HandyDob6 - Two Inch Focuser

This is a 2 inch focuser for the HandyDob6 telescope.  My 3D part is an adapter to connect the Analog Sky Universal 2" Focuser to the HandyDob6 telescope. This 2 inch focuser configuration allows HandyDob6 to see a much wider field sky area than the original 1.25 inch focuser.  It also reduces the weight of the focusing mechanism by 300g compared to the original focuser, which helps compensate for the heavier eyepieces. 

I have used it with the TeleVue Nagler 19mm Type 7, Houdini 20mm, and Celestron Ultima Edge 30mm eyepieces – it works very well.  Eyepieces are held in place by so-called “grip fins” on the 2 inch inner diameter. The telescope's secondary mirror is a bit undersized for 2 inch eyepieces, but the light loss at the field edge is visually insignificant. The focuser is probably not suitable for ultra heavy eyepieces and cameras. 

My adapter has holes for three M5x20mm bolts to mount it on HandyDob6.  Two of the holes are threaded, and the third is just a through-hole.  A long ball head 4mm Allen wrench will be helpful when mounting it on HandyDob6.

The Analog Sky helical focuser mechanism is 3D printed, and is a proprietary design.  I suggest to purchase it here.  You will want to order the “standard” version, as well as the add-on hardware kit. The helical mechanism has a focusing rate of 4mm per turn, and a total travel of 29mm.  The Analog Sky focuser has a two-piece base that engages the helical tube.  There is a nut pocket on the smaller piece, and the provided M4 bolt connects the two pieces of the base.  Friction on the helical motion can be adjusted by loosening the screw that holds the two pieces of the base together, and also by applying the provided graphite pencil to the helical threads. Their add-on hardware kit includes M4 bolts for assembling and mounting the helical mechanism.

Misc. hardware: The adapter has pockets to install two M4 7x7x3mm square nuts for mounting the Analog Sky focuser. The nuts can be found on Amazon, etc.   It also needs three M5x20mm socket head bolts and two washers to mount the adapter to HandyDob6, also available on Amazon.  A long ball-end 4mm Allen wrench will be helpful.

My model incorporates the “Handydob6 - One Piece Focuser” by @somenewguy from MakerWorld as part of the design. It has been substantially revised to accommodate the Analog Sky 2 inch focuser.