anyone using AUTOFOCUS WITH ASTRO PHOTOGRAPHY TOOL?
When Setting up APT in the PdF It mentions setting Backlash in the Ascom. But i dont see a setting in the Ascom drv..
how are you guys that use APT dealing with Backlash and Autofocus with APT?
i measured mine.
once i move in one direction it takes 125 TO 150 1/2 STEPS to see movment in the other direction
50 TO 60 step at Fullstep
thats measured at the focuser using a dial indiator micrometer
going thru my belt and pulley setup
at the Gear on Stepper it has 25. 1/2 STEPS of Backlash
seems like alot
thanks
bjj
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
The myFocuser software does not support backlash. It is not normally handled by ASCOM or within the driver itself (unless it is a constant - and even then it will vary over time due to wear and tear). There are no current plans to put this backlash compensation in. If you have good arduino coding skills I can send you the code fragments that have been explored so far with backlash compensation - but no support is offered.
Client apps, in my opinion, are the best place to implement backlash, not the driver. Unless the driver has constant backlash in the system or a way of updating the backlash values and remembering them, its pointless to add backlash into the focuser code. [Note FocusMax and Maxim DL allows user to specify backlash compensation]. It shouldnt really be done twice in two different places.
I am really surprised you have that amount of backlash.For my direct drive coupling there seems to be, for me, virtually 0 backlash.I am using both a NEMA17-PG5 and PG27 stepper with direct drive. How many steps do you have within the CFZ? What is your step size setting in APT and is stepsize enabled in the focuser driver?
It might be worhwhile asking APT developer if backlash settings can be incorporated into APT to help with focus issues? Along the lines of MaximDL and FocusMax and ScopeFocus
Cheers
Robert
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
HI Robert,
my backlash is bad because of the Belt system i use. if i tighten belt up good . It puts stress on my focuser, this Belt Sytem was crap.
so Im going with a Direct Drive, i finally figured out how to get the knob off my Focuser, and i
Finally found a Flex coupler with the correct openings to fit my scope and Nema11 i am using.
once i get direct drive going, i should be good.
if my calculations are correct my CFZ is 14 fullsteps or 28 1/2 steps which is the setting i use. 1/2steps.
as for my APT Step size setting i am not sure what it should be. On the APT Focuser Screen ,
Step size is 10.
What should the APT Step size set to?
(i have a hardtime with APT and ususlly give up and go back to BYEOS,)
in Myfoucuser2 settings i do have Stepsize enabled i have it set at 2.4 again if my calculation are right thats 2.4 mic at fullsteps.
should that setting be 2.4
or 1.2 since i use 1/2 steps?
I have no problem focusing with the Controller or with either APT or BYEOS manually.
but i have only got the APT autofocuse to work for me on 1 evening.
i havent had a desent session in a few outtings.
Guiding problems,PC problems,cable problems, New pc problems, Win10 USB problems
an then theres the clouds.
i want to learn APT but i do find BYEOS easier
thanks
bj
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi BJ
For myFocuser2 if its 2.4 at fullsteps but you are using halfsteps it will be half that - 1.2
You need to calculate the stepsize as described in the manual. I think the manual says go 1000 full steps and measure the difference etc. Once you have this number then its for full teps only. If you use 1/2 steps then divide by 2.
APT etc require the step size to be correct to auto focus - so it needs to be enabled and have a valid value.
You are not alone with issues!
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
R,
So if i am using half steps i set myfocuser2 setting to 1.2 ?
Now on your secound pargraph your are referring to calulating step size per the APT manual or your manual ?
I thought the "Step Size" in the APTfocuse window was just how many step it would move if to press the forward or reverse button i put in 1000 and press ">" it move 1000 steps or ">>" it move 5x
or are you referring to the MAX STEP or MIN STEP setting in APT?
B
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
First measure how much your focuser moves for one full revolution of the focuser knob (distance in milli-meters). Then divide this number by the number of steps per 1 revolution of your stepper motor. The answer is the distance that the focuser moves per step (called Step Size).
Distance moved per stepper motor step = distance one full focuser rotation / stepper motor steps per revolution
So what that means above is try to find out how much the focuser moves per step. You will need to calculate this. For me I set the focuser at half steps (because that is what I use) and at say halfway out, noted the focuser position on the program, then slowly stepped the stepper out each time till the focuser had done one revolution of the focuser knob. When it had done one full revolution of the focuser knob (I marked it so I could tell it was in the relative same position at the end of the moves), I then subracted the original position from the current position. This gives me the number of steps per full rotation of the focuser knob. Then I used a digital capiler to note how far the focuser tube had moved in one full revolution. This gave me the distance. So to get stepsize I divided distance by number of steps. I got a number of 7.1
I would then enter the value into the Windows Program (On the ExtraSettings form - StepSize was calculated at 7.1) also in the motorspeed change part set both Enable in controller and Update on Connect to Yes) before connection to the focuser. ON connecting the stepsize will be sent to the controller and also enabled in the controller. (You can also use the ASCOM to do this as the driver has similar settings). Once the stepsize has been specified and enabled, you can close the Windows program
NOW FOR APT
In APT, Click on GEAR tab. In the focuser Section there is a place to enter Setp Size. Here you would enter the value that you determined BUT first - divide your CFZ by your stepsize value - and enter that into APT as StepSize.
