PMC-EIGHT


Don Bradford
 

Wes: When the ASIAIR Pro is operating the PMC-Eight on a EXOS2 mount, is tracking controlled by the PMC-Eight? And when ASIAIR turns off tracking, does that really stop it or affect the tracking function (Tracking/Pointing) of the PMC-Eight?
-Don


--
Don Bradford
Explore Scientific AR102mm, f/6.5
EXOS2/PMC-Eight
ASIAIR Pro
ZWO ASI294MM Pro
Explore Scientific 12" Truss Tube dob


Jaimie Murdock
 

I’m not Wes, but I am a software engineer.

I believe the ASIAir Pro uses the Indilib drivers under the hood. The driver sends a command to the PMC-Eight to stop tracking, which it then executes. So the state on the PMC-Eight is changed. Same situation as ASCOM drivers - driver sends a command to hardware, hardware executes the function then sends feedback to the controller.

It’s kind of a nice fail safe - for example, if I send a park command to the mount via KStars (the observatory program I use), I can disconnect the INDI server before the park completes and the mount will still finish the park operation.

Do you suspect an issue? Wondering what motivated the question :)

--
Mount: ES PMC-8 iEXOS-100
Scope: William Optics ZenithStar 61II w/ UniGuide 32mm
Cameras: Canon EOS 1100D (Rebel T3), QHY-5-III-462C
Software: KStars on Astroberry, DeepSkyStacker and Photoshop


Don Bradford
 

No real issue that I know of yet. Thanks for responding. I’m new to the mount and controllers, but I noticed that PMCEIGHT has highly advertised tracking capability and ASIAIR has some control over mount movement. Just wondering how the ultimate tracking control is accomplished, and whether there is a potential conflict in controlling tracking. One example is that ASIAIR App may show tracking is stopped (for example after slewing to Home), but PMCEIGHT doesn’t seem to stop tracking after slewing to home under ExploreStars App. 
Don


On Sep 13, 2021, at 12:06 PM, Jaimie Murdock <jaimie.murdock@...> wrote:

I’m not Wes, but I am a software engineer.

I believe the ASIAir Pro uses the Indilib drivers under the hood. The driver sends a command to the PMC-Eight to stop tracking, which it then executes. So the state on the PMC-Eight is changed. Same situation as ASCOM drivers - driver sends a command to hardware, hardware executes the function then sends feedback to the controller.

It’s kind of a nice fail safe - for example, if I send a park command to the mount via KStars (the observatory program I use), I can disconnect the INDI server before the park completes and the mount will still finish the park operation.

Do you suspect an issue? Wondering what motivated the question :)

--
Mount: ES PMC-8 iEXOS-100
Scope: William Optics ZenithStar 61II w/ UniGuide 32mm
Cameras: Canon EOS 1100D (Rebel T3), QHY-5-III-462C
Software: KStars on Astroberry, DeepSkyStacker and Photoshop

--
Don Bradford
Explore Scientific AR102mm, f/6.5
EXOS2/PMC-Eight
ASIAIR Pro
ZWO ASI294MM Pro
Explore Scientific 12" Truss Tube dob


Wes Mcdonald
 

Don and jaimie

The pmc8 firmware has an instruction set that is sent to it by any driver.  There is an instruction that tells the mount to Track and the correct track rate is sent as a parameter.  In response the ra motor rate is set to thst passed parameter and the dec motor is stopped.   

When an application wants to go to an ra/dec coordinate, the app tells the driver where , at which point the driver computes the correct motor counts to get there.  This is a computation that has to consider the slewing behavior of the pmc8 firmware.   The driver sends a Point command to the firmware along with the place to point.   Two calls are made, one to point the ra and one to point the dec.   once these commands are sent the firmware handles the move, ramping up the mount to full slew speed, cruising for the correct amount of time and ramping back down to resume tracking at the target.

Explorestars works similarly although there are some differences in the details.

So it is not exactly  correct to say the driver manages the slew or tracking, rather the driver tells the firmware where to go and what rate to move at, and the firmware acts on those commands.   

