Mach1 RA guiding spike


yanzhe liu
 

Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 


Roland Christen
 

Since they are all exactly the same heights it appears to be dither moves.
Re-mesh won't do anything, so don't mess with it at this time, until you find out for sure what causes these moves. Check your log files and look for move commands at those points.

Rolando



-----Original Message-----
From: yanzhe liu <liuyanzhe@...>
To: main@ap-gto.groups.io
Sent: Fri, Jan 21, 2022 12:08 pm
Subject: [ap-gto] Mach1 RA guiding spike

Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 

--
Roland Christen
Astro-Physics


 

can you upload your guidelog? 

screen capture isn't helpful to diagnose this behavior



On Fri, Jan 21, 2022 at 10:09 AM yanzhe liu <liuyanzhe@...> wrote:
Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 



--
Brian 



Brian Valente


yanzhe liu
 

Brian,


Roland,

The spikes were between dithers, so dither should not be the problem.
One of my friends said he had similar issue on his AP mount, and cleaning/re-gease the gear fixed the issue. Do you think mine looks the same?

Thanks

Yanzhe

On Fri, Jan 21, 2022 at 10:35 AM Brian Valente <bvalente@...> wrote:
can you upload your guidelog? 

screen capture isn't helpful to diagnose this behavior



On Fri, Jan 21, 2022 at 10:09 AM yanzhe liu <liuyanzhe@...> wrote:
Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 



--
Brian 



Brian Valente


yanzhe liu
 

I swapped the scope/CCD with another system, both systems worked fine. So it is not clear to me what the problem was, whether it was mount or mount+scope/ccd, or something else.

Brian,

Did you see anything wrong in the log?

Roland,

How often should mach1 be cleaned/re-geased/re-meshed?

Yanzhe

On Fri, Jan 21, 2022 at 11:06 AM yanzhe liu via groups.io <liuyanzhe=gmail.com@groups.io> wrote:
Brian,


Roland,

The spikes were between dithers, so dither should not be the problem.
One of my friends said he had similar issue on his AP mount, and cleaning/re-gease the gear fixed the issue. Do you think mine looks the same?

Thanks

Yanzhe

On Fri, Jan 21, 2022 at 10:35 AM Brian Valente <bvalente@...> wrote:
can you upload your guidelog? 

screen capture isn't helpful to diagnose this behavior



On Fri, Jan 21, 2022 at 10:09 AM yanzhe liu <liuyanzhe@...> wrote:
Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 



--
Brian 



Brian Valente


Roland Christen
 

If it's working, don't mess with it. Re-greasing is not needed unless you run it every night for the next 5 years.

Rolando

-----Original Message-----
From: yanzhe liu <liuyanzhe@...>
To: main@ap-gto.groups.io
Sent: Tue, Jan 25, 2022 5:46 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

I swapped the scope/CCD with another system, both systems worked fine. So it is not clear to me what the problem was, whether it was mount or mount+scope/ccd, or something else.

Brian,

Did you see anything wrong in the log?

Roland,

How often should mach1 be cleaned/re-geased/re-meshed?

Yanzhe

On Fri, Jan 21, 2022 at 11:06 AM yanzhe liu via groups.io <liuyanzhe=gmail.com@groups.io> wrote:
Brian,


Roland,

The spikes were between dithers, so dither should not be the problem.
One of my friends said he had similar issue on his AP mount, and cleaning/re-gease the gear fixed the issue. Do you think mine looks the same?

Thanks

Yanzhe

On Fri, Jan 21, 2022 at 10:35 AM Brian Valente <bvalente@...> wrote:
can you upload your guidelog? 

screen capture isn't helpful to diagnose this behavior



On Fri, Jan 21, 2022 at 10:09 AM yanzhe liu <liuyanzhe@...> wrote:
Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics


yanzhe liu
 

Roland,

I noticed there is some gap on the base ( Highlighted in red) if I wobble my telescope. Shall I tightens green screws I order to fix it?

