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I sold my G11G w/ LW Tripod to Francisco.? Please welcome him and help him out when he has questions.

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Jim W
Phoenix, AZ. USA

Losmandy G11G w/ L6, NINA 3.0 / ASTAP, ASI2600MC Pro, Sky-Watcher Scopes, Canon L Lenses.

On Thu, Feb 13, 2025 at 06:55 PM, <avishekaiyar@...> wrote:

I am going to try a few imaging sessions to see if there is a real problem.?

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Then my next step would be a regressing if needed.?

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Thanks for the tip on the high friction clutch pads. Will surely keep that in mind.?

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Many thanks.

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Avi?

?Avi,

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It really is dependent on having a well balanced payload in the saddle.? Check out this guy's method of balancing.? This is basically what I have been doing for every mount and scope I have owned for the last 50 years.??

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Hope this helps.?

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I am going to try a few imaging sessions to see if there is a real problem.?

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Then my next step would be a regressing if needed.?

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Thanks for the tip on the high friction clutch pads. Will surely keep that in mind.?

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Many thanks.

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Avi?

On Tue, Feb 11, 2025 at 07:08 PM, joe kuhl wrote:

Hello Francisco,

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Image scale is what you need to track under.? Your periodic error has to be less than your image scale you are shooting at.? With a 2600 camera that has 3.76 micron pixels, you need to guide under .4, that is a 12 LX200 OTA with a .63 reducer.? With a 2400 camera you are at .64, more manageable but still kind of tough to do.? My opinion.? Reason,? you have a 14" barrel that is over 24" long with a dew shield on top of that mount. A 6" RA and Dec gears driving it. ?

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Joe

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I don't understand how you came up with this.? Regardless of optical resolution or camera seconds per pixel image scale or how well the mount tracks the rate limiting factor when imaging from the surface of the Earth is the quality of the air column between the sensor and the object.??

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On Wed, Feb 12, 2025 at 09:28 PM, Ron wrote:

Avi

A Long long time ago I had the same problem. I’m using 53 pounds of counterweight and with my attached 80 mm piggyback to my 10 inch RC at certain positions in the sky I would get slippage with the stock nylon Losmandy clutches even though I hand tightened the knobs as tight as I could . Michael Herman’s disc clutch was a game changer for me. I am an imager and keep the knobs tight, I platesolve then move the mount through gemini.net - not into the visual push to technique?

most likely this will solve your problem and then you will have more fun

Ron

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The amount of counterweight should not make a difference.? The most counterweight I have used was:? 3x21 + 1x11 + 1x7 = 81 pounds total CW.? But even my typical 70 pounds of CW shows no slippage while imaging. The clutches are firm to be sure but still only hand tight.? Just don't bump anything and you'll be fine.?

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Avi

A Long long time ago I had the same problem. I’m using 53 pounds of counterweight and with my attached 80 mm piggyback to my 10 inch RC at certain positions in the sky I would get slippage with the stock nylon Losmandy clutches even though I hand tightened the knobs as tight as I could . Michael Herman’s disc clutch was a game changer for me. I am an imager and keep the knobs tight, I platesolve then move the mount through gemini.net - not into the visual push to technique?

most likely this will solve your problem and then you will have more fun

Ron

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As designed the Losmandy mounts work well if the mount is in good mechanical condition with clean dry clutch discs and a well balanced payload.? It's pretty simple, if you need to crank down on the clutches to avoid slippage there is something wrong with your mount or how it is being used.? ? ??

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Joe

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Same question as Chip.? Walk us through the math.? Yes, an AP mount or above would be better.

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Jim W
Phoenix, AZ. USA

Losmandy G11G w/ L6, NINA 3.0 / ASTAP, ASI2600MC Pro, Sky-Watcher Scopes, Canon L Lenses.