Thus if Jaime has the wrong rate in the asiair sidereal rate input the mount will not track.

Wes



--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Don Bradford
 

Wes:  Very helpful.  So is it fair to say that we get the same quality tracking regardless of whether ASIAIR or ExploreStars is giving the commands?  Also, are the TR and PT tracking functions determined in the firmware or is that just a distinction unique to the ExploreStars?
Don

On Sep 13, 2021, at 1:59 PM, Wes Mcdonald <wesmcd6@...> wrote:

Don and jaimie

The pmc8 firmware has an instruction set that is sent to it by any driver.  There is an instruction that tells the mount to Track and the correct track rate is sent as a parameter.  In response the ra motor rate is set to thst passed parameter and the dec motor is stopped.   

When an application wants to go to an ra/dec coordinate, the app tells the driver where , at which point the driver computes the correct motor counts to get there.  This is a computation that has to consider the slewing behavior of the pmc8 firmware.   The driver sends a Point command to the firmware along with the place to point.   Two calls are made, one to point the ra and one to point the dec.   once these commands are sent the firmware handles the move, ramping up the mount to full slew speed, cruising for the correct amount of time and ramping back down to resume tracking at the target.

Explorestars works similarly although there are some differences in the details.

So it is not exactly  correct to say the driver manages the slew or tracking, rather the driver tells the firmware where to go and what rate to move at, and the firmware acts on those commands.   

Thus if Jaime has the wrong rate in the asiair sidereal rate input the mount will not track.

Wes



--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


--
Don Bradford
Explore Scientific AR102mm, f/6.5
EXOS2/PMC-Eight
ASIAIR Pro
ZWO ASI294MM Pro
Explore Scientific 12" Truss Tube dob


Harry
 

Hi Don & Wes,
I have been following your discussion, and here are a few comments, if I may. 
I have the iExos 100 PMC Eight mount. Initially, I used it very successfully with the ExploreStars app on my iPad. This was for visual and limited astrophotography with my dslr. GoTo and tracking were generally good. As I understand it, ExploreStars was initially intended for visual use.

Later, as I wanted more astrophotography capabilities, and not wanting to use a laptop, I got an ASIair Pro. I have been very happy with its performance and compatibility with the iExos 100 mount. On page 14 of the ASIair App manual, it says to “keep tracking enabled”. I have always done this and my goto and tracking have been excellent.
Since acquiring the Pro, I no longer use ExploreStars.

I guess my point is, ExploreStars and the Air both are both able to control a PMC mount. They are meant to do two different things, and how they do this I don’t know. I don’t know if one or the other are “more accurate “ than the other. To me they seem mutually exclusive. I don’t think you can (or should) use both simultaneously. If the mount is being controlled by the Air, ExploreStars is not involved. 

I would be very interested Wes, in your input.
--
Harry

Mounts: ES iExos 100-PMC Eight, ST3 Tripod

Scopes: ES  ED80CF, ES AR102,  Meade ETX 90 EC (Deforked)
Guide: ZWO 30mm Mini, ZWO ASI120MM-Mini
Software: ASIair Pro, iPad Pro, MacOS, Affinity Photo, SkySafari Plus
Cameras: ZWO 533MC Pro, Nikon D5500 (UV/IR Mod), D600
Misc: Rokinon 135mm F2 Lens, ES USB Power Bank
Filters:  Optolong L-Pro, L-eNhance






Luke
 

That's the whole purpose of the air, it does everything and does it well. It is a game changer when using ES PMC8 IMHO

Luc


From: MAIN@ESPMC-Eight.groups.io <MAIN@ESPMC-Eight.groups.io> on behalf of Harry via groups.io <flykai1@...>
Sent: September 13, 2021 8:51 PM
To: MAIN@ESPMC-Eight.groups.io <MAIN@ESPMC-Eight.groups.io>
Subject: Re: [ESPMC-Eight] PMC-EIGHT
 
Hi Don & Wes,
I have been following your discussion, and here are a few comments, if I may. 
I have the iExos 100 PMC Eight mount. Initially, I used it very successfully with the ExploreStars app on my iPad. This was for visual and limited astrophotography with my dslr. GoTo and tracking were generally good. As I understand it, ExploreStars was initially intended for visual use.