Yanzhe

On Jan 25, 2022, at 4:11 PM, Roland Christen via groups.io <chris1011@...> wrote:


If it's working, don't mess with it. Re-greasing is not needed unless you run it every night for the next 5 years.

Rolando

-----Original Message-----
From: yanzhe liu <liuyanzhe@...>
To: main@ap-gto.groups.io
Sent: Tue, Jan 25, 2022 5:46 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

I swapped the scope/CCD with another system, both systems worked fine. So it is not clear to me what the problem was, whether it was mount or mount+scope/ccd, or something else.

Brian,

Did you see anything wrong in the log?

Roland,

How often should mach1 be cleaned/re-geased/re-meshed?

Yanzhe

On Fri, Jan 21, 2022 at 11:06 AM yanzhe liu via groups.io <liuyanzhe=gmail.com@groups.io> wrote:
Brian,


Roland,

The spikes were between dithers, so dither should not be the problem.
One of my friends said he had similar issue on his AP mount, and cleaning/re-gease the gear fixed the issue. Do you think mine looks the same?

Thanks

Yanzhe

On Fri, Jan 21, 2022 at 10:35 AM Brian Valente <bvalente@...> wrote:
can you upload your guidelog? 

screen capture isn't helpful to diagnose this behavior



On Fri, Jan 21, 2022 at 10:09 AM yanzhe liu <liuyanzhe@...> wrote:
Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics


Roland Christen
 

Yes, you can snug down on the screws on the sides of the base. Don't use gorilla strength, just enough snugging until the wobble goes away.

Roland

-----Original Message-----
From: yanzhe liu <liuyanzhe@...>
To: main@ap-gto.groups.io
Sent: Sat, Jan 29, 2022 1:37 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

Roland,

I noticed there is some gap on the base ( Highlighted in red) if I wobble my telescope. Shall I tightens green screws I order to fix it?

Yanzhe

On Jan 25, 2022, at 4:11 PM, Roland Christen via groups.io <chris1011@...> wrote:


If it's working, don't mess with it. Re-greasing is not needed unless you run it every night for the next 5 years.

Rolando

-----Original Message-----
From: yanzhe liu <liuyanzhe@...>
To: main@ap-gto.groups.io
Sent: Tue, Jan 25, 2022 5:46 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

I swapped the scope/CCD with another system, both systems worked fine. So it is not clear to me what the problem was, whether it was mount or mount+scope/ccd, or something else.

Brian,

Did you see anything wrong in the log?

Roland,

How often should mach1 be cleaned/re-geased/re-meshed?

Yanzhe

On Fri, Jan 21, 2022 at 11:06 AM yanzhe liu via groups.io <liuyanzhe=gmail.com@groups.io> wrote:
Brian,


Roland,

The spikes were between dithers, so dither should not be the problem.
One of my friends said he had similar issue on his AP mount, and cleaning/re-gease the gear fixed the issue. Do you think mine looks the same?

Thanks

Yanzhe

On Fri, Jan 21, 2022 at 10:35 AM Brian Valente <bvalente@...> wrote:
can you upload your guidelog? 

screen capture isn't helpful to diagnose this behavior



On Fri, Jan 21, 2022 at 10:09 AM yanzhe liu <liuyanzhe@...> wrote:
Repost as my original post did not seem to go through.

Just noticed something abnormal with my Mach1 guiding. There were spikes on RA guiding. Sometimes it runs fine for a couple of hours, sometimes a spike comes every few minutes like the attached screenshot below..
 
Each pixel is ~4" so spike is ~10".
 
What could be the problem? There is no noticeable backlash on RA/DEC. RA/DEC are well balanced. Do I need to re-mesch RA, or something is wrong with gearbox?
 


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


fernandorivera3
 

Yanzhe is the mount an older, used one??

Fernando


Suresh Mohan
 

Do u have a huge backlash ?


On Jan 30, 2022, at 1:55 PM, fernandorivera3 via groups.io <fernandorivera3@...> wrote:

Yanzhe is the mount an older, used one??

