Mach1 Unable to Find Home Position Suddenly


Donald Rudny
 

Mikko,

One thing that Luca reminded me of is that if my go to is off a bit and I center and realign, when I go back to park the RA is always off a bit, but the Dec is still right on the money.  I don’t think that is your problem from what you wrote, but it is something to keep in mind.  I assume that you are not doing a recal or re-align before you go back to park.

Don

Don Rudny


On Mar 20, 2020, at 8:10 AM, Mikko Viljamaa <mikko.viljamaa@...> wrote:

Thanks Don. I have Luminous so I could try that. But... even if I just use the AP V2 driver, unpark the Mount and slew it to any direction and then ask it to park again, it will miss the park position. Any movement will confuse it now 9 times out of 10. 


- Mikko


Roland Christen
 

It always comes down to an improper time issue.

1) send the mount to a known star or object, center it and do a recal on it.
2) send the mount to Park3, let it go wherever it goes.
3) check your time, daylight savings, time zone, date and location. One of them will be wrong.
4) If the Park3 is off by 15 degrees, the time is off by 1 hour. Change the time by 1 hour and send the mount to Park3. You will see that the mount will now park 15 degrees in one direction or other.
5) the fact that you changed the time by 1 hour will not impact the mount's ability to go back exactly to the same star or object that you previously centered and recaled on. As long as you don't loosen the clutches and physically move the axes.

Do the above sequence, and it should provide you with the knowledge about how mounts work and what function time has. Basically once you point the scope to an object and do a recal (or sync), then your mount's time, daylight savings, time zone will determine where the meridian line is and thus where Park3 is.

Park3 is wholly governed by where the meridian line is and that is a function of time. The meridian line is prominently displayed on the ASCOM driver at the top with the heading LST (Local Sidereal Time). Your local sidereal time is calculated from your time entries and should correspond to Universal Time minus your time zone. So it is easy for you to check to see that it is correct. If not, you can make the proper time and time zone setting changes that will tell the mount the correct information in order to always park itself accurately.

Rolando



-----Original Message-----
From: Mikko Viljamaa <mikko.viljamaa@...>
To: main <main@ap-gto.groups.io>
Sent: Fri, Mar 20, 2020 1:10 pm
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Thanks Don. I have Luminous so I could try that. But... even if I just use the AP V2 driver, unpark the Mount and slew it to any direction and then ask it to park again, it will miss the park position. Any movement will confuse it now 9 times out of 10. 


- Mikko


Mikko Viljamaa
 

Thanks Rolando, I have checked those a few times now. And if one of them would be incorrect, wouldn't the Mount always miss the position by the same 15 degrees or what not. Now the mount occasionally gets the park-3 correct. I keep checking but I'm pretty sure all the initial data is correct.


- Mikko


Roland Christen
 

The mount will always park according to the LST that the ASCOM driver calculates based on your time, date, location data. If it parks wrong, look at your LST number. Park2 and 3 are always 6 hours from LST. Park 1 , 4 and 5 are always at LST.

LST is your local sidereal time as calculated by the ASCOM driver from your local time that you input to the driver plus your time zone, your daylight savings setting, your longitude and of course your date.

When you slew to an object and it is off by 5 degrees, your inclination then is to move the mount 5 degrees to center the object and recal. When you do that you are actually shifting the entire sky including the overhead hour angle (LST or meridian line) by that same 5 degrees, and along with it all the park positions.

Is this a problem? Not really unless you specifically must have the mount park within a few arc seconds so that your rolloff roof clears the scope. Your time may be off for this session, but when you open up the next session it is not the exact time that determines where the sky objects are, it is the time difference. Therefore, objects will be centered even though the exact time is off as long as the time difference is correct.

This occurs dramatically twice a year when the time changes by 1 hour. If you forget to also change the daylight savings number by 1 hour then the time difference between the last session and the one after the 1 hour time change will be off by 1 hour. Then all sky objects will be 15 degrees in error, so then when you move the scope and recal or sync, you inadvertently also move the meridian line by 15 degrees and all parks accordingly. This is the most common effect that time has on the mount.

