What are the PHD2 settings used in a Mach1?


Marcelo Figueroa
 

I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.


I'm using an 80mm refractor, f6, with the classic 50mm guide scope.


Thanks



Joel Short
 

I would suggest you use the PHD2 setup wizard which will give you a baseline for the settings and you probably won't need to change them.  Frankly, the Mach1 is so good that with an 80mm refractor you will have no trouble at all even if your guide settings aren't "perfect".  Set it and forget it.
joel


Suresh Mohan
 

I had the same doubt, couple of years back . The answer is : do a good calibration ; run guiding assistant for full 5-7 minutes , accept those settings .( before calibration you must fill the data of your guidescope / camera correctly ) 
     Then select a star at zero dec/ meridian for calibration , you r done 
Suresh


On 05-Dec-2017, at 8:56 AM, buckeyestargazer@... [ap-gto] <ap-gto@...> wrote:

 

I would suggest you use the PHD2 setup wizard which will give you a baseline for the settings and you probably won't need to change them.  Frankly, the Mach1 is so good that with an 80mm refractor you will have no trouble at all even if your guide settings aren't "perfect".  Set it and forget it.

joel


Roland Christen
 

One setting you should never use is backlash compensation. Set it off. Do all your calibration and guiding at 1x sidereal.
When you do a calibration run, set it so that it covers at least 150 arc seconds in each direction, and calibrate on a star near the celestial equator at or near the meridian. Use this setting for any object everywhere in the sky. If you always attach the camera in the same orientation then you never need to calibrate again.

Rolando



-----Original Message-----
From: marfig1970@... [ap-gto]
To: ap-gto
Sent: Mon, Dec 4, 2017 9:19 pm
Subject: [ap-gto] What are the PHD2 settings used in a Mach1?



I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.

I'm using an 80mm refractor, f6, with the classic 50mm guide scope.

Thanks




Marcelo Figueroa
 

Thanks for all the advice 

So, the other parameters (Aggressiveness, Hysteresis, etc.) simply have to be left in their default values?


Worsel
 

Use Equipment Profile Wizard to set up initial defaults.  (Connect Equipment icon-> Manage Profiles).

Do an initial calibration.

Run the Guiding Assistant (Tools -> Guiding Assistant) after your calibration.  It will provide it's best judgement on settings.  However, the default settings are a good starting point.  



Bryan


---In ap-gto@..., <marfig1970@...> wrote :

Thanks for all the advice 

So, the other parameters (Aggressiveness, Hysteresis, etc.) simply have to be left in their default values?


Michael Fulbright <mike.fulbright@...>
 

I've never using the Guiding Assistant.  Probably can't hurt but make sure you understand the settings it chooses.  DEC backlash is usually
discouraged but my mount has a bit of it that I've been too lazy to
adjust out and I find the autotuning that PHD2 does for DEC backlash
timing seems to improve guiding and recovery time from dither moves. YMMV.

I played with the Predictive PEC but as expected with a good PEM curve
it does effectively nothing and would probably just muddle things.

Key is to make sure you use the calculator provided to get the
calibration move time correct.  It just needs guide focal length and
camera pixel size (microns).

I use 0.5x for guide speed but I know 1.0x is known to work well also.

It is really hard to mess this up with a nearly perfect mount like the
Mach1 unless you overdrive the mount or set the minimum move to
something stupid small like 0.1 arcsec.

Michael Fulbright


Roland Christen
 

Don't use any hysteresis. It can cause oscillations because it is a form of over-aggressiveness.

The way to get good guiding is to do a proper accurate calibration. Then check the numbers to make sure they make sense for your focal length and pixel size.

Aggressiveness is used to slow down the amount of correction that is sent to the mount. If the software detects a +2 arc sec error and aggressiveness is set to 100%, then the mount will receive a correction signal that moves the mount - 2 arc seconds. If aggressiveness is set to 50%, then the mount receives a -1 arc sec move command.

Sometimes it is advantageous to use lower than 100% aggressiveness when the seeing is not good and the guide star is bouncing around. I like to use 3 to 5 second guide exposures at 80% aggressiveness and a Min Move of .15 arc sec (.01 sec min move at 1x sidereal) and a 7.5 arc sec max move (.5 sec max move at 1x sidereal).

