On Mon, Mar 17, 2025 at 08:59 AM, Mark Christensen wrote:
I violently agree with Chip on this one. To me, high resolution absolute axis encoders are just the latest example of Astro-Bling.
?
To reinforce his point on the cost issue here is a concrete example:
?
Sky-Watcher makes a mount in the 100-lb class called the EQ8. The base model, without?tripod, is about $5.3K here in the USA today.
Who knows about the future? The same model with absolute axis encoders is $9.475K. The encoders are from Renishaw, as very
well respected industrial supplier. Good, so they advertise, to 0.1 arc seconds.
?
That's a price difference of $4.175K for the encoder feature, to what end?
?
Plus, to this old man absolute encoders, USB hubs, or GPS modules integrated into a mount are just something else that can break.
As the sage said "Someday everything will need to be maintained".
?
If I want to know the coordinates of an object precisely I'll use?the Blind Astronomy Solver.
?
Mark Christensen
?
Mark,
?
WOW!? Violently?? I've had people get violent with me but until now nobody has VIOLENTLY agreed with me!? LOL!? ?
?
At retail 5 years ago a Renishaw solid 100mm encoder ring and a pair of readheads and the matching electronics cost about $3.5K PER axis.?
?
I didn't think you were old Mark.??
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
|
Re: Gemini/NINA spreadsheet
Hi Franco
This is where I left off on my latest?attempt. I decided to temporarily take N.I.N.A out of the equation?in an effort to rule it in/out. Based on this, I'm wondering if it might be a combination of Gemini-1 and ASCOM as N.I.N.A always seems to think that the mount is on the side of the pier that ASCOM is reporting.
I have a Losmandy G11 running Gemini-1 and ASCOM v7.0.2I'm using the ASCOM Gemini telescope driver version 1.1.28.0 dated Monday 9th September 2024If I look in the ASCOM Profile Explorer, the "ASCOM.GeminiTelescope.Telescope" driver has the ReportPierSide setting = TrueSlewing the scope via the Gemini software shows the pierside correctly on both sides of the pier.In the ASCOM device hub, when the mount is parked, it shows "Side of pier = West " (1)
I unpark the scope, slew to the west and the ASCOM device hub and Gemini agree (2)
I slew to the east and the ASCOM device hub and Gemini?disagree. ASCOM device hub thinks it in the west (Incorrect), and Gemini thinks it is in the east (correct).(3)
What settings do you have for reporting pierside in Gemini?
I will crank it all up later today and duplicate your settings (minus the safety?limits, obviously) and see what occurs. -- Thanks and Best Regards Neil
On Tue, Mar 18, 2025 at 1:35?AM Franco Meconi via <francomeconi= [email protected]> wrote: Hi Neil, well the update is that I tried using the info on this spreadsheet and I think I finally solved the issues with the flip. The ONLY thing I changed from what's suggested on this spreadsheet is that I switched OFF the "use side of pier" option in NINA, because flips were not reliable when I had this on. Once I switched it off I spent an entire afternoon making flips with my observatory roof closed and they all worked perfectly. However, right after that I started having a new issue which is that when I'm trying to do an imaging session the mount won't slew to a lot of objects, especially around the SCP. So I believe my settings might need some additional tweaking. Here's a couple of screenshots of my settings which seemed to work.
?
?
What issues are you dealing with exactly??
|
Re: Gemini/NINA spreadsheet
Thank you Edward. I'm still running tests so I will keep the thread updated as soon as I get any significant results. I believe east and west limits do work the same but things are a big complicated due to the physical limitations of having the RA motor on the west side for us southeners which really limits the mount movement on that side, making margins really tight. Also, what I find a bit confusing is that I noticed most posts and recommendations are to set the western go-to limit as a number which lies somewhere near 1 and say 10-15 degrees, depending on the movement margin you have on your mount, however the actual gemini 1 manual suggests values over 90 degrees, suggesting that this setting counts degrees from counter weight down position, and not backwards from the western limit? I'll do some tests using this setting (total angle from CWD) for go to limit and post results here.
?
To recap, using the suggested settings that come from your spreadsheet (for my particular limits of 95 degrees west and 114 degrees east) of 4.5 degrees western goto limit worked perfectly in achieving reliable meridian flips as long as I switched "use side of pier" OFF in NINA. However, using these restrictive settings resulted in the mount refusing to do go-tos to lots of parts in the sky, particularly around the South Celestial Pole, when trying to run an imaging session, which is somewhat inconvenient. My next test will be keeping my limits settings but changing the western go-to limit to what is suggested in the Gemini 1 manual, which is a value over 90 degrees (I'm setting it to 94 degrees, one less than my western limit). I'll post my results after tonight.
|
I violently agree with Chip on this one. To me, high resolution absolute axis encoders are just the latest example of Astro-Bling.
