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Re: Help interpret my unguided log

 

Frequency tab 3/13:
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Frequency tab 3/14:
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Thanks,
Christopher
Re: Encoders, yes or no?

 

On Sat, Mar 15, 2025 at 10:46 AM, Paul Kanevsky wrote:
What optics/camera
I used the Askar 151 (1052mm) quad element refractor with an ASI2600MC camera.? The supporting G11G works portably well with this assembly (~32 pounds on the saddle).
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The lighting during the full eclipse does have a different quality!??
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Re: Help interpret my unguided log

 

Log and screenshots from the following night without adjustments to the entire rig:
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--
Thanks,
Christopher

PHD2_GuideLog_PE_2025-03-14_140654.txt
PHD2_GuideLog_PE_2025-03-14_140654.txt

Re: Help interpret my unguided log

 

Screenshots from the 3/13 log using Auto Filter:
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--
Thanks,
Topher
Re: Encoders, yes or no?

 

On Fri, Mar 14, 2025 at 01:27 PM, WayBack wrote:
?
On topic, without encoders the Moon in eclipse from last night.? (I'm sure there exists better, this shot is mine.)
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?
Doug,
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Looks very realistic, the same as I would expect to see in the eyepiece of a good telescope. What optics/camera did you use to take the shot?
Re: Encoders, yes or no?

 

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Wayback,

Never underestimate the challenges in getting a good image of a Lunar Eclipse.

Paul




On 15 Mar 2025, at 4:27?am, WayBack <corey_d@...> wrote:

?
On topic, without encoders the Moon in eclipse from last night.? (I'm sure there exists better, this shot is mine.)
?
?
?
Help interpret my unguided log

 

I do believe this is my first post!
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The attached unguided guidelog is from my CG-11 with several upgrades including brass worm gear on RA, new OPW blocks both axis, Gemini-II w/HT motors, somewhat recent new factory RA and DEC bearings, recent clean & lube with factory grease, I hope still cleaned/dry clutch pads, clutches minimally tight, 200mmFL guidescope. About 45 minutes of unguided time under below average seeing. The PE is rather high and looks to me jaggy, (and I wonder if that's indicative of mechanical, seeing or what.)
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On a good night I see about 0.75-1.0" rms in PHD2 and am currently imaging at 1.13" and 0.75", so I'd like to see if there's anything I can do to improve performance before I buy PEMpro and create a PEC curve.
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Yesterday I removed and checked gearboxes/motors, also re-tightened oldham coupler set screws. Adjusted worm mesh but with the OPW this was just by feel - I simply push the worm into the wheel lightly and tighten everything down and if there is no stall I figure it's good - any advice appreciated!?
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Tonights experiment: if the clouds cooperate, playing with the RA worm mesh after sundown and mount cooldown as previously I'm adjusting at room temp which I know is not smart.?
--
Thanks,
Topher

PHD2_GuideLog_PE_2025-03-13_211848.txt
PHD2_GuideLog_PE_2025-03-13_211848.txt

Re: Encoders, yes or no?

 

?
On topic, without encoders the Moon in eclipse from last night.? (I'm sure there exists better, this shot is mine.)
?
?
?
Re: Encoders, yes or no?

 

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I tend to agree with you agree with you Chip - the cost of the encoders is pretty darn steep and the number of takers would likely be low.

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If folks do insist on having high res axis encoders then I guess they are probably going to look at 10-Micron or AP at costs north of about 10k or more.

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Given that a G11 and Gemini combo can deliver approx. 1 arc-seconds RMS tracking error …

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PS Ganymede subtends about 1.5 arc-seconds as seen from here.

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D.

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From: [email protected] <[email protected]> On Behalf Of Chip Louie via groups.io
Sent: 13 March 2025 20:56
To: [email protected]
Subject: Re: [Losmandy_users_io] Encoders, yes or no?

?

On Thu, Mar 13, 2025 at 03:48 AM, David C. Partridge wrote:

As would some other folks, but you have to convince Scott Losmandy to do that.? Ideally this would require a new generation of Gemini (Gemini-3?) with the necessary additional hardware and firmware to talk to the absolute encoders.?? I think it would also be possible to create a smallish additional box that would allow them to be used with the Gemini-2.??? He’d also need to supply the hardware to me as it is likely that I’d end up developing the firmware to support the encoders.

?

Adding absolute encoders to an existing mount would be a major exercise involving disassembly of the mount and quite a bit of precision machining.

?

So, if it were ever offered, I suspect it would have to be with a new version of the mount, as for most people the cost of shipping the mount back to Losmandy, paying for the work and dealing with the complication of international customs such that you only pay tax/duty on the upgrade charges when it is shipped back to you.?? In the current “trade war” those charges could be huge.

?

Please don’t discuss the politics here.

?

David?

?