Rolando



-----Original Message-----
From: marfig1970@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 1:35 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Thanks for all the advice 

So, the other parameters (Aggressiveness, Hysteresis, etc.) simply have to be left in their default values?



Roland Christen
 


I use 0.5x for guide speed but I know 1.0x is known to work well also.
If you use .5x for guiding, then indeed you may have to add some Dec backlash because your reversal time is essentially doubled, and the effect of any backlash is basically doubled. Dec backlash setting other than zero is a potential source of oscillation, that is why i do not recommend using any. Rather than guiding at .5x, use 1x guiding to minimize Dec reversal time, and this will speed up your dither recovery time. The 1 X guide rate is very accurate and the mount will respond better at the sub-arc sec level.

The slower rates were included from the very first mounts we made for manual guiding with a cross-hair eyepiece. It was done because human eye-hand response delay is on the order of 1/2 to 1 second, and at the 1x rate would cause the guide star to move too far. However, modern electronics does not have such delay, and the mount can respond to millisecond move commands, unlike a human guider.


-----Original Message-----
From: Michael Fulbright mike.fulbright@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 2:06 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?

I've never using the Guiding Assistant.  Probably can't hurt but make
sure you understand the settings it chooses.  DEC backlash is usually
discouraged but my mount has a bit of it that I've been too lazy to
adjust out and I find the autotuning that PHD2 does for DEC backlash
timing seems to improve guiding and recovery time from dither moves. YMMV.

I played with the Predictive PEC but as expected with a good PEM curve
it does effectively nothing and would probably just muddle things.

Key is to make sure you use the calculator provided to get the
calibration move time correct.  It just needs guide focal length and
camera pixel size (microns).

I use 0.5x for guide speed but I know 1.0x is known to work well also.

It is really hard to mess this up with a nearly perfect mount like the
Mach1 unless you overdrive the mount or set the minimum move to
something stupid small like 0.1 arcsec.

Michael Fulbright


------------------------------------
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Michael Fulbright <mike.fulbright@...>
 

Thanks for the suggestion I can give it a try next clear night.   I think I've played with both 0.5x and 1.0x over time and being predominately seeing limited (Mid-Atlantic can be cruel seeing-wise) I'd just settled on whatever I tried last!

Michael Fulbright

On 12/5/2017 3:34 PM, chris1011@... [ap-gto] wrote:
 


I use 0.5x for guide speed but I know 1.0x is known to work well also.
If you use .5x for guiding, then indeed you may have to add some Dec backlash because your reversal time is essentially doubled, and the effect of any backlash is basically doubled. Dec backlash setting other than zero is a potential source of oscillation, that is why i do not recommend using any. Rather than guiding at .5x, use 1x guiding to minimize Dec reversal time, and this will speed up your dither recovery time. The 1 X guide rate is very accurate and the mount will respond better at the sub-arc sec level.

The slower rates were included from the very first mounts we made for manual guiding with a cross-hair eyepiece. It was done because human eye-hand response delay is on the order of 1/2 to 1 second, and at the 1x rate would cause the guide star to move too far. However, modern electronics does not have such delay, and the mount can respond to millisecond move commands, unlike a human guider.


-----Original Message-----
From: Michael Fulbright mike.fulbright@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 2:06 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?

I've never using the Guiding Assistant.  Probably can't hurt but make
sure you understand the settings it chooses.  DEC backlash is usually
discouraged but my mount has a bit of it that I've been too lazy to
adjust out and I find the autotuning that PHD2 does for DEC backlash
timing seems to improve guiding and recovery time from dither moves. YMMV.

I played with the Predictive PEC but as expected with a good PEM curve
it does effectively nothing and would probably just muddle things.

Key is to make sure you use the calculator provided to get the
calibration move time correct.  It just needs guide focal length and
camera pixel size (microns).

I use 0.5x for guide speed but I know 1.0x is known to work well also.

It is really hard to mess this up with a nearly perfect mount like the
Mach1 unless you overdrive the mount or set the minimum move to
something stupid small like 0.1 arcsec.

