Date   

Re: TheSkyX move/jog section not displayed

W. Christopher Moses
 

It's definitely ASCOM related, not me doing something silly in TSX.  Not necessarily an error, just something I'm not sure I understand. 
I posted an update on CN.


Re: RA Stiction

W. Christopher Moses
 

Good catch


Re: RA Stiction

Steve Siedentop
 

FYI -

I think the $7.50 part you’re referring to, CKSW, is the RA clutch knob spring washer, not the larger RA spring washer.

It’s not listed on their website and I had to call and order it.  They were very helpful, had them in stock, and the cost was $10.00 shipped via first class mail.

-Steve


On Thu, May 10, 2018 at 9:02 PM chris_moses@... [ESPMC-Eight] <ESPMC-Eight@...> wrote:
 

I have enough stiction in my RA that I have never really trusted my balance 100%.


Then I ran across this:


https://www.youtube.com/watch?v=F-wRj9-3pGs


Turns out, there is an easy fix for it.  It's about $7.50 on Losmandy's site.


Just a tip.

I'm waiting for mine. I'll let you know how it works



Re: RA Stiction

Jeremy Parker
 

Hi Chris,

I had the same issue, and so I did buy the wavy washer from Losmandy. I put it in, with a little wax lubricant to coat it, which hasn't seemed to migrate at all onto the clutch plate 'friction' surface. I can much more easily find my balance point, so I'd recommend it. I'd like to get one for my DEC too, just so I can move it around more easily with the clutch disengaged.

Regards,
Jeremy


RA Stiction

W. Christopher Moses
 

I have enough stiction in my RA that I have never really trusted my balance 100%.


Then I ran across this:


https://www.youtube.com/watch?v=F-wRj9-3pGs


Turns out, there is an easy fix for it.  It's about $7.50 on Losmandy's site.


Just a tip.

I'm waiting for mine. I'll let you know how it works



Re: D or V series saddle for EXOS2 ?

W. Christopher Moses
 

I think I have one of those. I'll sell it to you at a good price.
Can you send me a link to the SKU so I can make sure it is the same, please?  If you want to...

Thanks, 
Chris


TheSkyX move/jog section not displayed

W. Christopher Moses
 

Hi,

    If anyone else uses TSX, or is familiar with the ASCOM specs, please check out the following:


https://www.cloudynights.com/topic/617720-theskyx-movejog-controls-not-appearing/


I'm having a minor problem with TSX and the PMC-8



Re: Guide Graphs and Impressions

Jeremy Parker
 

Hi Ji,

OK, right, sorry about that. I think Jerry passed along the same message from Alex about the couplers. If you check out helical couplers on McMaster-Carr, you'll see the amount of allowable axial/parallel misalignment seldom exceeds 0.005-0.008". 
So if I can measure 0.017" of runout from the coupler itself, how well could that possibly work? They are cheap Chinese couplers that have secondary operations performed on them to fit the G11, while the Ruland couplers are precision-made for 1/4"-to-5mm, plug-and-play. They are expensive in single quantities, but also have clear and extensive specifications, so in my mind, they are well worth the money.

I spoke to Scott Losmandy at NEAF, and the only reason he does not use the Ruland helical beam couplers, is because they can 'wind up' and release torque suddenly if the worm binds at all, with the servo-style motors in the Gemini G11. So this is why he prefers the Oldham couplers that cannot 'store' any energy. The torque capability of the stepper motors is much less, and he agreed that these should work well for the ES G11. When there is binding, the steppers just lose steps and make an audible sound.

So for anybody looking to tune their mount and reduce PE, I can't recommend the Ruland couplers enough.

Jeremy

---In ESPMC-Eight@..., <ji.theriot@...> wrote :

Jeremy,
I am the one that posted the picture of the offset motor shat. ES is milling a new motor plate at my suggestion that has about 2mm of lateral movement along with countersunk screws, rather than the button head screws that are currently used which bracket the motor and lock it into place. Hopefully this will get the shaft in line with the worm and smooth things out.

Both of my couplers are bent and have significant run out but Alex told me that that’s the way they are designed. I showed him what you did with the Ruland couplers (although he insisted that they would not work).

I’ve also developed a 12” spike that shows up every 10 or 12 min. Not sure what that’s about.

Ji


Re: Guide Graphs and Impressions

ji.theriot@...
 

Chris,
My guide rate is set to .7 and my dec aggression is 60%. My PA is typically in the .5 range. Last night it was ~1.


