4x21 Xtrawide. (2 Viewers)

[Binastro]

Used Bushnell 4x21 Xtrawide binocular to view Mars and Jupiter.

Both looked beautiful in the same field at 3.30 a.m.

Slightly too far apart for Dowling and Rowe 4x22.

I estimated the separation as 16.7 degrees.

Both were in focus for me as the curved field means that towards the edge both planets were in focus.
The binocular is fixed focus.

Regards,
B.

 

[Gijs van Ginkel]

Binastro, post 1,
Just for fun we have investigated a number of ultrawide binoculars (test is published on the WEB-site of House of Outdoor) and the Bushnell Ultrawide 4x21 was one of them. A strong competitor in the same price range (30- euros) was the Libra 4x22 with the same FOV of 300m/1000m and for about 25 euros about half the price of the Bushnell, it has even a higher light transmission around 62% versus 54% for the Bushnell.. The Bushnell has a measured magnification of 3,4x and the Libra 3,9x. Both binoculars are kind of special.
Gijs van Ginkel

 

[Binastro]

Hi Gijs,

I estimated the magnification of the Xtrawide as 3.5x and the Libra (Dowling and Rowe) as 4.0x.
I am pleased you actually measured them both.

However, as I am far sighted maybe my estimates are correct for me.

I measured the Xtrawide field as 18.5 degrees and the Libra as 16.5 degrees with an easy 16.3 degrees.
Using star separations.

I also used the 5x25 VisionKing.
I estimated the field of this as 14.8 degrees and variously up to 15.4 degrees depending on how close I got and changing the IPD.
They claim 15.8 degrees, which could be possible.
Hand holding fields are wider because of hand movement and persistence of vision.

There was also a nice display of noctilucent cloud this morning from 2.48 a.m. when I first spotted them.

Regards,
B.

 

[Binastro]

The actual angular separation of Mars and Jupiter was 16.5 degrees, so I was over 1% out.

16.5 degrees is what I got using Pythagoras as both planets were near the celestial equator, and spherical geometry wasn't strictly necessary.

Not too bad, I suppose.

Regards,
B.

 

[pat mitchel]

I simply HAD to break into my shop goodwill 4x21's to see if I could adjust for use without glasses- yeah, it's a pain in the backside to make the adjustment back and forth - it's doable just no fun. Ultimately put them back to infinity at 20-20 vision. For me, living in a bright city- no win to use something like that anyway- sigh! Pat

 

[Binastro]

Hi Pat,

For me the Xtrawide 4x21 is not fun either, but it has limited use as above.

Children seem to like them.

The accuracy achievable with binoculars as measuring instruments isn't great, but useful.

Consumer laser rangefinders are also only accurate to about 1%.

In many cases GPS is worse.

Regards,
B.