Michael Fulbright


------------------------------------
Posted by: Michael Fulbright <mike.fulbright@...>
------------------------------------

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Zac Kruger <z@...>
 

Roland,

Have you successfully used PHD to attempt calibration over the recommended 150 arc sec?  Using an OAG at 714mm FL and 3.8u pixel size I have been entirely unsuccessful because of what I assume is due to the way PHD functions.  It loses track of the star when using such large calibration steps.  I have to be somewhere at 150-250ms pulses in order to calibrate at all.  Doing that to cover 150'' would require an immensely long calibration time.

--Zac

On Tue, Dec 5, 2017 at 9:01 AM, chris1011@... [ap-gto] <ap-gto@...> wrote:
 

One setting you should never use is backlash compensation. Set it off. Do all your calibration and guiding at 1x sidereal.
When you do a calibration run, set it so that it covers at least 150 arc seconds in each direction, and calibrate on a star near the celestial equator at or near the meridian. Use this setting for any object everywhere in the sky. If you always attach the camera in the same orientation then you never need to calibrate again.

Rolando




-----Original Message-----
From: marfig1970@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Mon, Dec 4, 2017 9:19 pm
Subject: [ap-gto] What are the PHD2 settings used in a Mach1?



I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.

I'm using an 80mm refractor, f6, with the classic 50mm guide scope.

Thanks





Roland Christen
 

Don't play with guide speed. Leave it sit at 1x and play with the other variables. Min Move is important - don't set it too high or you get no corrections. And try not to use any backlash comp or hysteresis. These will just complicate things and may cause instability, overshoot, oscillations, etc.

Rolando



-----Original Message-----
From: Michael Fulbright mike.fulbright@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 2:40 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Thanks for the suggestion I can give it a try next clear night.   I think I've played with both 0.5x and 1.0x over time and being predominately seeing limited (Mid-Atlantic can be cruel seeing-wise) I'd just settled on whatever I tried last!

Michael Fulbright

On 12/5/2017 3:34 PM, chris1011@... [ap-gto] wrote:
 

I use 0.5x for guide speed but I know 1.0x is known to work well also.
If you use .5x for guiding, then indeed you may have to add some Dec backlash because your reversal time is essentially doubled, and the effect of any backlash is basically doubled. Dec backlash setting other than zero is a potential source of oscillation, that is why i do not recommend using any. Rather than guiding at .5x, use 1x guiding to minimize Dec reversal time, and this will speed up your dither recovery time. The 1 X guide rate is very accurate and the mount will respond better at the sub-arc sec level.

The slower rates were included from the very first mounts we made for manual guiding with a cross-hair eyepiece. It was done because human eye-hand response delay is on the order of 1/2 to 1 second, and at the 1x rate would cause the guide star to move too far. However, modern electronics does not have such delay, and the mount can respond to millisecond move commands, unlike a human guider.


-----Original Message-----
From: Michael Fulbright mike.fulbright@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 2:06 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?

I've never using the Guiding Assistant.  Probably can't hurt but make
sure you understand the settings it chooses.  DEC backlash is usually
discouraged but my mount has a bit of it that I've been too lazy to
adjust out and I find the autotuning that PHD2 does for DEC backlash
timing seems to improve guiding and recovery time from dither moves. YMMV.

I played with the Predictive PEC but as expected with a good PEM curve
it does effectively nothing and would probably just muddle things.

Key is to make sure you use the calculator provided to get the
calibration move time correct.  It just needs guide focal length and
camera pixel size (microns).

I use 0.5x for guide speed but I know 1.0x is known to work well also.

It is really hard to mess this up with a nearly perfect mount like the
Mach1 unless you overdrive the mount or set the minimum move to
something stupid small like 0.1 arcsec.

Michael Fulbright


------------------------------------
Posted by: Michael Fulbright <mike.fulbright@...>
------------------------------------

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Worsel
 

Michael

Maybe its understood, but don't confuse "Use backlash comp" (checkbox on Algorithm tab under Brain) with "Use Declination comp" (checkbox on Guiding tab under Brain).  The latter adjusts the guiding for the declination of the imaged object and is useful enhancement on most mounts with ASCOM enabled.

Bryan


---In ap-gto@..., <chris1011@...> wrote :

Don't play with guide speed. Leave it sit at 1x and play with the other variables. Min Move is important - don't set it too high or you get no corrections. And try not to use any backlash comp or hysteresis. These will just complicate things and may cause instability, overshoot, oscillations, etc.

