irised open

[IQU3838]

Hi,

Could anyone help me with the term "irised open" in the following sentence?
Thank you very much.

We made it to the ship in about five minutes; there was a minute or two of docking negotiations as a shuttle bay door irised open, accepted the shuttle, and closed again.

I check out the dictionary and only know that irised is something about rainbow, so I really can't figure out what it means in the aforementioned context.

[Rover_KE]

It's a reference to the type of door shown here.

Rover

[BobK]

I've never met 'iris' used as a verb, but it may well be used with reference to this sort of door, which - to a limited extent - mimics the dilation of the pupils (which could be seen as a shrinking of the band of iris visible around the pupil). A clearer example is a camera's aperture http://www.digitalphotographybasics....0/aperture.gif (where there are more 'petals', so that the opening is more nearly circular).'

b