The problem is not actually building a Losmandy mount with absolute encoders, I have no doubt that Losmandy could design and produce such a mount.? The problem is getting enough people to buy the resulting mount as the cost would be quite high.? Even if you simply added an RA axis encoder ring and the double read heads needed to get the required resolution your talking about doubling the cost of a G11G just for the all new mount hardware design BEFORE you get to the all new controller hardware and new version firmware you will need to run the G11G+Absolute Encoder mount.?

?

So would you pay nearly $8,000 for a 65 pound payload mount with absolute encoder RA?? Would you pay $10,000 for a dual axis absolute encoder mount that did not need guiding for the commonly used short subframe imaging we use today?? I don't think so because in reasonably skilled hands, modern autoguiding on current model G11G mounts is already good enough to produce excellent images for most sub 2,000mm focal length optics.? Not to mention that with all the money you saved you could buy an entire second imaging rig.? ? ??

?

--


Chip Louie Chief Daydreamer Imagination Hardware?

Astrospheric Forecast - South Pasadena, CA?

?

?

?
Re: Undermounted?

 

On Wed, Mar 12, 2025 at 03:32 PM, DaleN wrote:
Better! A bit of follow-up to my GM811G with poor Dec guiding for SVX140T:
?
I followed a few of the great suggestions, namely reducing the CW moment arm and Dec guiding aggressiveness.
i ordered a 21 lb CW, and installed it at the top of the shaft, with an 11 lb up against it. A 7 lb midshaft for balancing. So now at 39 lbs CW rather than 29, but much higher on shaft, so moment arm is greatly reduced.
?
dialed back the Dec Aggression to 60, and stretched the guide imaging to 3 sec from 1.5. Got down to ~.45” both RA and Dec for a while, but more generally .7” ish for each for several hours, with low eccentricity. Much better. I’ll see if I can’t dial that in better now.
?
many thanks for the suggestions!

CS, Dale
?
There are differing schools of thought on this based on what I have observed others doing and when asked why I got a lot of different answers.? IME ideally you want to use enough counterweight so you can position the counter weight mass up as high as reasonably possible (mechanical interference is the obvious limit and varies based on where you are) and still achieve good balance.? I use the small 7lb. counterweight on the end to make fine adjustments easier.? Using this method requires having the most counterweight available.??Of course the heavier the payload the more counterweights end up on the shaft and they also tend to naturally move up the shaft which is ideal.
?
?
--

Chip Louie Chief Daydreamer Imagination Hardware?

Astrospheric Forecast - South Pasadena, CA?
?
?
?
Re: Encoders, yes or no?

 

On Thu, Mar 13, 2025 at 03:48 AM, David C. Partridge wrote:

As would some other folks, but you have to convince Scott Losmandy to do that.? Ideally this would require a new generation of Gemini (Gemini-3?) with the necessary additional hardware and firmware to talk to the absolute encoders.?? I think it would also be possible to create a smallish additional box that would allow them to be used with the Gemini-2.??? He’d also need to supply the hardware to me as it is likely that I’d end up developing the firmware to support the encoders.

?

Adding absolute encoders to an existing mount would be a major exercise involving disassembly of the mount and quite a bit of precision machining.

?

So, if it were ever offered, I suspect it would have to be with a new version of the mount, as for most people the cost of shipping the mount back to Losmandy, paying for the work and dealing with the complication of international customs such that you only pay tax/duty on the upgrade charges when it is shipped back to you.?? In the current “trade war” those charges could be huge.

?

Please don’t discuss the politics here.

?

David?

?
The problem is not actually building a Losmandy mount with absolute encoders, I have no doubt that Losmandy could design and produce such a mount.? The problem is getting enough people to buy the resulting mount as the cost would be quite high.? Even if you simply added an RA axis encoder ring and the double read heads needed to get the required resolution your talking about doubling the cost of a G11G just for the all new mount hardware design BEFORE you get to the all new controller hardware and new version firmware you will need to run the G11G+Absolute Encoder mount.?
?
So would you pay nearly $8,000 for a 65 pound payload mount with absolute encoder RA?? Would you pay $10,000 for a dual axis absolute encoder mount that did not need guiding for the commonly used short subframe imaging we use today?? I don't think so because in reasonably skilled hands, modern autoguiding on current model G11G mounts is already good enough to produce excellent images for most sub 2,000mm focal length optics.? Not to mention that with all the money you saved you could buy an entire second imaging rig.? ? ??
?
--

Chip Louie Chief Daydreamer Imagination Hardware?

Astrospheric Forecast - South Pasadena, CA?
?
?
?
Re: Encoders, yes or no?

 

On Thu, Mar 13, 2025 at 02:20 PM, Chip Louie wrote:
and how it will be used.?
Exactly, practical use of the mount won't improve with more encoders than those already present, unless some use case warrants this.? And most use cases were covered with Gemini.? Given its age and enhancements, it's why it so remarkable.
Re: Encoders, yes or no?

