Date   

Re: AP900 DEC sawtooth guiding

Steve Reilly
 

If he doesn’t have the hand controller the driver, I would think, should show the setting for sure.

 

Steve

 

From: ap-gto@... [mailto:ap-gto@...]
Sent: Thursday, September 22, 2016 11:21 PM
To: ap-gto@...
Subject: Re: [ap-gto] Re: AP900 DEC sawtooth guiding

 

 

The log shows the calibration was near-perfect.  PHD2 does a bunch of sanity-checks on calibration and generates alerts when things don't look right - none of that happened.   I suspect there's a non-zero Dec backlash compensation setting in the mount, and that's what needs to be dealt with next.  Since this is a second-hand mount, Anis doesn't have any way to know what might have been programmed by the original owner.

Cheers,
Bruce


Re: Park position

Worsel
 

Thanks very much!


Bryan


Re: Park position

Worsel
 

Suresh

I use Astrotortilla to plate solve.  It shows the RA/Dec of the center of the test image, the FOV of the image and the rotation of the image.  


Bryan


Re: Park position

bw
 

Hi Suresh.  One of the computed values in any plate-solve is "position angle", which determines the angular position of the camera relative to the stars.  As long as you have a reference image showing the dark nebula relative to the field stars, you'll know how it's going to be oriented.

Have fun,
Bruce


Re: AP900 DEC sawtooth guiding

bw
 

The log shows the calibration was near-perfect.  PHD2 does a bunch of sanity-checks on calibration and generates alerts when things don't look right - none of that happened.   I suspect there's a non-zero Dec backlash compensation setting in the mount, and that's what needs to be dealt with next.  Since this is a second-hand mount, Anis doesn't have any way to know what might have been programmed by the original owner.

Cheers,
Bruce


Re: Park position

Roland Christen
 

Someone else will have to come in on this question. I cannot answer it adequately, sorry.
 
Rolando
 
 

-----Original Message-----
From: Suresh Mohan Neelmegh drsureshmohan@... [ap-gto]
To: ap-gto
Sent: Thu, Sep 22, 2016 8:45 pm
Subject: Re: [ap-gto] Park position



Thanks Rolando, may i ask you a question about TSX ? lets say i wish to shoot LBN 777. My set up is a takahashi fsq 85/Mach1 /canon 600 D. You know very well that there will be no data in a 20 minute sub except the stars , Suppose i want the  dark nebula in a certain orientation is there a way i can do that using image link?(just using a test shot of the region ). In other words my question is does plate solve tell you the orientation of the stars to your camera
Thanks
Suresh
Suresh

On Fri, Sep 23, 2016 at 12:25 AM, bryancashion@... [ap-gto] <ap-gto@...> wrote:
 
Using the latest ASCOM driver (not APCC), is Park at "Current Position" equivalent to Park 0?

Bryan


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

With Park 0, you can park the scope anywhere in the sky. The mount will simply stop moving, motors de-energized. Then turn off power. Assuming that you don't tear down the scope and mount, but leave it set up, with Autoconnect = YES, you can simply switch on power next night and go to any object. The mount will go there accurately.
 
Rolando
 





Re: AP900 DEC sawtooth guiding

Anis Mo
 

Thanks Rolando! I think I am getting a sense of things to check on now.

I have a bunch of stuff to check with guiding parameters (Bruce also pointed to me few things to work on). I will get this done the next chance I get (probably next week) and hopefully have better results.


Re: Guiding Issues

Stuart
 

Antoine, thanks for that note. I wonder then if all that really matters is that you have the box checked for the camera doing the guiding. Checking both maybe doesn't hurt but you must have it checked for the device assigned as "autoguider".

My memory of the problem I had with TSX and my AP900GTO is fuzzy. I had a strange thing happen when reconnecting my STL11000 after service. TSX lost all of my preset parameters. Then the '-' sign went missing on my timezone offset which put me in India. Weirdly close to Lucknow India as it happens. Guess where I live. Lucknow ONTARIO CANADA. OMG - what a confusing thing to happen. So, part of my problem was the checkbox got unchecked on the autoguider tab but also TSX thought I was in India according to the timezone offset but for some reason it is happy to accept your RA and Dec so it displayed the local sky correctly for the time of day.

Stuart

On Thu, Sep 22, 2016 at 6:19 PM, antoine.pavlin@... [ap-gto] <ap-gto@...> wrote:
 

I use TSX with Camera Add-On to image with my Mach1GTO.