?
To reinforce his point on the cost issue here is a concrete example:
?
Sky-Watcher makes a mount in the 100-lb class called the EQ8. The base model, without?tripod, is about $5.3K here in the USA today.
Who knows about the future? The same model with absolute axis encoders is $9.475K. The encoders are from Renishaw, as very
well respected industrial supplier. Good, so they advertise, to 0.1 arc seconds.
?
That's a price difference of $4.175K for the encoder feature, to what end?
?
Plus, to this old man absolute encoders, USB hubs, or GPS modules integrated into a mount are just something else that can break.
As the sage said "Someday everything will need to be maintained".
?
If I want to know the coordinates of an object precisely I'll use?the Blind Astronomy Solver.
?
Mark Christensen
|
Re: Gemini/NINA spreadsheet
Franco,
?
I do not have a Gemini-1 nor experience in southern hemisphere so I cannot confirm. I would be glad to add notes to spreadsheet based on experimental findings of the group.
?
Have others used the spreadsheet as-is in southern hemisphere on Gemini-2? I would have expected the East and West limits to work the same, only physical direction of rotation of RA axis to change.?
?
--
Edward
|
Re: Gemini/NINA spreadsheet
Hi Neil, well the update is that I tried using the info on this spreadsheet and I think I finally solved the issues with the flip. The ONLY thing I changed from what's suggested on this spreadsheet is that I switched OFF the "use side of pier" option in NINA, because flips were not reliable when I had this on. Once I switched it off I spent an entire afternoon making flips with my observatory roof closed and they all worked perfectly. However, right after that I started having a new issue which is that when I'm trying to do an imaging session the mount won't slew to a lot of objects, especially around the SCP. So I believe my settings might need some additional tweaking. Here's a couple of screenshots of my settings which seemed to work.
?
?
What issues are you dealing with exactly??
|
Re: Gemini/NINA spreadsheet
I feel your?pain, Franco. I am also in the southern hemisphere, using Gemini-1 and N.I.N.A.
I'm having EXACTLY the same problem :( So I am watching?this thread with great interest !! -- Thanks and Best Regards Neil
On Sun, Mar 16, 2025 at 6:05?AM Franco Meconi via <francomeconi= [email protected]> wrote: Hi Edward, this is just what I've been looking for, I've been having a really hard time trying to config my G11 to do automated flips with NINA. I have 2 questions though, do you know if this works well with Gemini 1 as well? And also, I'm in the southern hemisphere, are there any considerations I should take into account? I read in the manual that eastern and western limits should be swapped when using the mount in the southern hemisphere, and actually due to the RA motor positioning my western limit is the "shorter" one before the setup will crash into the pier. Gemini also seems to report reversed sides of pier always, at least that's what I see in NINA: NINA will say the telescope is WEST of the pier but my telescope will be on the east. This I believe is because of me being in the southern hemisphere, because if I were to turn my mount 180 degrees in azimuth to face north, the reported side of pier would actually be correct. One would think that it would be an easy thing for Gemini to report the inverted side when your latitude is set south of the equator but this does not seem to be the case, so I wonder if there's anything I should take into account due to this. My issue with flips is that NINA will actually initiate the flip command with the legacy sequencer, but it will get stuck in an endless loop of requesting flips, once the flip is complete. Gemini will not perform another flip, but NINA will keep requesting them.
|
Very nice Moon!?
?
There are those in the OnStep group who are fascinated with very high resolution encoders.? They want to have a feed back loop that will deal with any inaccuracies that that creep into the step motor drive systems. Step motors are usually spec'ed at +/-0.05-0.09°. But these errors occur randomly and when your microstep rate is 13,653 a second they tend to cancel each other out. Nevertheless, they persist, and have found a PC mouse encoder that is fairly cheap that they are playing with. IF anyone wants to play along the thread is here:
Ultra high DPI mouse as RA sensor:
?
Currently, I believe they are using a 32bit ESP32S running at 2.4mHz to process their signals, but I stopped following the discussion a while ago.? Those of us with one foot in the grave don't have time for this. I've got too many graves to piss on.
|
Re: Help interpret my unguided log
Hi Paul,
?
Thanks for your thoughts and observations!!!
?
