William Optics Barlows?.

[Alan White]

William Optics make a 1.6x Barlow for the bino-viewer but also a 2x as well, they look very alike.

Simple question, without looking through them, how do you tell them apart as they have no labels?

[Franklin]

As far as I'm aware, the 1.6x is supplied with the WO binoviewer set and the 2x is available seperately. They do look very similar though?

[Elp]

The 1.6x is supplied with the binos

[Alan White]

You are indeed both correct,
but if you don’t have the binos new, how do you tell them apart? 

It’s the identity after purchase that I am asking about, are the differing in length or something perhaps?

Perhaps a question for @FLO via email

Edited June 7 by Alan White

[Star Struck]

They are different sizes. One is clearly deeper than the other.

I used to own both but cannot remember which was the deepest.

[great_bear]

I have both of them.

I have no trouble telling them apart - they are different lengths for one thing - the 2x being the shorter one, but the main difference is that if you hold them up in front of your face a few inches away and look at (e.g.) some nearby trees, the 2x will have the wider view. 
 

If you are in the dark and want to know which one you have in your hand, with experience you can hold it up to the sky and tell by the aperture which one it is - the 2x having the larger aperture by some margin. 

Edited June 19 by great_bear

[Alan White]

Jeremy @great_bear
Thank you.

Could you please measure the legths for me, as I am unsure that both my ones are WO,
One certainly is, but I am unsure.
Your help would be very much appreciated and informative for other looking at this thread in time to come.

[Peter Drew]

An easy way to determine the focal length of a Barlow lens is to draw a circle to twice the size of the lens and then focus the Sun  through it.  Draw the lens away until the image fills the circle and the distance between the lens and the image is the focal length.  Perhaps not so easy in the UK!       

[great_bear]

8 minutes ago, Alan White said:

Could you please measure the legths for me, as I am unsure that both my ones are WO

Sure - will do so later today. 

[great_bear]

33 minutes ago, Alan White said:

please measure the lengths for me

As per photos below:

 

You can tell it's a William Optics product - it hasn't been baffled properly! (see above photo)

[Don Pensack]

Easy enough on those to take them apart and blacken lens edges and spacers.

[Alan White]

Thanks all for the information, this means I need the 2x to get focus with the scope.
So I can now work out the magnifications being used, I hope.
 

 

[great_bear]

5 hours ago, Alan White said:

I can now work out the magnifications being used.

Will you do this be by coomparing (e.g.) star distances with a known eyepiece?

That's what I had to do with my Mak + binoviewer. The mirror shift required for a revised focal plane that includes the binoviewer, changes the magnification on a mak. in a manner that I knew would be tough to calculate, so I recorded the change in spacing between specific stars.

On my Mak180 this gives me:

• Bino + eyepieces:                1.20 x mono (normal) eyepiece magnification
• With 1.6x barlow on bino:   1.75 x mono eyepiece magnification
• With 2.0x barlow on bino:   2.12 x mono eyepiece magnification

- although of course on any telescope I would assume that non-parfocal eyepieces would get some slight variance in magnification when using a regular, i.e. non-telecentric, barlow, so I'd always use measurement to get the answer.

I wonder what level of magnification the William Optics Bino Barlows provide if screwed directly on the base of an eyepiece, rather than on the binoviewer nosepiece.

Anyone know?

 

Edited June 21 by great_bear