 

On Thu, Mar 13, 2025 at 06:06 AM, WayBack wrote:
Some time ago Gemini and the digital servo made the few remaining advantages for absolutely encoders impractical.?
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Not really.? The servos just use encoders for the motor position which may or may not be well related to the actual shaft positions.? For real-time position data you need to look at shaft/axle position which the servo motors cannot actually know.?
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Absolute encoders on the shafts are absolutely possible, I have the 311,000 tic encoders on two mounts right now for use with Nexus DSC and Sky Safari.? To get serious sub arc second resolution gets very expensive depending on how much resolution and how it will be used.??
?
--

Chip Louie Chief Daydreamer Imagination Hardware?

Astrospheric Forecast - South Pasadena, CA?
?
?
?
Re: Encoders, yes or no?

 

Some time ago Gemini and the digital servo made the few remaining advantages for absolutely encoders impractical.?
Re: Encoders, yes or no?

 

开云体育

As would some other folks, but you have to convince Scott Losmandy to do that.? Ideally this would require a new generation of Gemini (Gemini-3?) with the necessary additional hardware and firmware to talk to the absolute encoders.?? I think it would also be possible to create a smallish additional box that would allow them to be used with the Gemini-2.??? He’d also need to supply the hardware to me as it is likely that I’d end up developing the firmware to support the encoders.

?

Adding absolute encoders to an existing mount would be a major exercise involving disassembly of the mount and quite a bit of precision machining.

?

So, if it were ever offered, I suspect it would have to be with a new version of the mount, as for most people the cost of shipping the mount back to Losmandy, paying for the work and dealing with the complication of international customs such that you only pay tax/duty on the upgrade charges when it is shipped back to you.?? In the current “trade war” those charges could be huge.

?

Please don’t discuss the politics here.

?

David

From: [email protected] <[email protected]> On Behalf Of jim.bachesta via groups.io
Sent: 12 March 2025 17:54
To: [email protected]
Subject: Re: [Losmandy_users_io] Encoders, yes or no?

?

I use my? upgraded 2010 Losmandy G11G for imaging. The wish list would be to improve guiding using absolute encoders.? If my understanding is correct, the E port on the Gemini-2 is not designed to support that.?

?

With that said, I would pay the dollars to add absolute encoders and placing this on the Gemini-2 road map would be fantastic.

?
Re: Undermounted?

 

Better! A bit of follow-up to my GM811G with poor Dec guiding for SVX140T:
?
I followed a few of the great suggestions, namely reducing the CW moment arm and Dec guiding aggressiveness.
i ordered a 21 lb CW, and installed it at the top of the shaft, with an 11 lb up against it. A 7 lb midshaft for balancing. So now at 39 lbs CW rather than 29, but much higher on shaft, so moment arm is greatly reduced.
?
dialed back the Dec Aggression to 60, and stretched the guide imaging to 3 sec from 1.5. Got down to ~.45” both RA and Dec for a while, but more generally .7” ish for each for several hours, with low eccentricity. Much better. I’ll see if I can’t dial that in better now.
?
many thanks for the suggestions!

CS, Dale
Re: Encoders, yes or no?

 

I use my? upgraded 2010 Losmandy G11G for imaging. The wish list would be to improve guiding using absolute encoders.? If my understanding is correct, the E port on the Gemini-2 is not designed to support that.?
?
With that said, I would pay the dollars to add absolute encoders and placing this on the Gemini-2 road map would be fantastic.
?
Re: Undermounted?

 

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Yes, always do calibration and GA each run.

Dale

On 3/3/25 11:08 PM, John Kmetz via groups.io wrote:

On Mon, Mar 3, 2025 at 04:13 PM, David Malanick wrote:
Are you doing a Calibration and Guide Assistant before every run in PHD2?
This can make all the difference. Seems more like a settings or software issue than hardware.
?
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
Re: Undermounted?

 

On Mon, Mar 3, 2025 at 04:13 PM, David Malanick wrote:
Are you doing a Calibration and Guide Assistant before every run in PHD2?
This can make all the difference. Seems more like a settings or software issue than hardware.
?
John
--
_____________________________________________________________________________________________________________________________________________________________________________

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
Re: Undermounted?

 

My setup is 27Lb, on a G11, and I have it balanced as best I can. I Keep the one 21Lb counterweight as high up as possible. It does seem to help. Same thing for me with NINA TPA and then PHD2 tells me I'm a little higher. Should be no worries on that. Are you doing a Calibration and Guide Assistant before every run in PHD2? You could run a 20-minute Guide Assist and see how it performs over time unguided. Here is a pic of where the 21lLb weight ended up on my setup.?
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