Re: Guide Graphs and Impressions

ji.theriot@...
 

Jeremy,
I am the one that posted the picture of the offset motor shat. ES is milling a new motor plate at my suggestion that has about 2mm of lateral movement along with countersunk screws, rather than the button head screws that are currently used which bracket the motor and lock it into place. Hopefully this will get the shaft in line with the worm and smooth things out.

Both of my couplers are bent and have significant run out but Alex told me that that’s the way they are designed. I showed him what you did with the Ruland couplers (although he insisted that they would not work).

I’ve also developed a 12” spike that shows up every 10 or 12 min. Not sure what that’s about.

Ji


Re: Guide Graphs and Impressions

W. Christopher Moses
 

Ahhh... You said peak to peak error, not PA error.  My mistake.


Re: Guide Graphs and Impressions

Jeremy Parker
 

Hi Jerry,

Yes, I think the guiding was really good, aside from the oscillations which I think I made improvements on as the night went. Tonight is a different story, but I think it's mostly due to the seeing conditions up here in the northeast. Maybe down the road I'll think about a bigger guidescope or better guide cam.

Jeremy


Re: Guide Graphs and Impressions

Jeremy Parker
 

Yes, the seeing is pretty bad tonight, so I'm getting 0.8" RMS total, it seems. Wow, 38" peak-to-peak could be the culprit for your issues. I had a similarly bad PE, and it turned out to be a bent helical coupler, as well as more fine-tuning of the worm and bearing blocks. Have you seen my thread here or on Cloudy Nights?


Re: Guide Graphs and Impressions

W. Christopher Moses
 

Hi,
    I don't trust the PA error in PhD2. I'm working on a CN post about it right now.  I do want to learn how to use the Static Alignment tool just to compare it to other methods.

I got much better results when I set the guide rate to 0.6x.  PhD2 recommends at least 0.5x. (If you want to use 0.6x, change it in the driver. I think PhD2 will pick it up automatically)

So far, I'm getting the best results with the PPEC algorithm and 2-4 second exposures.  I find the Auto setting bounces around a lot.

Of course, that is just my set-up...

Hope that helps a little,
Chris


Re: Guide Graphs and Impressions

ji.theriot@...
 

Well I ran the guiding assistant for about 12 minutes and it recorded a 38.01" peak to peak error.  That's my first issue.  But I'm guiding with a 1.6" RMS error with 1.37" in RA.  I don't know if my guiding speed is off or what.  I've tried both sidereal and King speed but I'm not getting very good results with either.


Re: Guide Graphs and Impressions

W. Christopher Moses
 

    Well, if it makes you feel any better, I'm barely getting 1.0"  tonight.  As usuall, my dec is all over the place.  I'm going to post some info about that and PA in a separate post.
    I am imaging at a dec of almost 70. Much higher than the past few nights.


Re: Guide Graphs and Impressions

ji.theriot@...
 

Geez, I am so jealous of you guys...I just want to get below 1.0"...like once.

Ji


Re: Guide Graphs and Impressions

hubbell_jerry@...
 

Hi Jeremy,

I just read through you posts on CloudyNights. It looks like your RMS guiding in terms of pixels were < 0.15 or so which in my mind is excellent. I don't know what the limits of PHD2's centroid algorithm is, but it seems to me that you would need to change your plate scale on your guiding camera to improve it any more. I think your guide scope has a focal length of 210 mm with a plate scale of 3.68 arc-sec/px. If you could get this to around 2.5 arc-sec/px then you may still see some improved guiding, perhaps < 0.5 arc-sec total RMS.

Jerry Hubbell
Director Electrical Engineering
Explore Scientific, LLC.


Re: Guide Graphs and Impressions

W. Christopher Moses
 

Just to clarify - those numbers are in arc-sec. not pixels.


Re: Guide Graphs and Impressions

W. Christopher Moses
 

Hi,
    Thanks for the update!
    I've seen about the same thing - very good RA, good overall RMS,  but a little choppy in DEC.

    I don't have the exact numbers in front of me but Sun. my total RMS was about .6.  Last night it was up to about .75.  Both nights I was using PPEC, which seems to work better for me than hysteresis.  Both nights my DEC was higher than my RA.
    I'll try turning down the DEC aggressiveness. I don't recall exactly what it was.  I did about a 10m Guiding Assistant run and took its recommendations.

Chris

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