Is there anyone using a 130phq with an eaf and ASIAIR that is willing to share their backlash and auto focus setup numbers? I’m battling auto focus weirdness.
Autofocus dial in
Hi Jeff. I see no one has responded so I will drop some info which MIGHT help. Caveat. I dont use any of the equipment listed except the EAF.
Backlash settings from one persons system wont necessarily match yours, so the other peoples numbers probably wont be of much value.
the step size that will work depends on the Focuser being used, and the CFZ of the OTA.
it wont equate correctly to your system, but on my Takahashi FSQ-106 I use a step size of 30, and with my RC-10 with a Feathertouch 3 inch Focuser and a Microtouch Autofocuser, I increased the step size to 50. both these systems autofocus well.
here is a simple way to get it working.
1. focus the OTA by hand and take images adjusting the position until the stars are as small as possible.
2. add a Bhatnov mask and try and fine tune the manual position as best you can.
3. Note the position, and mark it on the focuser (I use a pencil) and then start an EAF run from the previously obtained Best Focus Position.
4. if the Vee Curve looks more like a Flat Line, and fails, move the Focus position back to the start position and increase the step size. run it again.
5. if you can see a Vee curve, but you are overshooting on the left and right, decrease the step size.
6. you want about 5 or 6 moves from the top of the Vee to the bottom, and perhaps 10 in total from inside of focus to outside of focus.
unsure how much manual adjustment of step size mechanics is available in ASAIR, but just experiment with different step sizes until it works.
Clear Skies and Good Luck.
Backlash settings from one persons system wont necessarily match yours, so the other peoples numbers probably wont be of much value.
the step size that will work depends on the Focuser being used, and the CFZ of the OTA.
it wont equate correctly to your system, but on my Takahashi FSQ-106 I use a step size of 30, and with my RC-10 with a Feathertouch 3 inch Focuser and a Microtouch Autofocuser, I increased the step size to 50. both these systems autofocus well.
here is a simple way to get it working.
1. focus the OTA by hand and take images adjusting the position until the stars are as small as possible.
2. add a Bhatnov mask and try and fine tune the manual position as best you can.
3. Note the position, and mark it on the focuser (I use a pencil) and then start an EAF run from the previously obtained Best Focus Position.
4. if the Vee Curve looks more like a Flat Line, and fails, move the Focus position back to the start position and increase the step size. run it again.
5. if you can see a Vee curve, but you are overshooting on the left and right, decrease the step size.
6. you want about 5 or 6 moves from the top of the Vee to the bottom, and perhaps 10 in total from inside of focus to outside of focus.
unsure how much manual adjustment of step size mechanics is available in ASAIR, but just experiment with different step sizes until it works.
Clear Skies and Good Luck.
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I've just installed an EAF and that's exactly how I did it. The curve isn't textbook but it's still finding best focus.
Jeff Clayton:
Is there anyone using a 130phq with an eaf and ASIAIR that is willing to share their backlash and auto focus setup numbers? I’m battling auto focus weirdness.
My .02. The only time I ever had problems with my EAF is when the grub screws had come loose. This made it impossible to dial in the EAF. I encourage you to check this first. It is now a routine part of my setup to check the tightness of the grub screws.
Assuming you did this, to get the back lash set up properly, set your fine to something small (mine is 10) and your course to something "large'ish" (I set mine to 250 for determining the backlash, I later set it to 100 for normal use). Next, use the Auto focus controls to go in one direction (doesn't matter which). You need to go in that direction until the press to move makes the EAF move the focus adjustment immediately (2 - 4 times is probably enough). Now, change the AF to a fine setting and go in the OPPOSITE direction until you see the adjustment knob on your scope begin to move. You may need to put a mark or a piece of tape or something to make sure you see this movement. You need to count the number of presses in the opposite direction to make the focus knob move. The (number of presses) X (fine step size) == backlash. Enter this value into the backlash. To test, go back in to your course setting. Note where your mark is. Press the button to move one way, wait for it to finish, and press the button for it move in the OPPOSITE direction. The mark should be in the same spot it began. If you want to get more accurate, you can set your "fine" to a smaller step but you'll end up counting more steps to find the backlash.
In use, my course is set to 100, my fine is set to 10, my backlash is set to 50 and everything works fine. But I advise you that my backlash is not likely to be yours. Even among the same make and model, there is bound to be some differences in the focal gear trains. Hope this helps.
Helpful Engaging
Is your focuser is a standard crayford, or rack & pinion ? The former may exhibit creep or slip, the latter cannot.
Concise
For backlash just follow the instructions in the manual.
Set the rough move to like 50 steps and the fine to something like 5 steps. Move the focused with the rough move a few times in one direction, enough to see the focuser move. Then switch to fine. Tap and count how many fine focus moves it takes to make the fine focusing wheel to move.
How many fine moves times 5 (cause that’s what your steps is set at in this example) is your backlash. The manual might say different numbers for step size, I don’t remember, but that’s the process for finding backlash with a focuser like on the 130PHQ.
Set the rough move to like 50 steps and the fine to something like 5 steps. Move the focused with the rough move a few times in one direction, enough to see the focuser move. Then switch to fine. Tap and count how many fine focus moves it takes to make the fine focusing wheel to move.
How many fine moves times 5 (cause that’s what your steps is set at in this example) is your backlash. The manual might say different numbers for step size, I don’t remember, but that’s the process for finding backlash with a focuser like on the 130PHQ.
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Watch Patriot Astro's video, you can't go wrong.
https://youtu.be/lHrfaR7A0L0?si=hc85vBrD4Rng4EBM
After watching his video, I did the following.
Manually find focus and mark the tube with a pencil or something that's not permanent.
Rack the focuser all the way in, attach the EAF and zero it out.
Move the EAF, within NINA, until your marks are back to where you started, fine tune with a Bahtinov mask, take note of the position in NINA.
Take a few subs and note the average HFR. Using NINA's focusing tab move the focuser in or out, one direction only, until the HFR is 4x's - 6x's where you started.
So, if your HFR is 2.86 at best focus with the mask, round that to 3, 3x4=12 so when your HFR is around 12.
Take the difference from your initial position and current position and divide that number by 4, that's your "Autofocus step size".
Set your "Autofocus initial offset steps" to 4.
Set your backlash IN/OUT to out, start with maybe 500. It's ok to have too large of a number there, but not too small. You can experiment with this setting after you get it working.
Of course, you can tweak those settings until you get a nice V curve.
https://youtu.be/lHrfaR7A0L0?si=hc85vBrD4Rng4EBM
After watching his video, I did the following.
Manually find focus and mark the tube with a pencil or something that's not permanent.
Rack the focuser all the way in, attach the EAF and zero it out.
Move the EAF, within NINA, until your marks are back to where you started, fine tune with a Bahtinov mask, take note of the position in NINA.
Take a few subs and note the average HFR. Using NINA's focusing tab move the focuser in or out, one direction only, until the HFR is 4x's - 6x's where you started.
So, if your HFR is 2.86 at best focus with the mask, round that to 3, 3x4=12 so when your HFR is around 12.
Take the difference from your initial position and current position and divide that number by 4, that's your "Autofocus step size".
Set your "Autofocus initial offset steps" to 4.
Set your backlash IN/OUT to out, start with maybe 500. It's ok to have too large of a number there, but not too small. You can experiment with this setting after you get it working.
Of course, you can tweak those settings until you get a nice V curve.
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