[Sunfish (Ray)]

So the mirror and secondary are ok if you look closely with a loupe?

Just corrosion in the tube from differing metals used in construction and being left outside. ?

The tube I think is aluminium and can be cleaned and repainted. There are some Images on CN of this. The little bolts I know are very poor zinc coated and could be replaced with anything not too long.

My tube came a little loose and I reseated and tightened the bolts and that worked. Perhaps you could repaint the existing tube and reassemble without too much trouble but I would not touch the focus tubes except to clean it . And don’t clean the mirrors like I did. It is a pain. Don’t even touch them with anything other than puffer air.

The tube and base can not be parted I think except by those with optical instruments to realign.

Are you sure the focus tube is corroded metal?