I have « Auto Reverse X on G » checked on both Camera Setup and Autoguide Setup. This allows TSX to automatically reverse autoguide RA corrections after a meridian flip.

I quote Daniel Bisque :
« Daniel R. Bisque:
• By default, the Auto-Reverse X for GEMs checkbox is turned on for both the Imager and the Guider.  When the Auto-Reverse X for GEMs checkbox is turned on, TheSkyX automatically reverses the X direction during guiding based on the OTA side of the pier and the original calibration.
• If the Auto-Reverse X for GEMs checkbox is turned off, TheSkyX no longer automatically reverses the X direction; this responsibility is left to the user.  Turn on the Reverse X checkbox to do so when necessary.
Best practice: turn on the Auto-Reverse X for GEMs checkbox.
There are two checkboxes because you can choose to image or autoguide using any of the sensors attached to Camera or Autoguider.

Clear skies

Antoine

De : Stuart Heggie stuart.j.heggie@... [ap-gto]

---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus

[Non-text portions of this message have been removed]





Re: Park position

Suresh Mohan
 

Thanks Rolando, may i ask you a question about TSX ? lets say i wish to shoot LBN 777. My set up is a takahashi fsq 85/Mach1 /canon 600 D. You know very well that there will be no data in a 20 minute sub except the stars , Suppose i want the  dark nebula in a certain orientation is there a way i can do that using image link?(just using a test shot of the region ). In other words my question is does plate solve tell you the orientation of the stars to your camera
Thanks
Suresh
Suresh

On Fri, Sep 23, 2016 at 12:25 AM, bryancashion@... [ap-gto] <ap-gto@...> wrote:
 

Using the latest ASCOM driver (not APCC), is Park at "Current Position" equivalent to Park 0?


Bryan


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

With Park 0, you can park the scope anywhere in the sky. The mount will simply stop moving, motors de-energized. Then turn off power. Assuming that you don't tear down the scope and mount, but leave it set up, with Autoconnect = YES, you can simply switch on power next night and go to any object. The mount will go there accurately.
 
Rolando
 



Re: AP900 DEC sawtooth guiding

Roland Christen
 

That kind of sawtooth guiding is very indicative of loop gain greater than 100% due to faulty calibration parameters. It says something like "send a 2 arc second correction for a 1 arc second error". It's called overcorrection or Loop Gain > 100%, etc. The software is misinterpreting the actual error and sending a very much larger correction signal to the mount. I'm guessing at least a 200% overcorrection, possibly due to interpreting a wrong binning setting or a wrong calibration parameter.
 
Not being familiar with PHD, I cannot begin to guess where the error might be. In Maxim, it is easy to see the actual calibration numbers, and you can even modify them to the correct value for 100% stable operation.
 
It's almost like the software is interpreting the smaller RA parameter number to be applied to the Dec axis. That is the danger of calibrating away from the celestial equator where the two numbers (RA and Dec) would be the same. If they are not the same, then you know right away that your calibration was not accurate.
 
Rolando
 
 

-----Original Message-----
From: anismo@... [ap-gto]
To: ap-gto
Sent: Thu, Sep 22, 2016 2:59 pm
Subject: Re: [ap-gto] Re: AP900 DEC sawtooth guiding



Additional info: Instead of the PHD log, I have it loaded in PHDLab

Here is a 13.5 minute with normal guiding: http://dev1.codelathe.com/url/zlk2xugsghth
Here is the case showing the "sawtooth": http://dev1.codelathe.com/url/y3twje1dnr2i
 



Re: Park position

Roland Christen
 

Park 0 is a keypad designation for Current position. Same as Current position in the Ascom Driver.
 
Rolando
 
 

-----Original Message-----
From: bryancashion@... [ap-gto]
To: ap-gto
Sent: Thu, Sep 22, 2016 1:55 pm
Subject: Re: [ap-gto] Park position



Using the latest ASCOM driver (not APCC), is Park at "Current Position" equivalent to Park 0?

Bryan


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

With Park 0, you can park the scope anywhere in the sky. The mount will simply stop moving, motors de-energized. Then turn off power. Assuming that you don't tear down the scope and mount, but leave it set up, with Autoconnect = YES, you can simply switch on power next night and go to any object. The mount will go there accurately.
 