Later, as I wanted more astrophotography capabilities, and not wanting to use a laptop, I got an ASIair Pro. I have been very happy with its performance and compatibility with the iExos 100 mount. On page 14 of the ASIair App manual, it says to “keep tracking enabled”. I have always done this and my goto and tracking have been excellent.
Since acquiring the Pro, I no longer use ExploreStars.

I guess my point is, ExploreStars and the Air both are both able to control a PMC mount. They are meant to do two different things, and how they do this I don’t know. I don’t know if one or the other are “more accurate “ than the other. To me they seem mutually exclusive. I don’t think you can (or should) use both simultaneously. If the mount is being controlled by the Air, ExploreStars is not involved. 

I would be very interested Wes, in your input.
--
Harry

Mounts: ES iExos 100-PMC Eight, ST3 Tripod

Scopes: ES  ED80CF, ES AR102,  Meade ETX 90 EC (Deforked)
Guide: ZWO 30mm Mini, ZWO ASI120MM-Mini
Software: ASIair Pro, iPad Pro, MacOS, Affinity Photo, SkySafari Plus
Cameras: ZWO 533MC Pro, Nikon D5500 (UV/IR Mod), D600
Misc: Rokinon 135mm F2 Lens, ES USB Power Bank
Filters:  Optolong L-Pro, L-eNhance






--
Mounts:       ES PMC-Eight G11 - upgraded with OPWB on both RA and DEC
                     EXOS-2 GT PMC-EIGHT
Scopes:       Televue NP127IS with HSM20 and focuser boss II - Questar field model 3.5 - Takahashi FC76 classic MC Starbase Tokyo edition - Takahashi FOA60Q - Zeiss telementor - Lomo Astele 150mm
Cameras:     ZWO ASI071 PRO
                     ZWO ASI 290
Misc:            Televue 0.8 X  Focal Reducer - ZWO ASIAIR-PRO
Eyepieces:  Pentax - Masuyama - Televue - Takahashi - Vixen
Software:     Starry night PRO 8  - Nebulosity - Topaz studio - Sharp cap


Wes Mcdonald
 

Harry et al

If you have a serial connection with ascom, or kstars, or asiair then my advice is you use that for astrophotography.   Explorestars is indeed an app that is intended for visual use

That said, Explorestars is pretty versatile and some use it for astrophotography also.  You can if you desire employ phd to guide via the st4 port and use Explorestars to run the mount otherwise.  One must ensure the mount is well polar aligned and in T mode I imagine


Prior to release 2a01 of the firmware the pmc8 was only able to use its serial port or its WiFi connection but not both at once.  This is now a capability and it allows Explorestars and ascom  to coexist in a very seamless manner.  Thus you can use ascom to do all the heavy lifting and employ Explorestars as a front panel to monitor position.  It could also be used to do gotos prior to starting pulse guiding and imaging.  Similarly one can use it just as a catalog to see what is available to image.  But the best thing simultaneous use is good for us one can use the LRDU arrows in Explorestars to center up your Astro target in the frame if you are not using platesolving.  

Dual use Explorestars with asiair is not something I have tested but it likely works 
pretty well.

So the system continues to be expanded and it’s flexibility enables many different useful configurations

Wes


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Harry
 

Thank you, Wes. Very helpful.
--
Harry

Mounts: ES iExos 100-PMC Eight, ST3 Tripod

Scopes: ES  ED80CF, ES AR102,  Meade ETX 90 EC (Deforked)
Guide: ZWO 30mm Mini, ZWO ASI120MM-Mini
Software: ASIair Pro, iPad Pro, MacOS, Affinity Photo, SkySafari Plus
Cameras: ZWO 533MC Pro, Nikon D5500 (UV/IR Mod), D600
Misc: Rokinon 135mm F2 Lens, ES USB Power Bank
Filters:  Optolong L-Pro, L-eNhance






Wes Mcdonald
 

Don

Easy answer first.  P mode is unique to Explorestars.  It is useful if you have a virtual polar alignment from doing a 2 or 3 star alignment.  P mode correct the pointing position in both ra and dec 5 times per second, each time applying pointing corrections needed due to pa error, tip, tilt, and ra home error.   