Rolando



-----Original Message-----
From: Michael Fulbright mike.fulbright@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Tue, Dec 5, 2017 2:40 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Thanks for the suggestion I can give it a try next clear night.   I think I've played with both 0.5x and 1.0x over time and being predominately seeing limited (Mid-Atlantic can be cruel seeing-wise) I'd just settled on whatever I tried last!

Michael Fulbright


Joe Zeglinski
 

Huh ???
     Brian – if the “algorithm” has been set to “NOT use backlash compensation”, then doesn’t that take precedence over the Guiding tab option of “Use DEC comp” ? It may have been an unfortunate duplication of terms – maybe the latter actually first,  “re-enables” compensation again in the algorithm . Would have to, right?
 
Joe
 

From: bryancashion@... [ap-gto]
Sent: Tuesday, December 5, 2017 4:20 PM
To: ap-gto@...
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?
 


Michael
 
Maybe its understood, but don't confuse "Use backlash comp" (checkbox on Algorithm tab under Brain) with "Use Declination comp" (checkbox on Guiding tab under Brain).  The latter adjusts the guiding for the declination of the imaged object and is useful enhancement on most mounts with ASCOM enabled.
 
Bryan

 


Worsel
 

Joe

The two do completely different actions.

From documentation

'Use Declination Compensation' - if PHD2 can get pointing information from the mount via an ASCOM connection ('Mount' or 'Aux'), it will automatically adjust the RA guide rate based on the current declination.  This box should normally be left checked except in unusual cases.  For example, SiTech mount controllers evidently apply a compensation automatically, in which case the box should be left un-checked.  Don't confuse this option with 'Declination backlash compensation', which is an entirely different feature.'Use Declination Compensation' - if PHD2 can get pointing information from the mount via an ASCOM connection ('Mount' or 'Aux'), it will automatically adjust the RA guide rate based on the current declination.  This box should normally be left checked except in unusual cases.  For example, SiTech mount controllers evidently apply a compensation automatically, in which case the box should be left un-checked.  Don't confuse this option with 'Declination backlash compensation', which is an entirely different feature.



 

'Use backlash comp' - this controls whether PHD2 will apply a compensation factor when the direction of declination guiding needs to be reversed.  Measurement of backlash and calculation of a good starting value for the compensation factor is done in the Guiding Assistant.  The size of the additional guide correction (compensation value) is shown in the 'Amount' field adjacent to the checkbox.  This amount may be adjusted upward or downward by PHD2 if necessary to tune the guiding results.  In either case, the adjustments are made conservatively in order to avoid making guiding unstable.  Since PHD2 has the ability to detect and adapt to over-corrections, the backlash compensation available here should work better than the fixed backlash compensation available in many mount controllers.  If you use the PHD2 backlash compensation, you should disable any  backlash compensation in the mount.  

 


Bryan




---In ap-gto@..., <J.Zeglinski@...> wrote :

Huh ???
     Brian – if the “algorithm” has been set to “NOT use backlash compensation”, then doesn’t that take precedence over the Guiding tab option of “Use DEC comp” ? It may have been an unfortunate duplication of terms – maybe the latter actually first,  “re-enables” compensation again in the algorithm . Would have to, right?
 
Joe

 


Worsel
 

Roland

Which algorithm(s) do you recommend, if not hysteresis?

Bryan


---In ap-gto@..., <chris1011@...> wrote :

Don't use any hysteresis. It can cause oscillations because it is a form of over-aggressiveness.

The way to get good guiding is to do a proper accurate calibration. Then check the numbers to make sure they make sense for your focal length and pixel size.

Aggressiveness is used to slow down the amount of correction that is sent to the mount. If the software detects a +2 arc sec error and aggressiveness is set to 100%, then the mount will receive a correction signal that moves the mount - 2 arc seconds. If aggressiveness is set to 50%, then the mount receives a -1 arc sec move command.

Sometimes it is advantageous to use lower than 100% aggressiveness when the seeing is not good and the guide star is bouncing around. I like to use 3 to 5 second guide exposures at 80% aggressiveness and a Min Move of .15 arc sec (.01 sec min move at 1x sidereal) and a 7.5 arc sec max move (.5 sec max move at 1x sidereal).