Fernando


Daeone
 

I would check if there is any wobble component is present or cables management.
1. is guide telescope or cam mounted (tightened) correctly. (sometimes it can be happen because of incorrect bolt size(too long) to tighten guide telescope)
2. need to check if there is any cable which is hitting during tracking..


yanzhe liu
 

Roland,

Are there 2 or 3 screws? I saw 2. Is there another one hidden behind Alt adjustment knobs?


yanzhe liu
 

There is no backlash.
I am using OAG and it has never had any issue.


 

Hi Yanzhe

I had a chance to go through your guidelog and have a few observations. I think you still need to track down the source, but we can probably rule out a few things

I don't think it's in the guiding: they happen independent of dithers and they are instantaneous, so guide pulses are causing these

I don't think it's mechanical, or at least part of the gearing: there is no clear periodicity to them, and they happen in very limited circumstances (in 6 1/2 hours of guiding i counted 6 total, all relatively close in time together)

this is the time between the spikes (in secs):
261
139
155
575
90

I did notice it only appeared to happen when the mount was pier side west, so it could be something related to shifting equipment, snags, etc.

you might try replicating that pointing position and see if it repeats in the same place @ Hour angle = -1.20 hr, Pier side = West,  Alt = 50.0 deg, Az = 151.1 deg

if it does, try disabling guiding and see if it shows up in unguided output

Also the guidelog did not include a calibration run or a guiding assistant (unguided output) so those would be helpful to include if you post a guidelog again



On Mon, Jan 31, 2022 at 11:14 AM yanzhe liu <liuyanzhe@...> wrote:
There is no backlash.
I am using OAG and it has never had any issue.



--
Brian 



Brian Valente


Roland Christen
 

There are 2.

Roland



-----Original Message-----
From: yanzhe liu <liuyanzhe@...>
To: main@ap-gto.groups.io
Sent: Mon, Jan 31, 2022 1:10 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

Roland,

Are there 2 or 3 screws? I saw 2. Is there another one hidden behind Alt adjustment knobs?

--
Roland Christen
Astro-Physics


Roland Christen
 

If it's a snag it will show up during an unguided exposure as a shift rather than a spike in the guider graph. Whenever you are troubleshooting a problem, guided data is not useful because guiding tends to hide or compensate for an anomaly. That's why I always want to see unguided data if possible.

Same is true of star images that have defects. Defocus the image of the star and this can instantly tell where the problem lies, whether it's in the main optics or somewhere further down the imaging train.

Rolando

-----Original Message-----
From: Brian Valente <bvalente@...>
To: main@ap-gto.groups.io
Sent: Mon, Jan 31, 2022 1:34 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

Hi Yanzhe

I had a chance to go through your guidelog and have a few observations. I think you still need to track down the source, but we can probably rule out a few things

I don't think it's in the guiding: they happen independent of dithers and they are instantaneous, so guide pulses are causing these

I don't think it's mechanical, or at least part of the gearing: there is no clear periodicity to them, and they happen in very limited circumstances (in 6 1/2 hours of guiding i counted 6 total, all relatively close in time together)

this is the time between the spikes (in secs):
261
139
155
575
90

I did notice it only appeared to happen when the mount was pier side west, so it could be something related to shifting equipment, snags, etc.

you might try replicating that pointing position and see if it repeats in the same place @ Hour angle = -1.20 hr, Pier side = West,  Alt = 50.0 deg, Az = 151.1 deg

if it does, try disabling guiding and see if it shows up in unguided output

Also the guidelog did not include a calibration run or a guiding assistant (unguided output) so those would be helpful to include if you post a guidelog again



On Mon, Jan 31, 2022 at 11:14 AM yanzhe liu <liuyanzhe@...> wrote:
There is no backlash.
I am using OAG and it has never had any issue.


