Tilting a C-ERF

[michael8554]

I'm looking for a better way of tilting my 70mm C-ERF inside a 73mm ID cell.

I currently use two small pieces of cardboard diametrically opposite each other, on either side of the ERF, but it's not very rigid.

Ideally I'd like two metal rings 73mm OD, say 71mm ID, and tapering 1mm to 0.5mm in thickness, but where to get, or make?

Michael 

[Uplooker]

Where is the the cell / ERF located - internally or at the objective end? You only need a very small tilt to reduce reflections, normally 1 or 2 degs.

Ian

[michael8554]

The ERF is directly in front of the objective.

I sort of recollect a 1/2 mm tilt being suggested.

[Merlin66]

For an objective mounted ERF about 2mm or so tilt across the diameter.

You could safely use a similar arrangement to the one you currently have but use some small cork spacers.

[michael8554]

Well I found it hard to keep bits of cardboard or cork in place while tightening the lens cell retaining ring.

So I came up with this idea:

Two tilt-rings made from gardening wire, this is one of them.

One placed under the ERF, the other on top, the thicker sections diametrically opposite.

The thick overlapping ends rest on the edge of the ERF but only impinge a small amount into the clear aperture of the retaining ring.

After soldering the ends and wrapping with black tape I suddenly thought:

"shrink-wrap tubing"!   Too late, maybe on the MkII.

Top tilt-ring in place

Retaining ring screwed on. Need to blacken the rest of the tilt-ring

Lens hood attached