Rolando
 




Re: Guiding Issues

Antoine PAVLIN
 

I use TSX with Camera Add-On to image with my Mach1GTO.

I have « Auto Reverse X on G » checked on both Camera Setup and Autoguide Setup. This allows TSX to automatically reverse autoguide RA corrections after a meridian flip.

I quote Daniel Bisque :
« Daniel R. Bisque:
• By default, the Auto-Reverse X for GEMs checkbox is turned on for both the Imager and the Guider.  When the Auto-Reverse X for GEMs checkbox is turned on, TheSkyX automatically reverses the X direction during guiding based on the OTA side of the pier and the original calibration.
• If the Auto-Reverse X for GEMs checkbox is turned off, TheSkyX no longer automatically reverses the X direction; this responsibility is left to the user.  Turn on the Reverse X checkbox to do so when necessary.
Best practice: turn on the Auto-Reverse X for GEMs checkbox.
There are two checkboxes because you can choose to image or autoguide using any of the sensors attached to Camera or Autoguider.

Clear skies

Antoine



De : Stuart Heggie stuart.j.heggie@... [ap-gto]

---
L'absence de virus dans ce courrier électronique a été vérifiée par le logiciel antivirus Avast.
https://www.avast.com/antivirus


[Non-text portions of this message have been removed]


Re: AP900 DEC sawtooth guiding

Anis Mo
 

Additional info: Instead of the PHD log, I have it loaded in PHDLab

Here is a 13.5 minute with normal guiding: http://dev1.codelathe.com/url/zlk2xugsghth
Here is the case showing the "sawtooth": http://dev1.codelathe.com/url/y3twje1dnr2i
 


Re: AP900 DEC sawtooth guiding

Anis Mo
 

Thanks Bruce, That is a good point. I wasn't sure if this is a mount related issue vs PHD2 issue. I guess the fact that the normal guiding working probably indicates something settings related. I am also planning to run  the pulse guide test tonight as well and see if I can get some additional details.


Re: AP900 DEC sawtooth guiding

bw
 

Hi Anis.  I think you're posting to the wrong forum, the folks here aren't very familiar with PHD2.  If you post your question over here: Google Groups

 



and include your guide log, we'll probably be able to sort out your problem.  In the meantime, get on the latest release of PHD2 and read the help file regarding the Guiding Assistant and how to measure your Dec backlash.

Good luck,
Bruce W.


Re: Park position

Worsel
 

Using the latest ASCOM driver (not APCC), is Park at "Current Position" equivalent to Park 0?

Bryan


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

With Park 0, you can park the scope anywhere in the sky. The mount will simply stop moving, motors de-energized. Then turn off power. Assuming that you don't tear down the scope and mount, but leave it set up, with Autoconnect = YES, you can simply switch on power next night and go to any object. The mount will go there accurately.
 
Rolando
 


Re: AP900 DEC sawtooth guiding

Anis Mo
 

Hi Rolando

Appreciate your help! 

Here are some data I pulled from the log after calibration

============================
Calibration Begins at 2016-09-21 21:49:01
Equipment Profile = AP900_LODESTARX2
Camera = Starlight Xpress Lodestar Guider (ASCOM)
Exposure = 8000 ms
Pixel scale = 4.60 arc-sec/px, Binning = 1, Focal length = 386 mm
Mount = AstroPhysicsV2, Calibration Step = 1200 ms, Assume orthogonal axes = no
Dec = 58.5 deg, Hour angle = -5.14 hr, Pier side = West, Rotator pos = N/A
Lock position = 56.602, 134.484, Star position = 56.602, 134.484, HFD = 3.36 px

West calibration complete. Angle = -137.3 deg, Rate = 1.817 px/sec
North calibration complete. Angle = 132.7 deg, Rate = 3.438 px/sec

================================

Guiding Begins at 2016-09-21 22:00:34
Dither = both axes, Dither scale = 1.000, Image noise reduction = none, Guide-frame time lapse = 0, Server enabled
Pixel scale = 4.60 arc-sec/px, Binning = 1, Focal length = 386 mm
Search region = 15 px, Star mass tolerance = 50.0%
Equipment Profile = AP900_LODESTARX2
Camera = Starlight Xpress Lodestar Guider (ASCOM), gain = 95, full size = 752 x 580, no dark, no defect map, pixel size = 8.6 um
Exposure = 10000 ms
Mount = AstroPhysicsV2,  connected, guiding enabled, xAngle = -137.3, xRate = 1.817, yAngle = -227.3, yRate = 3.438
X guide algorithm = Hysteresis, Hysteresis = 0.100, Aggression = 0.100, Minimum move = 0.200
Y guide algorithm = Hysteresis, Hysteresis = 0.100, Aggression = 0.050, Minimum move = 0.200
Backlash comp = disabled, pulse = 0 ms
Calibration step = phdlab_placeholder, Max RA duration = 2500, Max DEC duration = 2500, DEC guide mode = Auto


