[avandonk]

Thanks all, for the comments.

Mike it is difficult to put an aperture of 56mm in front of a lens of 104mm clear aperture. The resulting image quality is of course superb as you are only using the central almost perfect region of the optical train.

All secondary aberrations are almost non-existant and any diffuse scattering inside the lens gone.

In the past when I used the lens' iris the diffraction spikes on the bright stars looked terrible, at least to me.

The fridge gives me the edge with the very weak nebula and dust signal at my light polluted site. Notice how the dust near Antares now has the colour of the faint Cometary Globules rather than being swamped with orange from internal scatter from the very bright Antares.

It feels as if I have just started to use this lens for the first time..

Bert