Calling amateur collimators !

[solentbirder]

My father has a pair of 7x50 porro prism bins that are slightly out of collimation (enough to be annoying). They're worth very little money and he doesn't want to pay for them to be re-collimated. I said I'd do it for him, expecting that the objectives would be mounted in eccentric rings (making it a 10 minute job). However, the objective mounts seem to be symetrical. The prism housings have a soft vinyl covering and I can't see any obvious positions for collimating screws. Any advice out there ?
Many thanks
John

[henry link]

John,

See this article at Cloudy Nights: http://www.cloudynights.com/item.php?item_id=416

[solentbirder]

Many thanks Henry. I had a look at the article and was able to locate the collimation screws. I only had to make a small adjustment to one screw and things are back to normal.
B (: