Lens Micro Adjustment Collars

[Coco]

Ever tried to focus an 200mm f/2.8 lens on a star field?  It’s very difficult to get FWHM  spot on across the field.. ..
Taking advice from Olly P  that its a good idea to have one I decided to make my own..

Two hours of fun and less than a fiver ...   ( nice to have the alloy tube in stock ready )

Think I'll make another for the 400/5.6L so I dont have to take it off once its fitted..
 

[Psychobilly]

Nice

It's worth spending a bit if time naking sure that the collars are centred properly on the lens...

Peter...

Badly typed on my Galaxay S4 in Tapatalk4

[Gina]

I tried that manual mechanical method at first without much success.  Now I use those mini stepper motors with the 64:1 built-in gearbox connected to the focus sleeve with timing pulley on the motor shaft and timing belt to the focus sleeve.  You can improve  the drive from the belt to the sleeve by sticking the belt on with hot melt glue.  The glue sticks to the focus sleeve but not the belt and forms a pretty effective timing pulley.  The stepper motor is driven from an Arduino via a ULN2003 driver chip.

[Coco]

I tried that manual mechanical method at first without much success.  Now I use those mini stepper motors with the 64:1 built-in gearbox connected to the focus sleeve with timing pulley on the motor shaft and timing belt to the focus sleeve.  You can improve  the drive from the belt to the sleeve by sticking the belt on with hot melt glue.  The glue sticks to the focus sleeve but not the belt and forms a pretty effective timing pulley.  The stepper motor is driven from an Arduino via a ULN2003 driver chip.

Thanks Gina... got a picture

I tried the skywatcher 9V focuser and elastic band over the focus bit, it held back some stored up energy in the band and released it at will knocking the focuser out

[Gina]

Thanks Gina... got a picture

I tried the skywatcher 9V focuser and elastic band over the focus bit, it held back some stored up energy in the band and released it at will knocking the focuser out

[Coco]

Thats terrific Gina... love the tensioner

[Gina]

Thank you   Crude but effective