T mode in explorerstars is the mount running with only the ra axis moving at the correct sidereal rate.   This is equivalent for tracking in ascom, and should be for any other driver system such as the asiair.

Wes


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Don Bradford
 

That’s very helpful. Thanks. 


On Sep 13, 2021, at 8:35 PM, Wes Mcdonald <wesmcd6@...> wrote:

Don

Easy answer first.  P mode is unique to Explorestars.  It is useful if you have a virtual polar alignment from doing a 2 or 3 star alignment.  P mode correct the pointing position in both ra and dec 5 times per second, each time applying pointing corrections needed due to pa error, tip, tilt, and ra home error.   

T mode in explorerstars is the mount running with only the ra axis moving at the correct sidereal rate.   This is equivalent for tracking in ascom, and should be for any other driver system such as the asiair.

Wes


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired

--
Don Bradford
Explore Scientific AR102mm, f/6.5
EXOS2/PMC-Eight
ASIAIR Pro
ZWO ASI294MM Pro
Explore Scientific 12" Truss Tube dob


Dino Monaco
 

Hi guys, 
Just received my Exos2 pmc8 and I’m just getting acclimated to this mount.
 I've been running my ASIAIR pro successfully with my Orion Atlas pro mount for several years so I’m quite familiar with its functionality.

Now, I’m wanting to try the ASIAIR device with the pmc8 mount. Currently, I’m using the correct serial FTDI cable.Ive inverted the chip as instructed.
Everything communicates & performs beautifully; polar alignment,  target location, plate solving. EXCEPT when I go to perform the autoGuiding sequence  in the ASIAIR app. It locates a guide star with the green box,, targets  it fine along the multi stars targets, but then fails calibration.
Tracking shows that it’s  active in ASIAIR app. And tracking rate is sidereal.

It appears ASIAIR is not sending correction data to pmc8, but I’m not certain why. So, I'm thinking it has to be a set up parameter that I’m missing. Or something.
I’m curious if anyone has experienced this issue.
Any recommendations would be much appreciated.
 Thanks, 
Dino Monaco 


Wes Mcdonald
 

Dino

The asiair guys are in the applications subgroup.  Repost there and I am sure someone familiar with the asiair will help you out


Wes


--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Harry
 

Dino, here is the link. https://espmc-eight.groups.io/g/PMC-EightApplication
--
Harry

Mounts: ES iExos 100-PMC Eight, ST3 Tripod

Scopes: ES  ED80CF, ES AR102,  Meade ETX 90 EC (Deforked)
Guide: ZWO 30mm Mini, ZWO ASI120MM-Mini
Software: ASIair Pro, iPad Pro, MacOS, Affinity Photo, SkySafari Plus
Cameras: ZWO 533MC Pro, Nikon D5500 (UV/IR Mod), D600
Misc: Rokinon 135mm F2 Lens, ES USB Power Bank
Filters:  Optolong L-Pro, L-eNhance






Dino Monaco
 

Thanks Wes. Actually, I thought I was in the Application subgroup when I posted. My bad.
But now that I have your attention, 🤓, I have a question about the tracking parameters in ExploreStars app. And in the pmc8 tracking in general for ExosII mounts.
I see in settings where the RA & Dec steps (4147200), and beneath that tracking speed and obs size. Could you briefly explain these values before I start fiddling around. 
BTW, I moved my rig over to my Atlas pro mount to rule out any issues w my ASIAIR device and everything communicates fine. So, my issue is now pointing toward why the pmc8 is not interpreting the tracking cmds from it so that auto guide can do its thing.

thanks for help in advance.
Dino


Wes Mcdonald
 

Dino

The motor count settings are the number of motor steps per full rotation of the wheel.  These values are hardware related and should be left as set by the application.   If you change those the mount will lose track of where it is pointing.   The applications make the assumptions that so many motor steps equals so many degrees of rotation.  In the case of Explorestars, ascom or the asiair drivers the steps per degree are known and used to compute sky position.