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics


 

>>> That's why I always want to see unguided data if possible.

yes agreed on that

Another possibility i've seen (not on AP mounts but others) is a bad PEC. If you see the spikes behavior during unguided you can also disable PEC during unguided capture to see if that addresses it



On Mon, Jan 31, 2022 at 12:16 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
If it's a snag it will show up during an unguided exposure as a shift rather than a spike in the guider graph. Whenever you are troubleshooting a problem, guided data is not useful because guiding tends to hide or compensate for an anomaly. That's why I always want to see unguided data if possible.

Same is true of star images that have defects. Defocus the image of the star and this can instantly tell where the problem lies, whether it's in the main optics or somewhere further down the imaging train.

Rolando

-----Original Message-----
From: Brian Valente <bvalente@...>
To: main@ap-gto.groups.io
Sent: Mon, Jan 31, 2022 1:34 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

Hi Yanzhe

I had a chance to go through your guidelog and have a few observations. I think you still need to track down the source, but we can probably rule out a few things

I don't think it's in the guiding: they happen independent of dithers and they are instantaneous, so guide pulses are causing these

I don't think it's mechanical, or at least part of the gearing: there is no clear periodicity to them, and they happen in very limited circumstances (in 6 1/2 hours of guiding i counted 6 total, all relatively close in time together)

this is the time between the spikes (in secs):
261
139
155
575
90

I did notice it only appeared to happen when the mount was pier side west, so it could be something related to shifting equipment, snags, etc.

you might try replicating that pointing position and see if it repeats in the same place @ Hour angle = -1.20 hr, Pier side = West,  Alt = 50.0 deg, Az = 151.1 deg

if it does, try disabling guiding and see if it shows up in unguided output

Also the guidelog did not include a calibration run or a guiding assistant (unguided output) so those would be helpful to include if you post a guidelog again



On Mon, Jan 31, 2022 at 11:14 AM yanzhe liu <liuyanzhe@...> wrote:
There is no backlash.
I am using OAG and it has never had any issue.


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics



--
Brian 



Brian Valente


yanzhe liu
 

Roland/Brian,

Thanks for your detailed explanation and suggestions.

I am not able to re-produce the issue. One possibility could be the loose base that I have fixed (it wobbled E/W direction, not N/S direction, so when wobbling it was more like RA backlash. And we saw lots of RA spikes, no DEC spikes). Also the spikes did look like RA wobbling back and forth.

Yanzhe

On Mon, Jan 31, 2022 at 12:54 PM Brian Valente <bvalente@...> wrote:
>>> That's why I always want to see unguided data if possible.

yes agreed on that

Another possibility i've seen (not on AP mounts but others) is a bad PEC. If you see the spikes behavior during unguided you can also disable PEC during unguided capture to see if that addresses it



On Mon, Jan 31, 2022 at 12:16 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
If it's a snag it will show up during an unguided exposure as a shift rather than a spike in the guider graph. Whenever you are troubleshooting a problem, guided data is not useful because guiding tends to hide or compensate for an anomaly. That's why I always want to see unguided data if possible.

Same is true of star images that have defects. Defocus the image of the star and this can instantly tell where the problem lies, whether it's in the main optics or somewhere further down the imaging train.

Rolando

-----Original Message-----
From: Brian Valente <bvalente@...>
To: main@ap-gto.groups.io
Sent: Mon, Jan 31, 2022 1:34 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

Hi Yanzhe

I had a chance to go through your guidelog and have a few observations. I think you still need to track down the source, but we can probably rule out a few things

I don't think it's in the guiding: they happen independent of dithers and they are instantaneous, so guide pulses are causing these

I don't think it's mechanical, or at least part of the gearing: there is no clear periodicity to them, and they happen in very limited circumstances (in 6 1/2 hours of guiding i counted 6 total, all relatively close in time together)

this is the time between the spikes (in secs):
261
139
155
575
90

I did notice it only appeared to happen when the mount was pier side west, so it could be something related to shifting equipment, snags, etc.

you might try replicating that pointing position and see if it repeats in the same place @ Hour angle = -1.20 hr, Pier side = West,  Alt = 50.0 deg, Az = 151.1 deg

if it does, try disabling guiding and see if it shows up in unguided output

Also the guidelog did not include a calibration run or a guiding assistant (unguided output) so those would be helpful to include if you post a guidelog again



On Mon, Jan 31, 2022 at 11:14 AM yanzhe liu <liuyanzhe@...> wrote:
There is no backlash.
I am using OAG and it has never had any issue.


