Low power views (~25x)  seemed even more stable, I'm guessing due to the extra weight on the mount. At 90x though the settling time was turning into seconds so that's probably going to be the limit. I will certainly be taking that scope out more now that I can put it on the VersaGo III. As per some post's above including Jon Isaac's though, if you really want 300x with your 4" triplet on a manual alt-az, you're going to have to spend more money. A lot of people got these Twilight 1 and related mounts for $150 or so though, and I like mine just fine after the mods for what I'm going to be using it for.


  • Sam M likes this

#25 Redbetter

Redbetter

    Fly Me to the Moon

  • *****
  • Posts: 6996
  • Joined: 16 Feb 2016
  • Loc: Central Valley, CA

Posted 07 March 2017 - 05:18 AM

I tried the reclined arm position out again tonight with the 80ED on Jupiter and double stars at 150 to 200x.  The difference between this and the vertical position is noticeable.  While it is very manageable with this light, fairly short tube and these powers the damping time is seconds, and it is in both axes.  To me his indicates the problem is with the spring like lever arm that is created and extends nearly equally into the vertical and horizontal.  I think having the arm at 60 degrees rather than 30 would help a lot, although for this tube it is not that large of a problem.    It is possible that 60 wouldn't quite clear in the vertical for some scopes/orientations particularly with the tripod leg connections to the mount head.

 

Perhaps a better design would incorporate a stiffer arm along with horizontal slide for the altitude position--either that or multiple hole positions on a bracket that could be moved further back as needed.  A triangular section to the arm extending toward the rearmost position could help stiffen it without interfering with focuser positions etc. at the back of a tube.  Additionally the arm thickness could be somewhat wider.  Might add one to two pounds in all.   




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics