Test for recently bought bins

[Glimmer]

Hi guys:

Following your advices and reading the forum deeply, finally I have purchased one pair of Zeiss Conquest 10x40 bins online.

Which test should I do to ensure that they don't are defective? I´m particularly interested in test collimation (bad aligment of the two barrels).


Thanks!

[g8ina]

There are (usually) two things that can go wrong - either the lenses are not right or the prisms. Usually, it's the prisms that we can adjust, see http://www.cloudynights.com/item.php?item_id=416.

Lenses out of alignment is much trickier, esp if it's a sealed unit. Once you've assured yourself that the prisms are OK (that both eyes are looking in the same direction basically) an easy test is a star test. Just take them out tonight and focus on a bright star, it should come into focus as a circle, coming down to a point. If there is a flare to one side this may be due to misalignment of the lenses (it's called coma).

Zeiss has a pretty good name, so I would be fairly confident that they will be OK, but it's easy to check.

hth

[Glimmer]

There are (usually) two things that can go wrong - either the lenses are not right or the prisms. Usually, it's the prisms that we can adjust, see http://www.cloudynights.com/item.php?item_id=416.

Lenses out of alignment is much trickier, esp if it's a sealed unit. Once you've assured yourself that the prisms are OK (that both eyes are looking in the same direction basically) an easy test is a star test. Just take them out tonight and focus on a bright star, it should come into focus as a circle, coming down to a point. If there is a flare to one side this may be due to misalignment of the lenses (it's called coma).

Zeiss has a pretty good name, so I would be fairly confident that they will be OK, but it's easy to check.

hth

Many thanks! I'll try to do the star test tonight.

I'm not enough courageous to adjust the prisms! But however I'll check the exit pupils...

[stuart C smith]

Many thanks! I'll try to do the star test tonight.

I'm not enough courageous to adjust the prisms! But however I'll check the exit pupils...

YOU CAN DO A STAR TEST IN DAYLIGHT WITH A BALLBEARING GLUED ON A STICK, IN THE SUNLIGHT.

[g8ina]

eeeehhh, he's good isn't he :) I never thought of that !