Roland



-----Original Message-----
From: Mikko Viljamaa <mikko.viljamaa@...>
To: main <main@ap-gto.groups.io>
Sent: Fri, Mar 20, 2020 5:11 pm
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Thanks Rolando, I have checked those a few times now. And if one of them would be incorrect, wouldn't the Mount always miss the position by the same 15 degrees or what not. Now the mount occasionally gets the park-3 correct. I keep checking but I'm pretty sure all the initial data is correct.


- Mikko


Mikko Viljamaa
 

Thanks Roland, i'm trying to digest this as I don't recall ever changing anything after the day light saving change. Nor would I know where to do that. Here's a screen capture from a few minutes ago. I don't see anything extraordinary here but if the LST time should be 6 hours from the park 3, then that is not correct as currently it should be two hours less than shown. If this is the issue, how do I fix that?


Thanks,

Mikko


Ray Gralak
 

Hi Mikko,

Thanks Roland, i'm trying to digest this as I don't recall ever changing anything after the day light saving change.
Nor would I know where to do that. Here's a screen capture from a few minutes ago. I don't see anything
extraordinary here but if the LST time should be 6 hours from the park 3, then that is not correct as currently it
should be two hours less than shown. If this is the issue, how do I fix that?
The screenshot of the driver shows RA=0 and Dec=90, implying the mount has not yet been initialized. That would be a good reason for the LST to be wrong. The mount needs to be initialized before LST will be accurate.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Mikko Viljamaa
Sent: Friday, March 20, 2020 5:17 PM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Thanks Roland, i'm trying to digest this as I don't recall ever changing anything after the day light saving change.
Nor would I know where to do that. Here's a screen capture from a few minutes ago. I don't see anything
extraordinary here but if the LST time should be 6 hours from the park 3, then that is not correct as currently it
should be two hours less than shown. If this is the issue, how do I fix that?


Thanks,

Mikko


Ray Gralak
 

Hi Don,

I’m not a computer expert and hate Windows, but I understand that a driver can get corrupted. Using Luminous
This is not likely the issue. The driver and associated applications have a digital signature that will detect corruption.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Donald Rudny
Sent: Friday, March 20, 2020 11:30 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Mikko,

I’m not a computer expert and hate Windows, but I understand that a driver can get corrupted. Using Luminous
directly would take the AP V2 driver out of the control system, wouldn’t it? If it’s still off on the park with just
Luminous, then there is a mount or CP problem. If it works ok, then something is amiss in your
computer/driver/APCC. You should be able to initialize with just Luminous. Not sure what park positions it allows
for. SkySafari only allows for Park 4. I think they are working to allow for more.

Don

Don Rudny



On Mar 20, 2020, at 8:10 AM, Mikko Viljamaa <mikko.viljamaa@gmail.com> wrote:



Thanks Don. I have Luminous so I could try that. But... even if I just use the AP V2 driver, unpark the Mount
and slew it to any direction and then ask it to park again, it will miss the park position. Any movement will confuse
it now 9 times out of 10.


- Mikko


Donald Rudny
 

Hi Ray,

Like I said, I’m not a computer expert, but I was a test engineer, so I know one of the best ways to troubleshoot is to eliminate components out of a system if you can to see how things react. My suggestion in this case is a simple one to try. Mikko thinks it’s his mount. Using Luminous and eliminating his computer and APCC would determine that. If it still has the problem then at least we know it’s not the software or driver. Just trying to help.

Don

Don Rudny

On Mar 20, 2020, at 3:51 PM, Ray Gralak <groups3@gralak.com> wrote:

Hi Don,

I’m not a computer expert and hate Windows, but I understand that a driver can get corrupted. Using Luminous
This is not likely the issue. The driver and associated applications have a digital signature that will detect corruption.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Donald Rudny
Sent: Friday, March 20, 2020 11:30 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Mikko,

I’m not a computer expert and hate Windows, but I understand that a driver can get corrupted. Using Luminous
directly would take the AP V2 driver out of the control system, wouldn’t it? If it’s still off on the park with just
Luminous, then there is a mount or CP problem. If it works ok, then something is amiss in your
computer/driver/APCC. You should be able to initialize with just Luminous. Not sure what park positions it allows
for. SkySafari only allows for Park 4. I think they are working to allow for more.

