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Re: Replacing the stock gearbox... interest in a metal one?
On Sun, Jun 20, 2021 at 01:47 PM, Chip Louie wrote:
Marc,I agree with the clearance needed to account for thermal contraction with changes. There are areas on the transmission train that need to give like crumple zones. I'm still not sold on spring loading the worm meshing though. I need more time. . I'll get to that once I have sorted out my couplings between the gearbox and worm shaft. |
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Re: Replacing the stock gearbox... interest in a metal one?
On Sun, Jun 20, 2021 at 07:07 AM, <pcboreland@...> wrote:
There are a number of reasons to change out the gearbox from Losmandy. I have the original ones with plastic tabs, their modified version and the 25:1 McLennan. I built my observatory early January in subzero conditions using heat plankets to set the concrete pillar etc. Having an observatory has been a game changer for me with not a single imaging night missed this year. In those winter months my rms error was 0.8 down to 0.5 arcsec rms. This was with the stock gearbox and the one piece worm on the Ra and original worm on Dec. Even with these good tracking numbers my RA was always 30% worse than Dec. So room for improvement I feel. When you look at the FFT response the 32s error was quit high at 0.2 arcsec rms or higher. Very low 76s error and the is some 240s as might be expected. The high 32s error in my mind a definite feature of the Losmandy gearbox they use and is ultimately the limiting factor on performance, assume one knocks down the 76s error. PEC does a reasonable job knocking down the 80s and 240s errors for me.Reaming works well. There isn't much material to remove and a reamer will always follow the original bore so it's very easy to do. Here's a couple of pics when I did mine last year. Close up of the motor shaft. |
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Re: Considering a GM811G
Hi Vishal,
With a few years of experience owning both a G11G and a GM8G IMO the GM811 is not the value you may think it is as there is little difference in cost but that limitation in payload is right on the edge of needing the 60 pound payload of the G11G. I bought the G11 first and the GM8 as a second mount visual only. As tiem went on I updated the 2005 vintage G11 to a full house G11G with all options available and the G11 which was no slouch but inconsistent became a reliably excellent imaging mount with low PE hot or cold and with no need to adjust as was always the case with the Losmandy original classic 2-piece drivetrain. The GM8 is a great workhorse mount and as a matter of fact I use it a lot more than the G11 because I am in a visual observing group which is always so much fun I forget that I'm an imager. I updated to the GM8 to a fully optioned GM8G and it remains a great mount but it is really not a great mount for longer imaging payloads even though it easily handles a heavy 10" LX200 SCT, C11 SCT and heavy bespoke Parallax/AT130 apo and TEC140 apos. Get the G11G for the extra few hundred dollar more, it is not a lot heavier but it is a lot more stable and will carry your 130mm apo for imaging perfectly and leave you room to move up to that big 160mm apo or RASA-11 with confidence that it will carry them for imaging without a mount change. Trust me.? -- Chip Louie Chief Daydreamer Imagination Hardware? ? ?Astropheric Weather Forecast - South Pasadena, CA? |
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Re: Meridian Flips and NINA
On Sun, Jun 27, 2021 at 07:36 PM, Edward Plumer wrote:
Paul or others more experienced in Gemini-II.? Do you know how Gemini mounts respond to the ASCOM query "CanSetPierSide".? According to Stefan, NINA first checks this property and sets the new pier side if allowed. This is usually what causes a flip. It then issues a goto back to the same target it case this fails or is not supported. Gemini.NET reports that it supports setting Side of Pier, and will ask Gemini to perform a flip when so requested. Gemini has internal logic that determines if and when a flip is possible.?
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Re: Meridian Flips and NINA
Before weather socked in, I was doing 10min subs
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On Sun, Jun 27, 2021 at 06:57 PM, Jim Waters wrote: Edward - I have been following the discussions here and on Discord.? This does need more investigation and Gemini-II innerworkings need to be explained to the NINA dev team.? ?I haven't been having issues with my setting but I don't image past 90 sec because of light pollution.? I will try to setup some daytime imaging sessions doing 10 minute subs.? There have been meridian flip coding changes in the Nightly Builds and between 1.10 HF3 and 1.11.x so any testing should focus on the current Nightly Build. ? -- Edward |
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Re: Meridian Flips and NINA
Chatted with Stefan over on NINA Discord and explained about the issue with pausing. He pointed out that even if the mount is paused, the effective Hour Angle of the *target* to which the eventual goto is performed is still progressing and it will cross the WGL, even if the direction the scope is pointing does not. So, I no longer see how this is an explanation for MF failure without other information. Your thoughts Guilherme? Paul or others more experienced in Gemini-II.? Do you know how Gemini mounts respond to the ASCOM query "CanSetPierSide".? According to Stefan, NINA first checks this property and sets the new pier side if allowed. This is usually what causes a flip. It then issues a goto back to the same target it case this fails or is not supported. -- Edward |
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Re: Meridian Flips and NINA
Just the meridian flip trigger in the advanced sequencer and the switch in the sumple sequencer?
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On Sun, Jun 27, 2021 at 11:33 AM, Jim Waters wrote: Edward - have you used the new Smart meridian Flip yet?? How do you like it? ? -- Edward |
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Re: Changing the servo motor encoders from 256 to 512 or 1024. Any reason not to do this?
I'm not Alan...but I'll pitch in some ideas...? 240 sec is the worm period of a G11 (and half the worm period of a GM8).? {Actually 239.344 sec} The term "confounded" is used in statistics to mean when several variables can have the same effect on an outcome...so you can't tell what variable is making the effect.?? The 239 sec worm period is confounded with everything that returns to it's same position at that time: 1. The worm itself...can be bad.? Try exchanging the RA and DEC worms to see which gives the lowest PE...then keep the lower one on RA. 2. The Oldham coupler.? Ideally you want the Oldham coupler input and output shafts to be exactly in the same line.? Watch for the center white plastic part movement during worm driving...if that white plastic part is moving up and down or in and out, you should try to adjust your gearbox location (or inner drive shaft location if you have a tucked motor design)? (you may have to enlarge or slot the mounting ear holes if the older direct drive design) to minimize the movement of that center white part. 3. Transfer gears can wobble if you have a tucked motor system. Don't mesh these too tightly... have no tight point. 4. Inner transfer gear drive shaft can wobble if you have a tucked motor system.?? 5. The gearbox drive shaft final gear also rotates at the same rate as the worm. Try a different gearbox. As Alan has said, the worm period of all these mounts is very long (239 sec on a G11) and can autoguide out very nicely most of the time.? It is the faster oscillation from a bad gearbox (1/7.5 of the worm period or 32 sec on a G11), or a bad RA worm bearing ball getting pinched (~78-80 sec on a G11) that really challenge autoguiding efforts. Have fun, Michael On Sun, Jun 27, 2021, 12:16 PM pcboreland via <pcboreland=[email protected]> wrote: Alan, |
Chip Louie
Paul Kanevsky
Edward Plumer
Michael Herman