The number 47 relates to the sidereal rate being employed.  You can alter this number if you wish to make your mount run a bit faster or slower than sidereal.  For example the king rate, lunar rate.   They are all about one count away from 47 which is the sidereal rate.   If you have a g11 this number would be different owing to the drive train.  Exos2 and iexos are the same and require 47 to run at sidereal.

The firmware works fine with the asi air however you probably need to make sure you get the correct version.  Someone that  uses it can advise you, the asi air code is not supported by ES and I have no experience with it.

The thing about the exos2 is that it has dec backlash that can lead to calibration issues for guiders.   So you should adjust the dec axis to have as little as you can without binding.  Robert Hoskins wrote a tuning document that goes into (among other things) tuning up the mesh.   Look for it in the files section of the main or mounts subgroup.  Cannot remember which, might be in both places.  Even when adjusted however many users still experience backlash.  To overcome this we use camera end heavy mount weight bias, and PA error to force dec corrections to be mostly unidirectional.  This works fine unless you have wind or other disturbances that lead to dec guiding reversals.  In those conditions you might notice intervals of dec error with apparent refusal to respond to guiding pulses as the backlash is absorbed.  

Wes




--
Wes, Southport NC
EXos2-GT PMC-8, iExos 100
ES ED 127, 10" LX200GPS+wedge, Astro-Tech 8" Newt, ETX-90, 60mm no-name guide scope ~ 260mm FL
Polemaster, Orion ST-80 and SAG, ZWO 290MM, D5300 astro modified
Nina, Bootcamped Mac Mini control computer, RDP to iMAC
110 amp hour lead acid deep discharge battery for field power
Electrical Engineer, Retired


Nicholas Bodi
 

Hey Dino,

this website is amazing for everything ASIair related and will help solve your issues. They have many other posts as well, but I believe this is the article that will solve your current issues, as I was having the same. 

https://eastwindastro.blogspot.com/2021/02/how-to-adjust-asiair-guide-aggression.html?m=1

Nick


Dino Monaco
 

Thanks Wes for the explanation on those explore app parameters. I have to say after some learning on my part, that the pmc8 is truly remarkable system. I’m hoping that plate solving can be incorporated some day into explorestars. Although I don’t know if that’s possible at this time. That would eliminate the 2&3 star alignment.(Yes I’m spoiled )
I wish I had studied code back in the day.

On another note, I was doing some more investigating last night, and concluded that I don’t have an auto guiding issue at all. For whatever reason my ASIAIR is dropping out the tracking about every 15 seconds. 

This is an interesting problem and I just need to dig in deeper. I’m suspecting a cable issue at this point.

Regards,
 Dino


 

Have you selected the right baud rate. 


On 3 Oct 2021, at 16:59, Dino Monaco via groups.io <Dinomonaco@...> wrote:



Thanks Wes for the explanation on those explore app parameters. I have to say after some learning on my part, that the pmc8 is truly remarkable system. I’m hoping that plate solving can be incorporated some day into explorestars. Although I don’t know if that’s possible at this time. That would eliminate the 2&3 star alignment.(Yes I’m spoiled )
I wish I had studied code back in the day.

On another note, I was doing some more investigating last night, and concluded that I don’t have an auto guiding issue at all. For whatever reason my ASIAIR is dropping out the tracking about every 15 seconds. 

This is an interesting problem and I just need to dig in deeper. I’m suspecting a cable issue at this point.

Regards,
 Dino


--
Michael Whitaker
Wakefield, UK. 
MOUNTS. Exos-2 PMC Eight..
SCOPE: RVO Horizon 72ed. 
CAMERA: Not Applicable. 
SOFTWARE: Just iPad at moment.