Rolando



Roland Christen
 

The total distance traveled should be on the order of 150 arc sec. That is equivalent to 10 seconds of move command at 1x in any other guide software and would move the star enough to accurately calculate the pixel/sec move parameter. A total of 10 seconds move command is normal in MaximDL and is done in one step in that program. In your example of 714mm, 3.8 micron pixel size, you are running at 1.1 arc sec per pixel. The resultant pixel/sec parameter would be 13.7 pixels per second at 1x sidereal.

The reason for the 10 second cal run in MaximDL is to minimize the delay error in reversing Dec. If it takes 1 second to reverse Dec, then the parameter would be in error by 10%, which is not a big problem. If the cal run was only for 3 seconds, then the resultant error is 33%, which is quite large, and any setting of aggressiveness above 70% will begin to cause oscillations because the loop gain is now above 100%.

It may be that PHD can compensate for this reversal delay in Dec by doing calibration only in one direction. I'm not familiar with the workings of the software, I only know how it was done in all the other programs.

Rolando



-----Original Message-----
From: Zac Kruger z@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 4:04 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Roland,

Have you successfully used PHD to attempt calibration over the recommended 150 arc sec?  Using an OAG at 714mm FL and 3.8u pixel size I have been entirely unsuccessful because of what I assume is due to the way PHD functions.  It loses track of the star when using such large calibration steps.  I have to be somewhere at 150-250ms pulses in order to calibrate at all.  Doing that to cover 150'' would require an immensely long calibration time.

--Zac

On Tue, Dec 5, 2017 at 9:01 AM, chris1011@... [ap-gto] <ap-gto@...> wrote:
 
One setting you should never use is backlash compensation. Set it off. Do all your calibration and guiding at 1x sidereal.
When you do a calibration run, set it so that it covers at least 150 arc seconds in each direction, and calibrate on a star near the celestial equator at or near the meridian. Use this setting for any object everywhere in the sky. If you always attach the camera in the same orientation then you never need to calibrate again.

Rolando



-----Original Message-----
From: marfig1970@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Mon, Dec 4, 2017 9:19 pm
Subject: [ap-gto] What are the PHD2 settings used in a Mach1?



I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.

I'm using an 80mm refractor, f6, with the classic 50mm guide scope.

Thanks







topboxman
 

PHD2 is a totally different animal than other guiding software like Maxim DL and the names (i.e. calibration steps) and parameters are not likely going to agree or match.

PHD2 has a cool "Calibration Step Calculator" to calculate for the best Calibration step size in milliseconds based on declination of guide star, focal length of guide scope, pixel size of guide camera and mount's guide speed. Use this instead of guessing and will NOT agree with Maxim auto guiding parameters.

Click on the "Brain" icon, click on "Guiding" tab and finally click on "Calculate" button and it will pop up a window for you to fill in the blanks.

Peter


---In ap-gto@..., <chris1011@...> wrote :

The total distance traveled should be on the order of 150 arc sec. That is equivalent to 10 seconds of move command at 1x in any other guide software and would move the star enough to accurately calculate the pixel/sec move parameter. A total of 10 seconds move command is normal in MaximDL and is done in one step in that program. In your example of 714mm, 3.8 micron pixel size, you are running at 1.1 arc sec per pixel. The resultant pixel/sec parameter would be 13.7 pixels per second at 1x sidereal.

The reason for the 10 second cal run in MaximDL is to minimize the delay error in reversing Dec. If it takes 1 second to reverse Dec, then the parameter would be in error by 10%, which is not a big problem. If the cal run was only for 3 seconds, then the resultant error is 33%, which is quite large, and any setting of aggressiveness above 70% will begin to cause oscillations because the loop gain is now above 100%.

It may be that PHD can compensate for this reversal delay in Dec by doing calibration only in one direction. I'm not familiar with the workings of the software, I only know how it was done in all the other programs.

