I have been using the myfocuser pro2 system with excellent results. Thanks very much Robert!
My question is what is the best practice when setting up focus on a refractor to hold the focuser from extending out with the weight of the camera and accessories when scope is more vertical ?
I have a williams optics GT81 with a 3d printer belt system about 12 to one ratio and I am using coil power to hold the tube. IS this best practice or are you creating a more elaborate gear system so that the you don't need to use coil power ?
thanks
Al
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With so much about astronomy being a field where things have to worked out to one's own satisfaction, I can only offer what works for me.
With the large stellavue refractor, using a planetary Geared PG27 NEMA notor, I can loosen off most of the focuser lock screen so that only a small amout of friction is applied, and the motor can still move.
This helps when the scope goes towards the vertical. i prefer to run things at full steps and not microstep, with coil power on because most of time the scope spends a lot more time being vertical than horizontal
The geared motors tend to hold their position better than non geared when coil power is off.
When working all these things out, like the stellarvude, what I did was
- secure the scope in an upside down position, with front cell down on bench (of course with some felt pads, I am not a fan of scratching things). with the focuser, focus motor, camera etc all attached (power off). Then I played with using focus lock screw etc, with the motor pushing against gravity moving the focusing train upwards (out direction) till I found a good combination of being able to move ok and not have the focus draw tube slip down.
But coil power on should not cause an issue, I have only experienced stepper heat when I did not setup the drv8825 etc chip correctly.
Where I am located, most objects worth imaging are above the meridian and up higher towards zenith so I know what it means to have the refractor pointed vertically. I prefer using OSC cooled cameras like SVX (Starlight express) because of their weight and I so not have the patience to deal with filterwheels.
Many moons ago I did have some numbers as to what was what imaging train weight and comparisons between motor types. microstepping etc, but I have no idea where that is now.
From memory I think I did this in partnership with a user, but I cannot remember who
Last edit: brownrb 2021-10-26
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hi
I have been using the myfocuser pro2 system with excellent results. Thanks very much Robert!
My question is what is the best practice when setting up focus on a refractor to hold the focuser from extending out with the weight of the camera and accessories when scope is more vertical ?
I have a williams optics GT81 with a 3d printer belt system about 12 to one ratio and I am using coil power to hold the tube. IS this best practice or are you creating a more elaborate gear system so that the you don't need to use coil power ?
thanks
Al
Hi Al
With so much about astronomy being a field where things have to worked out to one's own satisfaction, I can only offer what works for me.
With the large stellavue refractor, using a planetary Geared PG27 NEMA notor, I can loosen off most of the focuser lock screen so that only a small amout of friction is applied, and the motor can still move.
This helps when the scope goes towards the vertical. i prefer to run things at full steps and not microstep, with coil power on because most of time the scope spends a lot more time being vertical than horizontal
The geared motors tend to hold their position better than non geared when coil power is off.
When working all these things out, like the stellarvude, what I did was
- secure the scope in an upside down position, with front cell down on bench (of course with some felt pads, I am not a fan of scratching things). with the focuser, focus motor, camera etc all attached (power off). Then I played with using focus lock screw etc, with the motor pushing against gravity moving the focusing train upwards (out direction) till I found a good combination of being able to move ok and not have the focus draw tube slip down.
But coil power on should not cause an issue, I have only experienced stepper heat when I did not setup the drv8825 etc chip correctly.
Where I am located, most objects worth imaging are above the meridian and up higher towards zenith so I know what it means to have the refractor pointed vertically. I prefer using OSC cooled cameras like SVX (Starlight express) because of their weight and I so not have the patience to deal with filterwheels.
Many moons ago I did have some numbers as to what was what imaging train weight and comparisons between motor types. microstepping etc, but I have no idea where that is now.
From memory I think I did this in partnership with a user, but I cannot remember who
Last edit: brownrb 2021-10-26
Thanks very much for your advice and continue work on this amazing project !
Al