Dark Universe Spider installation/Issues

[Cubzilla]

First post so be gentle 🙂 I have upgraded my Skywatcher 150PDS to include the Dark Universe CNC spider , the installation was followed to the letter. My issue is collimation, I have 2 collimated lasers and both show the same issue, when collimating I  can get the Laser to "orbit" the centre doughnut on the primary but when I try to centre the laser in the doughnut the  laser dot disappears !.

As part of my troubleshooting I have moved the secondary towards and back from the primary mirror  by using the centre screw, once in its new position the adjustment screws are advanced to secure the secondary down and collimation is attempted again without success , no amount of repositioning brings the red dot in the centre and bright.. It will always "orbit" the doughnut.

Anyone seen or experienced issues like this ??

Regards Trevor

 

 

[bosun21]

Did you have any problem centering the laser in the centre marking before you changed the spider? Where is the return beam of the laser falling? 

[Cubzilla]

This was a new PDS , and purchased with a view to tuning ( flocking, mirror mask , spider etc ) before first light ,  I have found that I can get it to any position on the centre doughnut ring giving a sharp single laser point, if move it to the centre it's never a pinpoint it diffuses and  fluoresces while the laser is somewhere in the centre..

[michael8554]

How large in diameter is the laser dot compared to the whole donut, and to the inside diameter of the donut ?

Michael