It is finally here! A focuser worthy of its job - the Starlight Instruments FeatherTouch 3" focuser, adapted for the Takahashi FSQ-85ED telescope. The following is essentially a list of parts that make up the focuser:
- FTF3015B-A: FeatherTouch 3" focuser with 1.5" travel
- A30-1903-85: Takahashi FSQ-85ED telescope-side adapter
- EC30-1905-72: Takahashi M72 camera-side adapter
Since the camera-side has a Takahashi M72 thread, I can use the regular Takahashi adapters and accessories as if I was using the stock focuser. The 1.5" of focuser travel is apparently as high as it can go for the Takahashi FSQ-85ED telescope, but is more than enough as it is nearly as much as the stock focuser's travel (and my imaging camera focuses less than half-way out as it is).
On receiving the FeatherTouch focuser, I had to add on the Lakeside Motorised Focuser bracket and motor, for autofocus. I had two spare Lakeside brackets for FeatherTouch focusers but unfortunately these were for smaller focusers and a bit to my surprise, did not match this 3" focuser precisely. This 3" focuser has two screws to adjust the tension in the focuser. One is just a screw and another is a thumbscrew. The hole on the Lakeside bracket matched up with the screw, so in order to hold the bracket in place, I swapped the screw and the thumbscrew on the focuser, so that the thumbscrew could go through the bracket and hold it in place. I used three stacked penny washers to account for the extra height and produce a solid fit. Unfortunately the two smaller holes on the Lakeside bracket that allow two long screws to replace the ones holding the FeatherTouch focuser together, do not match up with the screws on this larger focuser. They do lie below the bracket however so a bit of drilling can sort that out. The issue then is that the long screws have a thicker thread on this focuser than the smaller version, and given that my local stores do not seem to stock the screws I need, I did not bother at all. The bracket is therefore held in place purely by the thumbscrew pushing down on the three stacked penny washers and the motor attached to the axle. I have tightened it all pretty heavily and it seems perfectly stable with no play whatsoever, so it should all be good to go.
On receiving the FeatherTouch focuser, I had to add on the Lakeside Motorised Focuser bracket and motor, for autofocus. I had two spare Lakeside brackets for FeatherTouch focusers but unfortunately these were for smaller focusers and a bit to my surprise, did not match this 3" focuser precisely. This 3" focuser has two screws to adjust the tension in the focuser. One is just a screw and another is a thumbscrew. The hole on the Lakeside bracket matched up with the screw, so in order to hold the bracket in place, I swapped the screw and the thumbscrew on the focuser, so that the thumbscrew could go through the bracket and hold it in place. I used three stacked penny washers to account for the extra height and produce a solid fit. Unfortunately the two smaller holes on the Lakeside bracket that allow two long screws to replace the ones holding the FeatherTouch focuser together, do not match up with the screws on this larger focuser. They do lie below the bracket however so a bit of drilling can sort that out. The issue then is that the long screws have a thicker thread on this focuser than the smaller version, and given that my local stores do not seem to stock the screws I need, I did not bother at all. The bracket is therefore held in place purely by the thumbscrew pushing down on the three stacked penny washers and the motor attached to the axle. I have tightened it all pretty heavily and it seems perfectly stable with no play whatsoever, so it should all be good to go.
Thankfully the optical train is not in any way attached to the Lakeside bracket, so the weight that is currently on it is all that will be on it. I feel confident this will hold together perfectly well anyway. Should that confidence dissolve in any way, I will end up ordering a perfectly-made Lakeside bracket and set of screws straight from Lakeside, to replace the bracket entirely. For now however, it will venture on! I intend on replacing my Takahashi FSQ-85ED stock focuser for this one this coming weekend, when I will be staying at e-EyE, primarily to teach the owner PixInsight! :)