Nikkor 300mm F2.8 further test

I discovered that the lens I purchased (used) had a UV drop-in filter inserted. So I removed that filter and tested again the last night, under a full Moon… On an EQ8 without any guiding, did 18 times 60 second 800ISO shots on F/4 using BackYardNikon.

There are still skewed stars left in the corners, especially to the left lower side. But that might fall within normal DSLR tolerances. I do not understand the assymetry though / left to right.

The only thing that still worries me is the darker circular donut in the middle of the image. It might be related to the large hood that this lens has, a sunshade. I need to test it without the hood (and with a dew band).

The bright star in the middle is Deneb, the red nebulosity at the top is the Pelican.

300mm F2.8 Nikkor

This lens is a beauty and has been since long on my wishlist. The initial tests indicate some slight defocus on the left side of the image ( at F2.8). But sharp enough overall and especially in the centre. The intended use of this lens is to exploit it’s fast F/Ratio: fast comet imaging with the Nikon D750 / Large Milky Way or nebula complexes with the Nikon D750 and narrow band imaging with the ASI183mm.

Some test shots (unguided)

Crop of the rising Moon 300mm F2.8 Nikkor @ F4
M57 6 x 30″ on ISO400 @ F2.8, slightly cropped ; no guiding on an EQ8