hickeydp
professor emeritus
Reged: 06/14/09
Loc: Ireland
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How far have you pushed your G11?
#5551882 - 12/03/12 11:33 AM
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I know this comes up a lot and generates a lot of debate about how far you can push a G11 weight wise. I'm aware the stated load limit is 60lbs with a max of 40lbs counterweight. I have also read where certain people maintain this is a conservative load limit.
My question is to those of you who have thrown out the rule book and have thrown a lot of weight at your G11's. I'm looking for empirical experience. How far have you pushed it and how did the motors cope with it?
The reason I ask is that I have almost finished building a 16" f5 newt that will weigh in at nearer 70lbs and I'm quite worried about putting this on my G11 and burning out the motors (not to mention the problems caused by the tube length).
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D_talley
Carpal Tunnel
   
Reged: 07/07/05
Loc: Richmond VA
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Re: How far have you pushed your G11?
[Re: hickeydp]
#5552042 - 12/03/12 01:20 PM
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The biggest problem you will face is the tube length. As you can see in my avatar I have a 65 lbs Meade 14 OTA and three 22 lbs counter weights on my G11. I was using the standard motors but upgraded the motors later. I was able to image with Hyperstar with this setup. I now have a Meade 12 and a TEC 140 on the mount at one time. No problems with the motors.
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rsbfoto
sage
Reged: 06/10/06
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Re: How far have you pushed your G11?
[Re: D_talley]
#5552080 - 12/03/12 01:45 PM
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Hi Damien,
I have 2 G11 and both are equipped with 66pounds equipment and 66 pounds counterwights since 4 years and motors work fine.
The main question here is the balancing of the mount, because then the only thing the motors do is move slowly the whole equipment and not much force is needed.
As Dwight said one problem can be the length of the scope.
I would say that in order to know it, mount your scope on the G11 and make some carefull tests and you will see what happens and if you feel confident leave it. If you do not feel confident then you will need another mount.
Edited by rsbfoto (12/03/12 01:47 PM)
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Hilmi
Carpal Tunnel
   
Reged: 03/07/10
Loc: Muscat, Sultanate of Oman
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Re: How far have you pushed your G11?
[Re: rsbfoto]
#5552091 - 12/03/12 01:50 PM
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Losmandy has recently introduced some newer model higher torque motors, these should help with heavier loads.
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mega256
scholastic sledgehammer
   
Reged: 05/10/07
Loc: N of Tampa
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Re: How far have you pushed your G11?
[Re: Hilmi]
#5552116 - 12/03/12 02:05 PM
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I have a G11 and C14..... 2 Things make it work well...
#1.....14" Robin Casady dovetail Saddles
http://www.robincasady.com/Astro/dovetail.html
#2..... The new HD motors by losmandy...very good! at least on the dec..(super tourge)
This setup works well..... I use 44 lbs of counter weight with no problems..The old standard motor would just get warm when slewing,but the new one stays cold to the touch...($225).. So just try it and then do some of these changes for improvments....
If you load the 16" light,,,no heavy extras,slow down the slew rates....should work...but much over the 70 lbs....maybe..?
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dobsoscope
sage
   
Reged: 05/24/06
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Re: How far have you pushed your G11?
[Re: mega256]
#5552353 - 12/03/12 04:19 PM
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What if it is permanently mounted on the G11 would you still need the Casady dovetail.. probably not!
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mega256
scholastic sledgehammer
   
Reged: 05/10/07
Loc: N of Tampa
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Re: How far have you pushed your G11?
[Re: dobsoscope]
#5552531 - 12/03/12 06:15 PM
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Mine is on a cement 12" pier,I say yes....But the
tripod is very strong....I would keep it low,and out of the wind..FOR sure....
I had a 12" F4 AT12IN and it worked ok....
But because of such a long tube you need a long base to
keep flexture down..
I think any scope over a C11 would benifit from a longer
saddle.
New motors
http://gemini-2.com/Losmandy-motors.php
Edited by mega256 (12/03/12 06:27 PM)
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hickeydp
professor emeritus
Reged: 06/14/09
Loc: Ireland
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Re: How far have you pushed your G11?
[Re: mega256]
#5552689 - 12/03/12 07:45 PM
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Thanks for the input guys. I have my G11 permenently pier mounted and it's very solid. From what I'm hearing 70lbs will be at the outside edge of what it can do. I should say that the weight I'm quoting is fully loaded with camera and guide scope. For visual it would be almost 8lbs lighter.
It did cross my mind that a longer saddle would help a lot. I will also look into one of those bars that connects the tube to the counterweight bar. Can't remember what they are called.
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Startraffic
sage
   