No idea what could cause or did cause the RA drift to reverse on 3/14.
?
The RA drift on 3/13 was about 200a/s in 40' with a PA error of 9.1. On 3/14 Drift was 140a/c in 40' with a PA error of 0.1. Better PA reduced the drift.
?
I'm currently researching RA drift discussions on CN and so far have read thoughts on the cause being atmospheric refraction and the effect of tracking rate, (Sidereal vs King) on drift. Nothing yet on reversal. Still digging...
?
And still trying to imagine how drift reverses. I've checked the guide scope/camera and I can't find anything not snugged down.
?
--
Thanks,
Topher
|
Re: Help interpret my unguided log
Hi Topher,
?
A few things I see from your PHD2 log:
?
1. There's a significant drift in RA. May be a large mirror flop, focuser sag, or just polar misalignment. It seems to reverse direction towards the end, which may mean it's more than just polar alignment error. Any thoughts as to what happened around 21:41 mark in RA when the drift changed direction?
?
?
2. Even without the reversal at 21:41, the drift is significant, something like 150 arcseconds in 40 minutes, or nearly 4 arcsecs/minute. That's a large drift that will cause the autoguider to work hard to try to correct for it.
?
3. With the drift removed, your data appears to show periodic error of about 14 arcsecs peak-to-peak, most of it at 1x the worm frequency @ 13 arcsecs and around 3 arcsecs at 2x the worm frequency. These should be easy to remove with PEC, once you fix the drift.
?
Before you try programming PEC, I'd definitely recommend that you figure out what's causing such a large drift and fix it. If you don't know the reason for the drift reversal in your data, I'd investigate that, as well.
?
Regards,
?
? ?-Paul
?
?
On Fri, Mar 14, 2025 at 03:30 PM, Topher wrote:
I do believe this is my first post!
?
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.)
?
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.
?
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!?
?
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
|
?
Here is my eclipse setup, not the heaviest payload in the G11G ever but close.? I had to rebalance by adding an additional 11 lb counterweight, 81 lbs total after adding the 2" AP Maxbright and TeleVue 35mm Panoptic to the M10 f/6.3 SCT.? I almost had to add the 21 lb instead of the 11 lb counterweight to get it to balance, note the 7 lb counterweight on the outside is almost out of counterweight shaft travel.? ?
?
?
--
Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
?
?
?
|
Re: Gemini/NINA spreadsheet
Hi Edward, this is just what I've been looking for, I've been having a really hard time trying to config my G11 to do automated flips with NINA. I have 2 questions though, do you know if this works well with Gemini 1 as well? And also, I'm in the southern hemisphere, are there any considerations I should take into account? I read in the manual that eastern and western limits should be swapped when using the mount in the southern hemisphere, and actually due to the RA motor positioning my western limit is the "shorter" one before the setup will crash into the pier. Gemini also seems to report reversed sides of pier always, at least that's what I see in NINA: NINA will say the telescope is WEST of the pier but my telescope will be on the east. This I believe is because of me being in the southern hemisphere, because if I were to turn my mount 180 degrees in azimuth to face north, the reported side of pier would actually be correct. One would think that it would be an easy thing for Gemini to report the inverted side when your latitude is set south of the equator but this does not seem to be the case, so I wonder if there's anything I should take into account due to this. My issue with flips is that NINA will actually initiate the flip command with the legacy sequencer, but it will get stuck in an endless loop of requesting flips, once the flip is complete. Gemini will not perform another flip, but NINA will keep requesting them.
|
Re: Help interpret my unguided log
Frequency tab 3/13:
?
Frequency tab 3/14:
--
Thanks,
Christopher
|
On Sat, Mar 15, 2025 at 10:46 AM, Paul Kanevsky wrote:
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).
?
The lighting during the full eclipse does have a different quality!??
?
|
Re: Help interpret my unguided log
Log and screenshots from the following night without adjustments to the entire rig:
?
--
Thanks,
Christopher
|
Re: Help interpret my unguided log
Screenshots from the 3/13 log using Auto Filter:
?   --
Thanks,
Topher
|
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.)
?
?
Doug,
?
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?
|
Wayback,
Never underestimate the challenges in getting a good image of a Lunar Eclipse.
toggle quoted message
Show quoted text
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!
?
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.)
?
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.
?
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!?
?
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
|
?
On topic, without encoders the Moon in eclipse from last night.? (I'm sure there exists better, this shot is mine.)
?
?
?
|
Chip Louie
Edward Plumer
Paul Kanevsky