On Tue, Feb 11, 2025 at 07:08 PM, joe kuhl wrote:

Hello Francisco,

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<<SNIPPED>>

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Image scale is what you need to track under.? Your periodic error has to be less than your image scale you are shooting at.? With a 2600 camera that has 3.76 micron pixels, you need to guide under .4, that is a 12 LX200 OTA with a .63 reducer.? With a 2400 camera you are at .64, more manageable but still kind of tough to do.? My opinion.? Reason,? you have a 14" barrel that is over 24" long with a dew shield on top of that mount. A 6" RA and Dec gears driving it. ?

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<<SNIPPED>>

Joe

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I'd like to hear how you calculated these numbers.? What is the method and why?? ? ?

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Yeah Joe, a set screw.??

As you say, there are bigger mounts to be had and at bigger price points.

Tracking/Guiding is a discussion all of its own!.

If DSO at native FL were the primary purpose I might think differently, but IMO there's a long way to go before the mount would become the limiting factor.

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Michael?

What is a grub screw??? Is it like a set screw??

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Joe

At one time I used Blue Loctite on the grub screws and quickly regretted it.? It wicked onto the shafts.? It took me an entire weekend to clean stuff up.?

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Several years ago I replaced the grub screws on the two aluminum 1-to-1 transfer gears with 4-40 x 1/4 cap screws. Theses work much better than the original grub screws but occasionally they work loose too.?

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Jim W
Phoenix, AZ. USA

Losmandy G11G w/ L6, NINA 3.0 / ASTAP, ASI2600MC Pro, Sky-Watcher Scopes, Canon L Lenses.

Are you all good to go again?

On Mon, Feb 10, 2025 at 12:48 PM, Jim Waters wrote:

Francisco

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With any luck it will be clear enough tonight to do a PHD2 guiding run.? I adjusted the RA worm to ring gear spacing and I want to make sure I didn't mess things up.? I also found some loose grub screws.? I will contact you Tuesday PM.

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Jim W
Phoenix, AZ. USA

Losmandy G11G w/ L6, NINA 3.0 / ASTAP, ASI2600MC Pro, Sky-Watcher Scopes, Canon L Lenses.

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Use a drop of low torque thread adhesive on those darned Oldham grub screws.? Loose grub screws are one of the most common issues and cause a lot of grief to the uninitialized.? If you are having issues with your drivetrain those grub screws are right up there with worm axis endplay.? ? ?

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Hello Francisco,

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Do not get me wrong, I firmly believe at the under $5000 budget Losmandy makes the best mounts in their class.? I owned a G11T for a year.? I thought I wanted two rigs,? it was for my C14.? It moved the C14 around, I used it for visual and it was very good.? However, I also owned two refractors at the time, that C14 was noticeably heavier to push across the grass. I donated the C14 to my local middle school for their astronomy program, the mount went to my neighbor.?

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As Michael above pointed out,? there are a lot of things that affect pointing and tracking when doing DSO imaging.? I know you said you are just trying it out and not really going to do it. That is great.?

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Image scale is what you need to track under.? Your periodic error has to be less than your image scale you are shooting at.? With a 2600 camera that has 3.76 micron pixels, you need to guide under .4, that is a 12 LX200 OTA with a .63 reducer.? With a 2400 camera you are at .64, more manageable but still kind of tough to do.? My opinion.? Reason,? you have a 14" barrel that is over 24" long with a dew shield on top of that mount. A 6" RA and Dec gears driving it. ?

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My opinion, ? a mount with a 10" RA gear and 8" minimum Dec gear.? If you get serious about DSO imaging with a 12" SCT.? If it were me, and I know this is a Losmandy group, but with a 12"SCT for DSO imaging successfully an AP1600GTO, 10 Micron 2000GPS,? a Planewave or ASA mount .

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At 50 pounds you are approaching the weight limit,? physical size you are probably over the limit, focal length you are past the limit.? The least little thing and you are done. No room for error. A gentle breeze of wind, someone walking around.

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Planetary, visual yes. EAA yes.? DSO, I'm going with no.? Final answer.