RA Guide Speed = 15.0 a-s/s, Dec Guide Speed = 15.0 a-s/s, Cal Dec = 58.5, Last Cal Issue = None, Timestamp = 9/21/2016 9:54:46 PM
Dec = 58.5 deg, Hour angle = -4.95 hr, Pier side = West, Rotator pos = N/A



==============================

I have the whole PHD2 log (I did multiple calibration as well as guide/dither with different settings) if that will be useful






Regards
Anis








Re: Park position

Roland Christen
 

With Park 0, you can park the scope anywhere in the sky. The mount will simply stop moving, motors de-energized. Then turn off power. Assuming that you don't tear down the scope and mount, but leave it set up, with Autoconnect = YES, you can simply switch on power next night and go to any object. The mount will go there accurately.
 
Rolando
 
 

-----Original Message-----
From: Suresh Mohan Neelmegh drsureshmohan@... [ap-gto]
To: ap-gto
Sent: Thu, Sep 22, 2016 12:57 pm
Subject: [ap-gto] Park position



I've updated to latest ascom v2 driver and also HC . Perhaps the second time in my life my mount will be out continuously for a week . I see park 0 as fanciful ; can I switch on the mount  the next evening and simply do a goto any star ? What's the procedure 
Thank you
Suresh




Re: AP900 DEC sawtooth guiding

Roland Christen
 

Still no information to work with. need to know the calibration parameter numbers after you do a calibration run.
 
Example: If pixel scale is 1 arc sec per pixel, then Dec movement would be 15 pixels per second. This parameter (15) is then used to determine the amount of move command that is sent to the mount. Therefore if the error is 1 pixel, the mount would be commanded to move 1/15 sec at 1x guide rate. This also means that the loop gain is 100%, which means that a 1 pixel error is compensated by a 1 pixel move command.
 
Knowing the pixel scale and the calibration result (parameter number obtained after calibration run) allow you to know if the loop gain is 100% or not.
 
If calibration number is wrong, your resultant loop gain might be more than 100%. If the parameter number obtained after a cal. run is only 7.5 rather than 15 in the above example, then for every 1 arc second position error the mount gets a 2 arc second (1/7.5 second) move command. Loop gain is now 200%. So, the net result is overshoot after every error with the axis constantly bobbling back and forth. The smaller the number relative to the correct number, the larger the overshoot.
 
Rolando
 
 
 
 

-----Original Message-----
From: anismo@... [ap-gto]
To: ap-gto
Sent: Thu, Sep 22, 2016 12:30 pm
Subject: [ap-gto] Re: AP900 DEC sawtooth guiding



Hi Rolando

I dont have keypad connected to the system. It is only connected to the computer. ASCOM v2 and SGP

The PHD2 settings are
1. Camera pixel size - 8.62 micron (Lodestar x2)
2. Focal length - 382mm (Connected via OAG , so FSQ106 with 0,73 reducer)

I did calibration few times to be sure with calibration steps of 500ms (as well as let PHD2 calculate based on DEC). The calibration always completed without any issue

I also tried with Hystersis as well as resist switch DEC algorithm, as well as with different aggressiveness (all the way to lowest possible aggressiveness).  

Every one of these times, it will guide properly if I start the guiding but once it receives the dither pulse, the star will start jumping between two points and never settle. (almost same amplitude)

Here is one screenshot that I took whe n it was running ok: http://dev1.codelathe.com/url/5pt30yvcupt3

The DEC always stayed below the 0 line.. not sure if I have PA misalignment (I did PA using polemaster and was able to get it calibrated pretty well as per that software).

Thanks!
Anis




Park position

Suresh Mohan
 

I've updated to latest ascom v2 driver and also HC . Perhaps the second time in my life my mount will be out continuously for a week . I see park 0 as fanciful ; can I switch on the mount  the next evening and simply do a goto any star ? What's the procedure 
Thank you
Suresh