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics



--
Brian 



Brian Valente


yanzhe liu
 

Roland,

During the weekend, I noticed that if I moved RA back and force by holding scope and counter weight bar, I could hear a click sound from RA gear box, and I think there was some backlash (but barely noticeable).
I think my RA is developing backlash. Is there any instruction to remesh RA?

Thanks

Yanzhe

On Tue, Feb 1, 2022 at 9:48 AM yanzhe liu via groups.io <liuyanzhe=gmail.com@groups.io> wrote:
Roland/Brian,

Thanks for your detailed explanation and suggestions.

I am not able to re-produce the issue. One possibility could be the loose base that I have fixed (it wobbled E/W direction, not N/S direction, so when wobbling it was more like RA backlash. And we saw lots of RA spikes, no DEC spikes). Also the spikes did look like RA wobbling back and forth.

Yanzhe

On Mon, Jan 31, 2022 at 12:54 PM Brian Valente <bvalente@...> wrote:
>>> That's why I always want to see unguided data if possible.

yes agreed on that

Another possibility i've seen (not on AP mounts but others) is a bad PEC. If you see the spikes behavior during unguided you can also disable PEC during unguided capture to see if that addresses it



On Mon, Jan 31, 2022 at 12:16 PM Roland Christen via groups.io <chris1011=aol.com@groups.io> wrote:
If it's a snag it will show up during an unguided exposure as a shift rather than a spike in the guider graph. Whenever you are troubleshooting a problem, guided data is not useful because guiding tends to hide or compensate for an anomaly. That's why I always want to see unguided data if possible.

Same is true of star images that have defects. Defocus the image of the star and this can instantly tell where the problem lies, whether it's in the main optics or somewhere further down the imaging train.

Rolando

-----Original Message-----
From: Brian Valente <bvalente@...>
To: main@ap-gto.groups.io
Sent: Mon, Jan 31, 2022 1:34 pm
Subject: Re: [ap-gto] Mach1 RA guiding spike

Hi Yanzhe

I had a chance to go through your guidelog and have a few observations. I think you still need to track down the source, but we can probably rule out a few things

I don't think it's in the guiding: they happen independent of dithers and they are instantaneous, so guide pulses are causing these

I don't think it's mechanical, or at least part of the gearing: there is no clear periodicity to them, and they happen in very limited circumstances (in 6 1/2 hours of guiding i counted 6 total, all relatively close in time together)

this is the time between the spikes (in secs):
261
139
155
575
90

I did notice it only appeared to happen when the mount was pier side west, so it could be something related to shifting equipment, snags, etc.

you might try replicating that pointing position and see if it repeats in the same place @ Hour angle = -1.20 hr, Pier side = West,  Alt = 50.0 deg, Az = 151.1 deg

if it does, try disabling guiding and see if it shows up in unguided output

Also the guidelog did not include a calibration run or a guiding assistant (unguided output) so those would be helpful to include if you post a guidelog again



On Mon, Jan 31, 2022 at 11:14 AM yanzhe liu <liuyanzhe@...> wrote:
There is no backlash.
I am using OAG and it has never had any issue.


--
Brian 



Brian Valente

--
Roland Christen
Astro-Physics



--
Brian 



Brian Valente


Emilio J. Robau, P.E.
 

I am not Roland, but if you have play in either axis, you need to re-mesh the gears and adjust accordingly so the mesh is not too tight and not too loose.   I believe there is abundant details on how to do it on AP's web page in the support area.  Take a look there and you should be able to find the guidance.  Alternately after looking for the instruction documents if you still have questions, give George or Howard a call.  Hope this helps.