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Joe

Hi- I was told that it would be OK to let the group know I have a G11 mount/tripod for sale.? But rather than overextend my site privileges, I'll leave it to you to contact me privately or see the ad on Astromart for details.? Thanks.? J.R., Gainesville, GA

I believe it was the battery

Hi Francisco,

Welcome to the group.?

Weight limits are SO problematic. To start it's barely a relevant measure, but marketing people had to find something simple they could use in their ads to out spec their competition. Now we're all stuck with it. ?

Hence the sarcastic commentary of "is that in 'Chinese' pounds",? or? "the rule of thumb is divide by 3 for AP" (easy to remember) or "is X makers rating real?" and now it's "it's X for visual and Y for AP" ,

(which ignores the question is that short exposure planetary or long exposure DSO AP? )

You get my drift. ???

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Moment of inertia is the actual factor thst matters (Mass x distance from the axis of rotation). Its a bit messy to put that in an ad, much less explain it, AND it's only one factor in "suitability for a purpose" which is the? right question to ask.

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Kudos to the seller BTW who obviously has super high integrity. ???

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I won't get into it here, other then to say there is a big difference between a long f/10 refractor and a f/10 SCT? that might be of equal weight when it comes to "can this mount handle it"?

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You'll fnd it discussed if you search or browse in the forum archives which i highly recommend anyway. It's a resource of all things about Losmandy. many of which you (and I) haven't yet thought to ask. ?

I jest a bit in fun, but it really, is a bit overwhelming in the best possible way.?

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Long exposure AP at 3k mm FL is super challenging for reasons too numerous to mention. I've learned here that? the fundamental challenge is how to methodically isolate the cause of an observed issue and then how to go about fixing or reducing it. It takes experience.?

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That's what I have come to appreciate about this group after I bought my used? older G11 mount.

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There are many VERY experienced people and SMEs in this and related Losmandy/Gemini groups that are very generous and willing to share their knowledge and experience, which IMO is way more important than any of the multitude of factors that will impact achieving your desired results at one point or another.

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FWIW, Losmandy makes an adapter for Meade tripods. A lot of? mounts are sold with this adapter and a Mead tripod before Losmandy started making their own tripod. I bought my used G11 in that configuration. The more modern Meade giant field tripod (LX200GPS) are ok for visual/planetary What was better was an older Giant FT from the LX200 classic. 3"+ dia legs and taller (if you are a really tall person or have a long refractor.) I bought a used Losmandy original non folding HD tripod. It's an absolute rock. I'm sure others can advise about the Folding HD tripod.

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OT, PM plz if you still have the Meade fork mount?

I have a couple of projects needing parts.

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Michael?

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Hello Francisico

Congratulations on your G11G and Welcome to the group. I am routinely? imaging at <1 AS RMS on G11 with 53 lb counterweight for my 10 in RC at 2040 fl using OAG. Balance is critical for me and changing to Michael Hermans high friction clutch pads was a game changer. The stock nylon clutch pads just did not work for me.

Have fun

Ron

Once I changed to the Michael Herman high friction discs I never went back. They really prevent slippage and don't come loose like the plastic ones, so you don't have to keep cranking down for them to stay put. However, they are so grippy you cannot really do a balance in RA while the mount is at the typical altitude for one's latitude needed for proper PA. But my mount is on a pier, and I can crank the altitude down to near zero so there is little downward force on the clutch assembly, and I can rock it back and forth freely to balance. If you are using a tripod, the zero-ALT position is harder to reach without tipping over or adding some hanging weights under the tripod. Still, these discs are one option for better RA stability. If RA lock is still hard to achieve, this sounds like some washer, disc or bearing in the whole assembly might be worn down to the point where a typical knob twist does not stop RA movement as there is too little contact between the mating surfaces. But the only way to check this would be to take the RA drive apart and put a micrometer on each of the parts to see if something is too thin (and with a bit of time invested).?

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John

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Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, NINA, Sequence Generator Pro and PixInsight user