And then thats it.
B
I used a digital caliper. At the start, with the focuser positioned about half way out, I measured from the end of the focuser tube back to the face of the focuser housing. I set this to 0 point. Then I moved the focuser out till it looked like the focuser knob had moved one full revolution. Then I measured that and got a distance reading in mm.
NOTE: Use mm in the distance measurement - NOT feet/inches
Last edit: brownrb 2016-08-16
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Just looked at the APT help on Step Size
Defines how many positions to change on every move step. The button "..." allows creation/selection of different step size profiles. When Step size control is focused you can use arrow up/down keys to scroll through the profiles you have defined.
That is definately not the way that MaximDL uses Step Size. ASCOM is set to return the step size in microns that a focuser moves in one step.
This is from the MaximDL Manual
Also essential is the Focuser Step Size. Some digital focusers know what this is inherently; you can click the Auto button to fill in the information. Other digital focusers do not have this information; they are just motors hooked up to focusers from other manufacturers. In this case, take out a ruler! Move the focuser 1000 steps, measure the distance it moves, and divide that by 1000. Enter that into the Focuser Step Size (be sure to set Microinches or Microns as appropriate). (Tip: if you cannot see the focuser move, as for a Schmidt-Cassegrain telescope, focus the telescope with an eyepiece, move the focus out 1000 steps, and then pull the eyepiece out of the focuser until the image is sharp. Measure the distance the eyepiece is moved.)
For APT and FocusMax
Calculating Step Size
The next step is to measure how far your focuser moves per step. To do this setup a dial indicator on your focuser and set it to zero. Now move your focuser a known amount of steps and and note the change on the dial indicator. You should move your focuser enough so that you can easily note a large change on the dial indicator. Ideally you should move the focuser 20mm or more.
Assuming that moving 1000 steps moved the focuser 40mm then you know that your focuser moves 4 microns (0.004mm) per step.
Divide your CFZ size by the step size - if CFZ = 98 microns then this means that to move 98 microns takes your focuser roughly 25 steps. This is what you should set your Step Size value to be as you're guaranteed to sample this value once and only once.
So for APT and FocusMax, set the value of step size in the application (NOT in the controller) to CFZ / Stepsize in Controller
So, set the controller stepsize to the calc value (above example would be 4.0) and enable it. Then in the application APT, set the stepsize value to be about your calculated CFZ divided by your controllers stepsize value.
Is that a bit clearer?
Cheers
R
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
R,
i followed your instruction on p26, I also found your EXCEL Sheet and edited to match my numbers and Scope.
my Focuser on my 8" Newt f3.9 moves 13mm per revolution
13 / 5370 = .0024 Step Size
my CFZ
3.9 x 3.9 x 2.2 = 33 Microns
33 / 2.4 = 14
33 / 1.2 = 28
your saying since i use Halfsteps i use 1.2 as my Stepsize in The Apt Gear Tab?
i hope it is right ;-)
while on the APT Subject.
in the Auto-Focus AID Box Settings Window.
Threshold: , I understand this setting
Fine Focuser Step: What do you have Here?
Course Focuser Step: What do you have here?
i’m sure i will have to work this out after i get my direct drive connected, just curious of these settings
I do not have Maxim or Focusmax so i did not know that but i follow what you saying,
and once i get my direct drive connection to my focuser i should get a better response
i read the APT forum but not much chatter and nobody uses your Myfocuser.
thank you taking the time for that explanation.
cheers
b
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
B
Ok, so it worked out that your cfz = 33 and step size (hal) is 1.2, and there are 28 steps within the CFZ. So 28 is the number you use in APT - basically APT uses a metric of stepsize which means - how many stepper steps do I need to move in order to go from one CFZ to another - in your case 28.
As noted, this is not consistent with the normal meaning of StepSize in other apps or ascom.
For me,
I have settings SS=1.58u/CFZ=71u
I set step size to 1.58
I set the fine focuser steps to be 10-20 (note 20 * 1.58 is about 1/2 CFZ size)
Then I set coarse focus to be more than one CFZ size, like 50-55
At end of day values depend on your system (scope + optics)
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Backlash using APT
Last edit: bj jones 2016-08-14
anyone using AUTOFOCUS WITH ASTRO PHOTOGRAPHY TOOL?
