What a surprise find!.
I was not too sure what I got into when I placed the order for the low-priced offer T-mount 400mm F6.3, believed to be a Tokina RMC, as sold under the Photax name, and also available as an Astranar, Impakt, D&N, Prinz-Galaxy, and many others.
The 4 elements in a 3-groups dual-ring preset 'long-tube' telescope have their fair share of accolades, with most reviewers commenting on its sharpness, and with the fair amount of fungal infection, I found within the elements of the lens, a lower contrast threshold. Had the camera mounted via a built-in tripod mount for these shots (800mm equivalent on the 2x crop sensor), taken wide-open (@ 6.3 of course), and the images post-processed.