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On 11/18/2023 3:03 PM, Michael A. Covington via groups.io wrote:

We should add that -- unless somebody knows something I don't --
Losmandy mounts don't require perfect balance unless they are very heavily loaded.

That depends on what you are using to determine whether imperfect balance is affecting you.? It also depends on how much DEC backlash you have.? With 3rd axis balancing and a couple mods to the worm assembly, my DEC backlash is a thing of the past.? It used to be 2500mS on a GOOD day and highly variable.

YMMV.... but mine didn't ;)

Paul

--
Paul Goelz
Rochester Hills, MI USA
pgoelz@...
www.pgoelz.com

We should add that -- unless somebody knows something I don't --
Losmandy mounts don't require perfect balance unless they are very heavily loaded.

Over in the iOptron user community there is or was constant kerfuffle about balance.? The reason?? iOptron mounts swing *very* freely when unlocked, so even a few grams of imbalance can be noticed.

On the other hand, AVX owners don't complain about balance because AVXs are so stiff that they don't move when unlocked unless the imbalance is quite large.? The hard part about balancing an AVX is detecting the error!

I have this same issue on a new scope I just got, a little 75mm petzval.? The focus motor seems to be hung out enough that it affects the '3D' balance.? I was thinking of making a block to screw to my Losmandy style plate with a threaded rod and some weights, similar to what Paul describes.?

Brian

On 11/18/2023 11:02 AM, peter@... wrote:

When I balance a scope, I get conflicting results depending on where the axis' are when balancing. It seems it should be balanced providing a stable position no matter how I turn the scope. Like a neutral condition. But if I balance it when the scope is level, and then move the axis so it is not level, it is not balanced anymore.

Chances are you have some mass that is not fully concentric with the centerline of the scope.? Like a focuser motor or a filter wheel sticking out to the side.? This will require that you add a corresponding mass to the other side of the scope (referred to as balancing the third axis).? This can be done by attaching a weight directly to the side of the scope or (more commonly) on a stalk attached to the RA shaft, perpendicular to the scope optical axis.

With the RA shaft horizontal, loosen the DEC clutch and carefully balance the scope with the tube horizontal.? Now swing it to vertical (ie, pointing straight up or down).? If it does not remain stationary when you release it, you need to balance that third axis.

There are surprisingly few commercial solutions out there so I made mine by 3D printing a collar for the RA shaft with a threaded hole for a grub screw to hold it tightly in place.? I screw a piece of threaded rod into that grub screw hole to lock the collar in place and the threaded rod carries a stack of large fender washers (my poor man's counterweight) that can be adjusted in and out between a couple nuts for a perfect balance.

Paul

--
Paul Goelz
Rochester Hills, MI USA
pgoelz@...
www.pgoelz.com

On Sat, Nov 18, 2023 at 12:30 PM, @VictoryPete wrote:

I can find no warranty information anywhere.

Pete, please contact Losmandy directly for things like this.

I can find no warranty information anywhere.

When I balance a scope, I get conflicting results depending on where the axis' are when balancing. It seems it should be balanced providing a stable position no matter how I turn the scope. Like a neutral condition. But if I balance it when the scope is level, and then move the axis so it is not level, it is not balanced anymore.?

I have decided that once an initial adjustment has been made using both screws, I will make occasionally needed tweaks by just adjusting the spring screw. It is very intuitive that way.

I have a 120mm refractor on a G11G that works superbly. It's mounted on a pier in my backyard observatory, but even if I had to carry it out to set up, I'duse the same mount - the RA extension means the mount breaks into RA and DEC, basically halving the weight of what I would have to manhandle.

You asked why a GEM is my preference for visual??? Several reasons:

1. tracking
   1. for times when I step away for a moment, or an hour, the target stays in the eyepiece
   2. for sharing the view with family and friends - keeping the target in the eyepiece isn't something I have to worry about or instruct others how to do
   3. because I almost always have two scopes going at once, one for AP and the other for visual, so I'm always going back and forth between the two
   4. at high power (planets, the moon) this factor becomes immensely important
2. The movement of EQ mounts just makes sense to me, because they move the way the heavens do.? Not that Alt-Az doesn't make sense, but for astronomy I have been using EQ mounts since I was a kid, so it just feels right.??
3. astrophotography is always an option

My very first scope was a refractor on an alt-az mount - that grew old pretty quickly.? The moon and planets just whizzed by, and I didn't enjoy tracking by hand.? I know there are plenty of people quite skilled at that, especially with dobs, but it's just not my thing.? There are some awesome quality alt-az mounts that probably hand track quite smoothly, but to me nothing beats the mount doing the work for me!

~~Aaron

I have two G11Gs running Gemini II.? #1 I use ASIair, which plate solves and does its thing, no model involved.? However, when I DID use it for observing, the mount was accurate with a decent PA and 2 or 3 stars in the model - but if I put in more stars the mount became more accurate.? The most stars I ever used was, if I recall, a couple dozen.? But I don't know if you'd notice a difference after 5 or 6.?

Same with mount #2 - it's my visual mount now.? I have 5 or 6 stars in it, and it's extremely accurate on the East side, less so on the West side, which means I need to add more stars on that side of the model.? But even on that side my target is within the finderscope, usually within a low power eyepiece.? In my experience, the more alignment stars you give it, the more accurate it is.

