On loan from a friend, I could spend some clear nights with this short-focus flat-field refractor. It has 70mm aperture and 350mm focal lenght, for an F/Ratio of F/4,9. It delivers a nice illuminated field and pinpoint stars almost to the corners of the frame. Some slight blue fringing is present near the corners. Focusing is very critical, and also very temperature-dependent. An autofocuser is almost indispensable to keep control over the focus.
25 December 2019: a Christmas baby
Or actually maybe more still a foetus, as the Soul nebula is often seen as a foetus or a little bear. Imagination! I’ve never seen a Soul in it: how does a soul look like anyhow?
The frames were taken last week Tuesday, in horrible conditions: high clouds, fog, and tons of moisture. Frames were whitened out by the fog, and all street lighting reflecting on the fog.
The image is a mosaic, about 6000×7400 pixels. More then 7 panels were composed with APP to create it. However, due to the fog, soo many gradients were present, I really had to get all tricks out of my sleeves to get a decent picture. It was processed with all parameters in APP at max (Normalisation, blending) and also cropped the outer edges which could not be salvaged. Material used was: Nikon D750, no filters, EQ8; Esprit120, 400mm guidelens with an ASI290MM
Also to be seen at Astrobin