Adive on adaptor to connect Canon EOS series compatible tube to Nikon D90 body?

The microscope camera adaptor in my lab fits my friend's Canon EOS series. The connection between the microscope and camera doesn't have any electrical elements involved. What adaptor can I use to mount my Nikon D90?

Added (1). I'd rather not, they're going to charge a lot and I'd rather get an adaptor that will fit on the Canon EOS compatible fixture and onto my Nikon D90 body. I was thinking that camera adaptor outs there should suffice, but wanted to know what to look out for when I'm perusing online for one.

Your microscope supplier should have the right adapter for you.

Just ask them

You have to use an adapter that fits between the microscope and directly onto the Nikon body. You can't use a microscope to Canon adapter and then Canon to Nikon adapter, even if one exists the projected focal plane would miss the camera sensor!

You need to find out exactly what the adapter is… Because it sounds like a T-mount. If so, you can get your own T (or more likely T2, makes no difference either way) for your Nikon body for all of about $10 US.

If the mount is not a T, then you have a problem. There are no adapters to use a Canon EF lens (or microscope mount) to a Nikon body.