According to my understanding of how the mount and Gemini (or any goto mounts) work, it makes sense.
--
~~Aaron

IME only really need to get a couple of alignment points on both sides of the meridian to have better GOTOs on both sides of the meridian. Also be sure to turn off any auto sync and alignment options after plate solving if you will be doing a lot of GOTOs.with plate solving. The model table can get confusing data that ruins GOTOs that otherwise would have been fine with just the basic 2-4 alignment points on both sides of the meridian to use in the model.

--

Chip Louie Chief Daydreamer Imagination Hardware?

? ?Astrospheric Weather Forecast - South Pasadena, CA?

I had an RA Stall message on the hand controller, but it wasn't displayed on my laptop in the Gemini App. How would I have known if I was not using the hand controller? I simply loosened the spring screw, and it is now fine. Compared to the complicated adjustment shown in the Losmandy videos, is this a simple way to adjust the spring loaded worm gear?

I have actually? never built a model.? I'm 100% imaging in the 3 month's I've had my G11G.? I have a permanent pier now, and got polar aligned to 30 arc seconds.? I start with CWD set by eye with the levels on the RA and DEC.? My go-to my first target in the Eastern sky is usually only a few arc-min off.? I can tell this by the display on the ASI Air.? It shows the coordiantes of the target, and the plate solved coordinates.? So that seems pretty good to me.? I will then do a sync and center to get spot on.

When it flips to the West, it can be WAY off - like 10+ degrees.? I don't really know if this is an ASI AIr thing, or a gemini thing, as perhaps the gemini having only one sync point on the East and no points on the West doesn't know what to do with itself.? But a plate solve and recent works just fine.??

I add this commentary because I believe the mechanical accuracy is there in these mounts - as evidenced by a very close go-to of the first target from a very accurate polar alignment.? ? I need to explore the software? more.
?
Brian

G11T owner here.? I stopped building models about a year ago as I'm wholly astrophotography on this kit (LX200 10" and ED127 tandem, pier mounted).

When I was building models, I would align 3 stars on East and West sides, always using the LX200 as my alignment scope (as the ED127 is mounted on a TGAD which allows for final alignment of the two telescopes) and the LX200 presents a smaller FOV, thereby a more accurate pointing alignment.? Polar alignment is done with PoleMaster.? Results after model building were "placement" consistent, but not always dead on accurate, meaning sometimes I had to search around a bit to find the alignment star, but not excessively so. If I modeled properly, it worked.? And if it was a bit off, I'd align again when this occurred.

My take on models is that they work but are somewhat subjective relative to model build process and user expectations. How that jives with Losmandy's description again I believe its subjective. Nonetheless it states, "to deliver excellent pointing accuracy across the entire sky using multi-star alignment models".? Consistency in the process of building "multi-star" models is important. If one has built a "bad" model, then the results are not going to be accurate (I've done this many times BTW).? Conversely, if one builds a "good" model and the accuracy is a bit off, e.g. in the eyepiece but not centered, does that constitute accuracy failure?? From my perspective I would say no, I'm good to go with that.? Others may declare its not accurate as it's not exactly centered in the eyepiece.? It's pretty subjective at that point too.

As Paul asked, defining how you build a model would help members here help you.

- Jerry

Clayton,

As a previous owner of a G11T, I can tell you that Gemini 2 and the Losmandy mount is very accurate,? repeatable, and reliable.

Not sure what scope you use, I have used a 2600mm fl Maksutov to a 550mm fl refractor.?? I have done visual through the scope to line Polaris up and used Sharpcap.? Sharpcap was on the refractor.?

That being said, the first modeling star, I do modeling, is always off but generally in the FOV of a low power eyepiece, Maksutov scope being used here. After centering and aligning, that second star is closer, the third closer yet.? I typically do 5 - 6 stars per side, east and west.? When I use Sharpcap for polar aligning the first star is off,? but always in the FOV of my 533 chip camera. Again, after aligning 5 or 6 stars everything is pretty much in the center.

I use Sharpcap with the refractor, don't have a big chip camera to allow use for the Mak.?? I do have the luxury of using Sky X T Point for PA, using it the mount is always dead on with either scope.

It seems to me that Gemini builds two models, one east and one west.? Now my ground is marked, I have plates on the concrete to put the legs of my portable pier in, so I am in the same location every night.? If you can, I'd recommend marking the ground where you set up.

The mount is very accurate, model a bunch of stars east and west or plate solve.

My experiences,?? Joe

Paul,

I apologize, I did not read all of the post in entirety.? As for a C14 on a G11T, my G11T threw my C14 around like nothing, and that was with a Homemeyer Cradle too.? I did have the Losmandy power supply too.

I say no more.??? Joe

On Fri, Nov 10, 2023 at 08:34 PM, joe kuhl wrote:

That's what I thought the OP was talking about.? Random stalls.? To be honest, this seems to be a long conversation to solve that kind of problem.

I'm not sure what you're reading, Joe, but there are multiple conversations going on here, with different topics. The topic of stalls has been covered at least a few hundred times here and elsewhere. Nearly all stalls are the result of incorrectly adjusted balance, worm, bad lube, other incorrect adjustments, and sometimes, malfunctioning servos. The OP has some significant weight on the mount, so all adjustments are doubly important. The rebooting of Gemini controller during a stall is almost certainly caused by an insufficient power supply that can't deliver current and maintain voltage under load. All of this has been covered.

If you have other ideas or suggestions, you're welcome to share them. Complaining about why it's taking so long to resolve someone else's problem isn't helpful.

Regards,

? ? -Paul

Paul,

That's what I thought the OP was talking about.? Random stalls.? To be honest, this seems to be a long conversation to solve that kind of problem.

Just me, again, I don't have a dog in the fight.

Joe