Rolando



-----Original Message-----
From: Zac Kruger z@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Tue, Dec 5, 2017 4:04 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Roland,

Have you successfully used PHD to attempt calibration over the recommended 150 arc sec?  Using an OAG at 714mm FL and 3.8u pixel size I have been entirely unsuccessful because of what I assume is due to the way PHD functions.  It loses track of the star when using such large calibration steps.  I have to be somewhere at 150-250ms pulses in order to calibrate at all.  Doing that to cover 150'' would require an immensely long calibration time.

--Zac

On Tue, Dec 5, 2017 at 9:01 AM, chris1011@... [ap-gto] <ap-gto@...> wrote:
 
One setting you should never use is backlash compensation. Set it off. Do all your calibration and guiding at 1x sidereal.
When you do a calibration run, set it so that it covers at least 150 arc seconds in each direction, and calibrate on a star near the celestial equator at or near the meridian. Use this setting for any object everywhere in the sky. If you always attach the camera in the same orientation then you never need to calibrate again.

Rolando



-----Original Message-----
From: marfig1970@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Mon, Dec 4, 2017 9:19 pm
Subject: [ap-gto] What are the PHD2 settings used in a Mach1?



I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.

I'm using an 80mm refractor, f6, with the classic 50mm guide scope.

Thanks







Roland Christen
 

Yes I know it's different, but you still have to move the scope a certain distance in Dec in order to get proper values for the program. We have dealt with several customers now who did not understand what calibration does and ended up with bogus results. The guiding was totally off because the mount was being yanked back and forth with oversize error signals. Anyhow, the mount will do as you ask, no more no less.

Rolando



-----Original Message-----
From: pnagy@... [ap-gto]
To: ap-gto
Sent: Tue, Dec 5, 2017 5:02 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



PHD2 is a totally different animal than other guiding software like Maxim DL and the names (i.e. calibration steps) and parameters are not likely going to agree or match.

PHD2 has a cool "Calibration Step Calculator" to calculate for the best Calibration step size in milliseconds based on declination of guide star, focal length of guide scope, pixel size of guide camera and mount's guide speed. Use this instead of guessing and will NOT agree with Maxim auto guiding parameters.

Click on the "Brain" icon, click on "Guiding" tab and finally click on "Calculate" button and it will pop up a window for you to fill in the blanks.

Peter


---In ap-gto@..., wrote :

The total distance traveled should be on the order of 150 arc sec. That is equivalent to 10 seconds of move command at 1x in any other guide software and would move the star enough to accurately calculate the pixel/sec move parameter. A total of 10 seconds move command is normal in MaximDL and is done in one step in that program. In your example of 714mm, 3.8 micron pixel size, you are running at 1.1 arc sec per pixel. The resultant pixel/sec parameter would be 13.7 pixels per second at 1x sidereal.

The reason for the 10 second cal run in MaximDL is to minimize the delay error in reversing Dec. If it takes 1 second to reverse Dec, then the parameter would be in error by 10%, which is not a big problem. If the cal run was only for 3 seconds, then the resultant error is 33%, which is quite large, and any setting of aggressiveness above 70% will begin to cause oscillations because the loop gain is now above 100%.

It may be that PHD can compensate for this reversal delay in Dec by doing calibration only in one direction. I'm not familiar with the workings of the software, I only know how it was done in all the other programs.

Rolando



-----Original Message-----
From: Zac Kruger z@... [ap-gto] gto@...>
To: ap-gto gto@...>
Sent: Tue, Dec 5, 2017 4:04 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Roland,

Have you successfully used PHD to attempt calibration over the recommended 150 arc sec?  Using an OAG at 714mm FL and 3.8u pixel size I have been entirely unsuccessful because of what I assume is due to the way PHD functions.  It loses track of the star when using such large calibration steps.  I have to be somewhere at 150-250ms pulses in order to calibrate at all.  Doing that to cover 150'' would require an immensely long calibration time.

--Zac

On Tue, Dec 5, 2017 at 9:01 AM, chris1011@... [ap-gto] <ap-gto@...> wrote:
 
One setting you should never use is backlash compensation. Set it off. Do all your calibration and guiding at 1x sidereal.
When you do a calibration run, set it so that it covers at least 150 arc seconds in each direction, and calibrate on a star near the celestial equator at or near the meridian. Use this setting for any object everywhere in the sky. If you always attach the camera in the same orientation then you never need to calibrate again.