Don

Don Rudny



On Mar 20, 2020, at 8:10 AM, Mikko Viljamaa <mikko.viljamaa@gmail.com> wrote:



Thanks Don. I have Luminous so I could try that. But... even if I just use the AP V2 driver, unpark the Mount
and slew it to any direction and then ask it to park again, it will miss the park position. Any movement will confuse
it now 9 times out of 10.


- Mikko




Mikko Viljamaa
 

Ray when you say, initialized, what exactly do you mean?


- Mikko


Roland Christen
 

When the mount is parked the RA and Dec will not register. Unpark the mount from Park3 and look at the LST and the RA. They should be 6 hours apart.

Rolando



-----Original Message-----
From: Mikko Viljamaa <mikko.viljamaa@...>
To: main <main@ap-gto.groups.io>
Sent: Fri, Mar 20, 2020 7:16 pm
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Thanks Roland, i'm trying to digest this as I don't recall ever changing anything after the day light saving change. Nor would I know where to do that. Here's a screen capture from a few minutes ago. I don't see anything extraordinary here but if the LST time should be 6 hours from the park 3, then that is not correct as currently it should be two hours less than shown. If this is the issue, how do I fix that?


Thanks,

Mikko


Ray Gralak
 

Ray when you say, initialized, what exactly do you mean?
When the mount is first powered on it will report RA=0 Dec=90. This indicates that the mount needs to be initialized. That's what your screen shot of the driver shows. Initialization is the process of setting import parameters like time, time zone, longitude and latitude, and then unparking the mount. The mount should be set to be unparked from "last parked position" and not one of the park positions.

The driver should initialize the mount when it sees those values but for some reason it doesn't appear to be initialized on your screen shot. The only other explanation might be that you have slewed the mount to exactly RA=0 Dec=90?

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Mikko Viljamaa
Sent: Saturday, March 21, 2020 6:43 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Ray when you say, initialized, what exactly do you mean?


- Mikko


Roland Christen
 

Unpark will initialize the mount.

Roland



-----Original Message-----
From: Mikko Viljamaa <mikko.viljamaa@...>
To: main <main@ap-gto.groups.io>
Sent: Sat, Mar 21, 2020 8:43 am
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Ray when you say, initialized, what exactly do you mean?


- Mikko


Mikko Viljamaa
 

Thanks Ray & Rolando,

So as long as I have had the Mount, about two years now I have never used park from the last position - this without any issue. I did go out and tried both; unpark from 3 and park back to 3 results the Dec axes to miss its mark about an inch. I then manually swung the Dec to match the mark and chose to unpark from the last position. Did a slew and sure thing, the mount returned to park 3 nicely. I then did the same exercise a dozen times and the worst Dec miss was maybe a quarter of an inch - which I have seen before and I'm not worried about. I might have a narrow window tonight to see how things go in real life and if the mount points where expected and Platesolve finds the target immediately, 

The LST / RA difference is off about 2 minutes, is this an issue?




- Mikko


Dale Ghent
 

The accuracy of your PC clock and, by extension, the clock in the mount control box, is crucial regardless of the situation.

I presume you are initializing the mount using the A-P ASCOM driver from your PC (that means if your hand controller is connected to the mount, it is in EXT mode and you do no select the location info to initialize with from it.)

First, ensure that your ASCOM driver has the "sync PC time to mount" option set.

Second, ensure that your PC's clock is accurate. I know it's common to have observatory computers cut off from the network, which means that they cannot avail themselves to the services of NTP servers that any modern OS will automatically try to connect to. If you choose to have your PC cut off in such a way, you will need to sync it from an external source such as a GPS or keep adjusting the time by hand. if your PC is connected to the internet, ensure that Windows is syncing to NTP servers. On Windows 10, that would mean going to Date & Time settings and ensuring that "Set time automatically" is set to On.