When Setting up APT in the PdF It mentions setting Backlash in the Ascom. But i dont see a setting in the Ascom drv..
how are you guys that use APT dealing with Backlash and Autofocus with APT?
i measured mine.
once i move in one direction it takes 125 TO 150 1/2 STEPS to see movment in the other direction
50 TO 60 step at Fullstep
thats measured at the focuser using a dial indiator micrometer
going thru my belt and pulley setup
at the Gear on Stepper it has 25. 1/2 STEPS of Backlash
seems like alot
thanks
bjj
Hi BJ
I also use APT.
The myFocuser software does not support backlash. It is not normally handled by ASCOM or within the driver itself (unless it is a constant - and even then it will vary over time due to wear and tear). There are no current plans to put this backlash compensation in. If you have good arduino coding skills I can send you the code fragments that have been explored so far with backlash compensation - but no support is offered.
Client apps, in my opinion, are the best place to implement backlash, not the driver. Unless the driver has constant backlash in the system or a way of updating the backlash values and remembering them, its pointless to add backlash into the focuser code. [Note FocusMax and Maxim DL allows user to specify backlash compensation]. It shouldnt really be done twice in two different places.
I am really surprised you have that amount of backlash.For my direct drive coupling there seems to be, for me, virtually 0 backlash.I am using both a NEMA17-PG5 and PG27 stepper with direct drive. How many steps do you have within the CFZ? What is your step size setting in APT and is stepsize enabled in the focuser driver?
It might be worhwhile asking APT developer if backlash settings can be incorporated into APT to help with focus issues? Along the lines of MaximDL and FocusMax and ScopeFocus
Cheers
Robert
HI Robert,
my backlash is bad because of the Belt system i use. if i tighten belt up good . It puts stress on my focuser, this Belt Sytem was crap.
so Im going with a Direct Drive, i finally figured out how to get the knob off my Focuser, and i
Finally found a Flex coupler with the correct openings to fit my scope and Nema11 i am using.
once i get direct drive going, i should be good.
if my calculations are correct my CFZ is 14 fullsteps or 28 1/2 steps which is the setting i use. 1/2steps.
as for my APT Step size setting i am not sure what it should be. On the APT Focuser Screen ,
Step size is 10.
What should the APT Step size set to?
(i have a hardtime with APT and ususlly give up and go back to BYEOS,)
in Myfoucuser2 settings i do have Stepsize enabled i have it set at 2.4 again if my calculation are right thats 2.4 mic at fullsteps.
should that setting be 2.4
or 1.2 since i use 1/2 steps?
I have no problem focusing with the Controller or with either APT or BYEOS manually.
but i have only got the APT autofocuse to work for me on 1 evening.
i havent had a desent session in a few outtings.
Guiding problems,PC problems,cable problems, New pc problems, Win10 USB problems
an then theres the clouds.
i want to learn APT but i do find BYEOS easier
thanks
bj
Hi BJ
For myFocuser2 if its 2.4 at fullsteps but you are using halfsteps it will be half that - 1.2
You need to calculate the stepsize as described in the manual. I think the manual says go 1000 full steps and measure the difference etc. Once you have this number then its for full teps only. If you use 1/2 steps then divide by 2.
APT etc require the step size to be correct to auto focus - so it needs to be enabled and have a valid value.
You are not alone with issues!
R,
So if i am using half steps i set myfocuser2 setting to 1.2 ?
Now on your secound pargraph your are referring to calulating step size per the APT manual or your manual ?
I thought the "Step Size" in the APTfocuse window was just how many step it would move if to press the forward or reverse button i put in 1000 and press ">" it move 1000 steps or ">>" it move 5x
or are you referring to the MAX STEP or MIN STEP setting in APT?
B
B.
pg 26 of myFocuserPro2 pdf
First measure how much your focuser moves for one full revolution of the focuser knob (distance in milli-meters). Then divide this number by the number of steps per 1 revolution of your stepper motor. The answer is the distance that the focuser moves per step (called Step Size).
Distance moved per stepper motor step = distance one full focuser rotation / stepper motor steps per revolution
So what that means above is try to find out how much the focuser moves per step. You will need to calculate this. For me I set the focuser at half steps (because that is what I use) and at say halfway out, noted the focuser position on the program, then slowly stepped the stepper out each time till the focuser had done one revolution of the focuser knob. When it had done one full revolution of the focuser knob (I marked it so I could tell it was in the relative same position at the end of the moves), I then subracted the original position from the current position. This gives me the number of steps per full rotation of the focuser knob. Then I used a digital capiler to note how far the focuser tube had moved in one full revolution. This gave me the distance. So to get stepsize I divided distance by number of steps. I got a number of 7.1
I would then enter the value into the Windows Program (On the ExtraSettings form - StepSize was calculated at 7.1) also in the motorspeed change part set both Enable in controller and Update on Connect to Yes) before connection to the focuser. ON connecting the stepsize will be sent to the controller and also enabled in the controller. (You can also use the ASCOM to do this as the driver has similar settings). Once the stepsize has been specified and enabled, you can close the Windows program
NOW FOR APT
In APT, Click on GEAR tab. In the focuser Section there is a place to enter Setp Size. Here you would enter the value that you determined BUT first - divide your CFZ by your stepsize value - and enter that into APT as StepSize.
