Hello there. I’m installing the FC2 on a Celestron SCT. The physical installation went very easily, but I’m curious what I need to do to set initial limits. This is a new telescope for me, and I am new to electronic focusing.
Is there a documented process for setting in/out limits so I don’t accidentally cause damage? A calibration process?
I understand the focus controller application has the ability to set limits, what I am looking for is the proper way to identify those limits for my scope. For instance, the Celestron electronic focuser has a calibration process where it runs the focus in/out and automatically determines the limits and sets the max to be prior to those limits. I assume I'll be conducting a similar process (albeit manually possibly) but I am just not sure the best way to go about it. What happens if the the focuser hits a mechanical limit? Does the motor sense that and prevent further travel in that direction?
I can’t see to find anything on this.
Thanks.
Initial (limits) setup?
Re: Initial (limits) setup?
Answering myself, since I am not sure how often people check this board. I experimented today a bit and tried to do this myself. How is my process?
I removed the pully from the focus knob and ran it fully out/in to determine how many rotations it took for the entire range.
I then found that the motor turns the knob clockwise (in my setup at least) from zero.
I rotated the knob fully out (counter-clockwise) and then turned it in one complete turn (to give a buffer from the stopping point).
In the focus controller app, I set the motor to zero at this point. I assembled the pully and belt.
I ran the motor for one full rotation to see what position (number of steps) that puts me. I then multiplied that number by the number of full rotations I have in my range.
That gave me a maximum point, and then subtracted the buffer rotations from both ends. IE, 30 full rotations for complete range, subract one from each end gives a safe range of 28. (these aren't the exact numbers but easy to explain (and close)).
I then multiplied the number of steps for a single rotation by 28 to get my maximum (safe) limit).
My 0 point is already one turn from full outward rotation, and now my max limit is (approx) a full turn from full inward rotation.
I then divided that maximum limit number by 2, and that is my approximate halfway point. I went to that position, and will use that as a starting point moving forward.
Was my approach reasonable?
I removed the pully from the focus knob and ran it fully out/in to determine how many rotations it took for the entire range.
I then found that the motor turns the knob clockwise (in my setup at least) from zero.
I rotated the knob fully out (counter-clockwise) and then turned it in one complete turn (to give a buffer from the stopping point).
In the focus controller app, I set the motor to zero at this point. I assembled the pully and belt.
I ran the motor for one full rotation to see what position (number of steps) that puts me. I then multiplied that number by the number of full rotations I have in my range.
That gave me a maximum point, and then subtracted the buffer rotations from both ends. IE, 30 full rotations for complete range, subract one from each end gives a safe range of 28. (these aren't the exact numbers but easy to explain (and close)).
I then multiplied the number of steps for a single rotation by 28 to get my maximum (safe) limit).
My 0 point is already one turn from full outward rotation, and now my max limit is (approx) a full turn from full inward rotation.
I then divided that maximum limit number by 2, and that is my approximate halfway point. I went to that position, and will use that as a starting point moving forward.
Was my approach reasonable?
Re: Initial (limits) setup?
You can also set the motor zero point or any position point from the supplied software or ASCOM setting focus driver.