If you don't have an accurate time app on your mobile phone, you can quickly call the US Naval Observatory master clock at +1 202-762-1069 for an automated readout and prompting of the current time down to the second. There is a service for Mountain time at +1 719-567-6742.

/dale

On Mar 21, 2020, at 10:56 AM, Mikko Viljamaa <mikko.viljamaa@gmail.com> wrote:

Thanks Ray & Rolando,

So as long as I have had the Mount, about two years now I have never used park from the last position - this without any issue. I did go out and tried both; unpark from 3 and park back to 3 results the Dec axes to miss its mark about an inch. I then manually swung the Dec to match the mark and chose to unpark from the last position. Did a slew and sure thing, the mount returned to park 3 nicely. I then did the same exercise a dozen times and the worst Dec miss was maybe a quarter of an inch - which I have seen before and I'm not worried about. I might have a narrow window tonight to see how things go in real life and if the mount points where expected and Platesolve finds the target immediately,

The LST / RA difference is off about 2 minutes, is this an issue?




- Mikko

<View recent photos.png>


Roland Christen
 


The LST / RA difference is off about 2 minutes, is this an issue?
As soon as you initialize, the RA axis will begin tracking and the LST/RA difference will increase 15 arc sec per second (when the mount is in Sidereal tracking mode). If you put the mount in STOP mode, the LST/RA will remain constant.

Roland


-----Original Message-----
From: Mikko Viljamaa <mikko.viljamaa@...>
To: main <main@ap-gto.groups.io>
Sent: Sat, Mar 21, 2020 9:56 am
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Thanks Ray & Rolando,

So as long as I have had the Mount, about two years now I have never used park from the last position - this without any issue. I did go out and tried both; unpark from 3 and park back to 3 results the Dec axes to miss its mark about an inch. I then manually swung the Dec to match the mark and chose to unpark from the last position. Did a slew and sure thing, the mount returned to park 3 nicely. I then did the same exercise a dozen times and the worst Dec miss was maybe a quarter of an inch - which I have seen before and I'm not worried about. I might have a narrow window tonight to see how things go in real life and if the mount points where expected and Platesolve finds the target immediately, 

The LST / RA difference is off about 2 minutes, is this an issue?




- Mikko


Mikko Viljamaa
 

Thanks Dale. I don't own a hand controller, never saw the need for it. Every time I have checked the time it's the same in all computers. But to your point, I'm suspecting that the time is the possible contributor here as the Mount misses its park always about the same. So I don't know if something changes or if something gets updated at some point bur for sure as said, I have not had issues like this in the past two years.


- Mikko


Ray Gralak
 

The LST / RA difference is off about 2 minutes, is this an issue?
Park 3 is on purpose not exactly at the celestial pole, but close. So, that's okay.

Did a slew and sure thing, the mount returned to park 3 nicely. I then did the same exercise a dozen times and the
worst Dec miss was maybe a quarter of an inch - which I have seen before and I'm not worried about.
It seems like unparking from last parked position has solved the problem, correct? It's always safer to unpark from the last parked position than to unpark from one of the park positions.

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Mikko Viljamaa
Sent: Saturday, March 21, 2020 7:56 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Thanks Ray & Rolando,

So as long as I have had the Mount, about two years now I have never used park from the last position - this
without any issue. I did go out and tried both; unpark from 3 and park back to 3 results the Dec axes to miss its
mark about an inch. I then manually swung the Dec to match the mark and chose to unpark from the last position.
Did a slew and sure thing, the mount returned to park 3 nicely. I then did the same exercise a dozen times and the
worst Dec miss was maybe a quarter of an inch - which I have seen before and I'm not worried about. I might have
a narrow window tonight to see how things go in real life and if the mount points where expected and Platesolve
finds the target immediately,

The LST / RA difference is off about 2 minutes, is this an issue?