And then thats it.
B
I used a digital caliper. At the start, with the focuser positioned about half way out, I measured from the end of the focuser tube back to the face of the focuser housing. I set this to 0 point. Then I moved the focuser out till it looked like the focuser knob had moved one full revolution. Then I measured that and got a distance reading in mm.
NOTE: Use mm in the distance measurement - NOT feet/inches
Last edit: brownrb 2016-08-16
Hi BJ
Just looked at the APT help on Step Size
Defines how many positions to change on every move step. The button "..." allows creation/selection of different step size profiles. When Step size control is focused you can use arrow up/down keys to scroll through the profiles you have defined.
That is definately not the way that MaximDL uses Step Size. ASCOM is set to return the step size in microns that a focuser moves in one step.
This is from the MaximDL Manual
Also essential is the Focuser Step Size. Some digital focusers know what this is inherently; you can click the Auto button to fill in the information. Other digital focusers do not have this information; they are just motors hooked up to focusers from other manufacturers. In this case, take out a ruler! Move the focuser 1000 steps, measure the distance it moves, and divide that by 1000. Enter that into the Focuser Step Size (be sure to set Microinches or Microns as appropriate). (Tip: if you cannot see the focuser move, as for a Schmidt-Cassegrain telescope, focus the telescope with an eyepiece, move the focus out 1000 steps, and then pull the eyepiece out of the focuser until the image is sharp. Measure the distance the eyepiece is moved.)
For APT and FocusMax
Calculating Step Size
The next step is to measure how far your focuser moves per step. To do this setup a dial indicator on your focuser and set it to zero. Now move your focuser a known amount of steps and and note the change on the dial indicator. You should move your focuser enough so that you can easily note a large change on the dial indicator. Ideally you should move the focuser 20mm or more.
Assuming that moving 1000 steps moved the focuser 40mm then you know that your focuser moves 4 microns (0.004mm) per step.
Divide your CFZ size by the step size - if CFZ = 98 microns then this means that to move 98 microns takes your focuser roughly 25 steps. This is what you should set your Step Size value to be as you're guaranteed to sample this value once and only once.
So for APT and FocusMax, set the value of step size in the application (NOT in the controller) to CFZ / Stepsize in Controller
So, set the controller stepsize to the calc value (above example would be 4.0) and enable it. Then in the application APT, set the stepsize value to be about your calculated CFZ divided by your controllers stepsize value.
Is that a bit clearer?
Cheers
R
R,
i followed your instruction on p26, I also found your EXCEL Sheet and edited to match my numbers and Scope.
my Focuser on my 8" Newt f3.9 moves 13mm per revolution
13 / 5370 = .0024 Step Size
my CFZ
3.9 x 3.9 x 2.2 = 33 Microns
33 / 2.4 = 14
33 / 1.2 = 28
your saying since i use Halfsteps i use 1.2 as my Stepsize in The Apt Gear Tab?
i hope it is right ;-)
while on the APT Subject.
in the Auto-Focus AID Box Settings Window.
Threshold: , I understand this setting
Fine Focuser Step: What do you have Here?
Course Focuser Step: What do you have here?
i’m sure i will have to work this out after i get my direct drive connected, just curious of these settings
I do not have Maxim or Focusmax so i did not know that but i follow what you saying,
and once i get my direct drive connection to my focuser i should get a better response
i read the APT forum but not much chatter and nobody uses your Myfocuser.
thank you taking the time for that explanation.
cheers
b
B
Ok, so it worked out that your cfz = 33 and step size (hal) is 1.2, and there are 28 steps within the CFZ. So 28 is the number you use in APT - basically APT uses a metric of stepsize which means - how many stepper steps do I need to move in order to go from one CFZ to another - in your case 28.
As noted, this is not consistent with the normal meaning of StepSize in other apps or ascom.
For me,
I have settings SS=1.58u/CFZ=71u
I set step size to 1.58
I set the fine focuser steps to be 10-20 (note 20 * 1.58 is about 1/2 CFZ size)
Then I set coarse focus to be more than one CFZ size, like 50-55
At end of day values depend on your system (scope + optics)
R,
Thanks your explanations helps me alot.
Thought this might interest you BJ -
Ive used it with good results with Nebulosity
http://www.scopefocus.info/scopefocus-ascom