Reged: 02/12/06
Loc: Lat. 39.143345, Long. -77.1748...
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Re: How far have you pushed your G11?
[Re: hickeydp]
#5553547 - 12/04/12 08:38 AM
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hickeydp, I've hung a Meade 10"f4 SNT, Celestron C6R 152mm f8, & an Ioptron 90mm f4 as a guidescope, & a 30mm finderscope on a HD tripod for an outreach event. It was a clear, dead calm day, but not in a dome doing solar observing. WELL balanced in all axis is an absolute MUST, but it did work, once. It gave me the ability so show the difference between the 2 scopes. Since then I've only hung the SNT, 90mm & finder scope on a regular basis, no big deal. I'll probably do the same thing again this year using my HGM-200 for the same setup.
Clear Dark Skies Startraffic 39.138274 -77.168898
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hickeydp
professor emeritus
Reged: 06/14/09
Loc: Ireland
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Re: How far have you pushed your G11?
[Re: Startraffic]
#5553765 - 12/04/12 11:10 AM
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Wow, I'd say balancing all that was fun/challenging. I'm getting the impression that this old workhorse can really carry weight if balanced properly. Hoping to have my newt done by Christmas so I can use it over the holidays.
Here's the build thread for those interested...
http://www.cloudynights.com/ubbthreads/showflat.php?Cat=0&Board=atm&N...
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Startraffic
sage
   
Reged: 02/12/06
Loc: Lat. 39.143345, Long. -77.1748...
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Re: How far have you pushed your G11?
[Re: hickeydp]
#5558753 - 12/07/12 07:32 AM
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hickydp, Yup & it just keeps coming back for more. I like that. Clear Dark Skies Startraffic 39.138274 -77.168898
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Dan McConaughy
sage
Reged: 11/11/06
Loc: LA
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Re: How far have you pushed your G11?
[Re: Startraffic]
#5562190 - 12/09/12 10:54 AM
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Running the slews more slowly makes things work better. I run a 16" with the Gemini system using Maxxon motors on a larger mount at 400X and have not had a problem with the slewing. It actually works a bit better when it is slightly out of balance against the slew. I run it at 18 volts and that helps, too.
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Danno2006
Pooh-Bah
Reged: 01/25/06
Loc: Ontario, Canada
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Re: How far have you pushed your G11?
[Re: Dan McConaughy]
#5562678 - 12/09/12 03:45 PM Attachment (16 downloads)
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C14 with top mounted 80mm Raptor. It needs 3 x 21 lb. weights almost to the end of the counterweight shaft. It has the Maxon motors which helps vs. the regular motors.
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hickeydp
professor emeritus
Reged: 06/14/09
Loc: Ireland
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Re: How far have you pushed your G11?
[Re: Danno2006]
#5563810 - 12/10/12 09:27 AM
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Cheers again for the info guys. I'll report back when I have my 16" up and running. I've taken a break from it for a few weeks as work has me flat out and I'm trying to have a social life too
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Hilmi
Carpal Tunnel
   
Reged: 03/07/10
Loc: Muscat, Sultanate of Oman
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Re: How far have you pushed your G11?
[Re: hickeydp]
#5563912 - 12/10/12 10:42 AM
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Social life? I hope you don't mingle with the disreputable sorts who go out during the day time!
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Eric P
sage
   
Reged: 04/04/05
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Re: How far have you pushed your G11?
[Re: hickeydp]
#5564071 - 12/10/12 12:22 PM
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I built a split tube OTA for a 6" achro but given the weight and length it was completely under-mounted on the G11. Way too jittery to make it useable.
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