- Mikko


Mikko Viljamaa
 

Well it seems that "park from the last position" was the cure and yesterday evening the Mount slewed were it was supposed to and plate solved the first image in seconds as before this whole episode started. I would still like to understand what has changed and why suddenly unpark from #3 is not working anymore. Does the success of unparking from the last position tell us anything? Meanwhile when smarter people than I are pondering this, I want to thank everyone who participated to this conversation and proposed different things to try or consider.


Thanks,

Mikko


Ray Gralak
 

Hi Mikko,

Well it seems that "park from the last position" was the cure and yesterday evening the Mount slewed were it was
supposed to and plate solved the first image in seconds as before this whole episode started. I would still like to
understand what has changed and why suddenly unpark from #3 is not working anymore. Does the success of
unparking from the last position tell us anything? Meanwhile when smarter people than I are pondering this, I
want to thank everyone who participated to this conversation and proposed different things to try or consider.
After you recal/sync the mount via a platesolve and return to one of the park positions it can appear to be in the wrong position under certain conditions such as:

* The pier/tripod is not perpendicular to the earth's center.
* The mount is not "perfectly" polar aligned
* The optical axis is not aligned with the mount's mechanical axis.

So thinking the mount was in the wrong position one might be tempted to "fix" the mount be loosening the clutches and putting the mount back in the "correct" position then unparking from that park position. Doing that will actually cause the mount to be in the wrong position.

By just resuming from last parked position the mount should be exactly where it left off when last park. In fact both the AP V2 driver and APCC should warn you that it will set "unpark to last position" when you try to unpark from one of the park positions. That's to prevent people from making a mistake and accidentally unparking from the wrong park position. You should always use "unpark from last park position" if you have not moved/declutched the mount/scope since the last time you parked it. Of course if you are setting up the mount in a new location, or declutched and manually moved the scope to a new park position, it is appropriate to unpark from one of the park positions to start off.

BTW, this implies the mount is not a Mach 2. Since the Mach 2 always knows it's RA/Dec mechanical orientation you can only "unpark from last park position". :-)

-Ray Gralak
Author of APCC (Astro-Physics Command Center): https://www.astro-physics.com/apcc-pro
Author of PEMPro V3: https://www.ccdware.com
Author of Astro-Physics V2 ASCOM Driver: https://www.siriusimaging.com/apdriver


-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Mikko Viljamaa
Sent: Sunday, March 22, 2020 5:36 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] Mach1 Unable to Find Home Position Suddenly

Well it seems that "park from the last position" was the cure and yesterday evening the Mount slewed were it was
supposed to and plate solved the first image in seconds as before this whole episode started. I would still like to
understand what has changed and why suddenly unpark from #3 is not working anymore. Does the success of
unparking from the last position tell us anything? Meanwhile when smarter people than I are pondering this, I
want to thank everyone who participated to this conversation and proposed different things to try or consider.


Thanks,

Mikko


Dominique Durand
 
Edited

Hi Mikko,
Frankly, nothing simpler on a Mach1 I still have the CP3 and I also had a CP4 with a station made with the keypad. Since I am near the meridian of Geenwich I chose to operate in UT (PC and Keypad) with the correct GPS coordinates from where I am. Either the frame is already parked and it stands out (I chose this option) upon ignition with a polar alignment possibly done with the RAPAS or with the routine polaris +1 star on the keypad if I was not in fixed pose. As I had concerns with the local time at the beginning, the best for me was to operate in UT keypad and PC.In the event of non-prior parking, this seems simple nevertheless. Once the mount is on and oriented to the north compass, we put it in park3 for example, we position the mount (Disengaging the brakes) to be in the park3 position and we apply the brakes. Then we do a goto on an easily identifiable star, we synchronize on the keypad and then we redo a park3 to see where the mount is parked. We turn off then on. unpark is automatic (If provided) and then just choose an object and do goto ... we are on it or we are not far ...If on the keypad the GPS coordinates and the Dates / times are OK this can only work ...
Thank you to Roland and his team A.P. for offering us frames that manage so simply.

Dominique