Rolando



-----Original Message-----
From: marfig1970@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Mon, Dec 4, 2017 9:19 pm
Subject: [ap-gto] What are the PHD2 settings used in a Mach1?



I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.

I'm using an 80mm refractor, f6, with the classic 50mm guide scope.

Thanks









topboxman
 

Hi Rolando,

This is what PHD2 "Calibration Step Calculator"is for. No more guessing for calibration step size and it's pretty accurate. Never had an issue with this using my A-P1100GTO mount. The calculator takes into account of Declination of guide star as well as other parameters so that proper calibration step size will be calculated correctly.

Peter


---In ap-gto@..., <chris1011@...> wrote :

Yes I know it's different, but you still have to move the scope a certain distance in Dec in order to get proper values for the program. We have dealt with several customers now who did not understand what calibration does and ended up with bogus results. The guiding was totally off because the mount was being yanked back and forth with oversize error signals. Anyhow, the mount will do as you ask, no more no less.

Rolando



-----Original Message-----
From: pnagy@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Tue, Dec 5, 2017 5:02 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



PHD2 is a totally different animal than other guiding software like Maxim DL and the names (i.e. calibration steps) and parameters are not likely going to agree or match.

PHD2 has a cool "Calibration Step Calculator" to calculate for the best Calibration step size in milliseconds based on declination of guide star, focal length of guide scope, pixel size of guide camera and mount's guide speed. Use this instead of guessing and will NOT agree with Maxim auto guiding parameters.

Click on the "Brain" icon, click on "Guiding" tab and finally click on "Calculate" button and it will pop up a window for you to fill in the blanks.

Peter


---In ap-gto@..., <chris1011@...> wrote :

The total distance traveled should be on the order of 150 arc sec. That is equivalent to 10 seconds of move command at 1x in any other guide software and would move the star enough to accurately calculate the pixel/sec move parameter. A total of 10 seconds move command is normal in MaximDL and is done in one step in that program. In your example of 714mm, 3.8 micron pixel size, you are running at 1.1 arc sec per pixel. The resultant pixel/sec parameter would be 13.7 pixels per second at 1x sidereal.

The reason for the 10 second cal run in MaximDL is to minimize the delay error in reversing Dec. If it takes 1 second to reverse Dec, then the parameter would be in error by 10%, which is not a big problem. If the cal run was only for 3 seconds, then the resultant error is 33%, which is quite large, and any setting of aggressiveness above 70% will begin to cause oscillations because the loop gain is now above 100%.

It may be that PHD can compensate for this reversal delay in Dec by doing calibration only in one direction. I'm not familiar with the workings of the software, I only know how it was done in all the other programs.

Rolando



-----Original Message-----
From: Zac Kruger z@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Tue, Dec 5, 2017 4:04 pm
Subject: Re: [ap-gto] What are the PHD2 settings used in a Mach1?



Roland,

Have you successfully used PHD to attempt calibration over the recommended 150 arc sec?  Using an OAG at 714mm FL and 3.8u pixel size I have been entirely unsuccessful because of what I assume is due to the way PHD functions.  It loses track of the star when using such large calibration steps.  I have to be somewhere at 150-250ms pulses in order to calibrate at all.  Doing that to cover 150'' would require an immensely long calibration time.

--Zac

On Tue, Dec 5, 2017 at 9:01 AM, chris1011@... [ap-gto] <ap-gto@...> wrote:
 
One setting you should never use is backlash compensation. Set it off. Do all your calibration and guiding at 1x sidereal.
When you do a calibration run, set it so that it covers at least 150 arc seconds in each direction, and calibrate on a star near the celestial equator at or near the meridian. Use this setting for any object everywhere in the sky. If you always attach the camera in the same orientation then you never need to calibrate again.

Rolando



-----Original Message-----
From: marfig1970@... [ap-gto] <ap-gto@...>
To: ap-gto <ap-gto@...>
Sent: Mon, Dec 4, 2017 9:19 pm
Subject: [ap-gto] What are the PHD2 settings used in a Mach1?



I'm a new user of Mach1, fantastic machine by the way, and I'm curious about which are the best settings in PHD2.

I'm using an 80mm refractor, f6, with the classic 50mm guide scope.

Thanks