Nikon DR-5 right angle finder adapter for Star Adventurer

Posted: 2019-04-18

One of the things I struggled with when testing the star adventurer is that here in south Norway - the latitude is somewhere between 59 and 60° north. That means that the tracker is pointing 60° up and to look through the polar scope you have to bend down and then twist your head up (even on a high tripod).

I have a Nikon DR-5 right angle finder for my DSLR - so let's see if we can fit the two together with a little 3d printing.

First I tried this clip from thingiverse.

Thingiverse clip
Thingiverse clip

This had two issues. One is that the screw thread on the DR-5 outer screw ring didn't sit quite right. The bigger issue is that it clips over the knurled ring on the star adventurer. I need this adjusted to be able to see the scope in focus. This is both for direct viewing due to my eyesight and also through the DR-5 - this has it's own focus ring but needs the adventurer's own ring to bring the focus to a point where it can focus on it properly. This meant that the clip was loose.

Second attempt after looking through a fair number of options out there was to model in Fusion 360. After a few attempts I ended up with the following model (STL file):

Fusion 360 model
Fusion 360 model

The model has three small holes spaced around it where I used a metal M3 screw to in effect tap the holes, then plastic screws to actually grip the star adventurer. The extra black hex on each screw is really a spacer - added to make these easier to use with fingers.

Issues I still have to address here are:

  • Will the tapped small holes keep their grip over time? If not I may need to have thicker walls at this point.
  • The screw thread on the end of the 3d-print where I screw the adapter ring from the DR-5 isn't fitting quite right. I did print a trial piece with M22 holes from pitch 0.5 thru to 2.5 - and the M22 0.5 pitch on the trial piece allowed me to screw the adapter ring in well. For some reason this isn't fitting as pretty as I'd like on the main model.

But - in summary - it holds the DR-5 stable, and (given that I have unscrewed the focus ring on the polar scope a few turns before I fit it) I can use the focus on the DR-5 to view the scope on both of it's 1x and 2x settings.

So - I'm calling this one a success for now :)