Binoviewer info

[jetstream]

Here is a link to some good info on how binoviewers work, some pretty interesting things going on... any thoughts or comments?

http://www.cloudynights.com/topic/61467-binocular-vision-summation/#entry792719

[YKSE]

That's very long post, it does take up many interesting aspects of binoviewing vs cyclops.

[Peter Drew]

Thanks for the link Gerry. I ploughed through the post but as usual for me, such in depth detail tends to leave my head spinning whereas a number of bottom line conclusions would have nicely informed me. I've had quite a number of years experience with large binocular telescopes and binoviewers and I am positive that two eyed viewing offers several advantages over the single eye. I was glad that the post pointed out that the summation was not the common misconception that 6" + 6" aperture = 12" aperture but just a noticeable improvement over a single objective. It seems obvious to me that if the brain receives two signals instead of one plus noise, the result is bound to be perceived as better as well as the enhanced comfort of using both eyes at the same time.

Dual objective optical instruments tend to be expensive when greater than common sizes, I often contemplate where the difference between dual optics compared to single ones of greater aperture but with a binoviewer makes the latter a more economic consideration.

[jetstream]

I think the OP in the link tried to explain things quite a lot of times, and ended up showing his path to the answers, long may they be. Great to hear first hand that you notice a difference between one eyed and 2 eyed viewing Peter, I noticed differences immediately. The 15" really gave some spectacular views of Jupiter with the binos the other night.

One thing that intrigues me is the exit pupil deal with a beam splitter...the bino gives larger exit pupils but with less light contained in them (?) I wonder if the brain still responds differently to the larger ones or interprets info differently because of this. I'm going to calc my exits with the bino and its equivalent, then play around to see where the limits are. All I know is those galaxies sure popped out, maybe because of the SNR who knows.

So we have : summation, exit pupil changes and signal to noise ratio along with a decrease in effective aperture when using binos- among other things. This and MTF should keep me busy for a while lol!

                   

[YKSE]

I happen to come across this paper:

http://arieotte-binoscopes.nl/Binocular%20Summation%20Factor.pdf

Here's a quote from conclusions there:

"Results shown here indicate that for a binoscope versus a larger-mirrored mono-telescope the binocular summation factor ranges between 1.4 and 1.5. That is: when stars are used as object of observation!!...When extended objects are used as study object, a higher value of the binocular summation factor, between 1.6 and 1.8, is probably more accurate. This traslates to a larger gain in contrast when it comes to observing extended objects with a binoscopes."

[jetstream]

Great info Yong, I noticed the increase in DSO contrast immediately when using the binos. It will be interesting to see how the binos compare on threshold objects... some say cyclops can't be beat- we'll see. The beamsplitter theory seems to hold true with respect to exit pupil, that is that in cyclops my lunar/planetary image starts to dim around 1mm exit pupil and about 2mm with the binos.I'm thinking for filter use I may have to go up near my maximum exit pupil to get them working properly- possibly with 32mm TV plossls. Some playing with different FL eyepieces is in order I think, longer ones from mono viewing...

[Astrobits]

Amongst other explanations I think that there is a physiological aspect.

Throughout our life the brain has had two images to use. It learns quickly to reject a weak signal that appears in only one image but accept it if it appears in both images.

How often do you see the floaters in you eyes during the day? They occur in both eyes but in different places and you only see the most obvious which give the strongest signals. Go to a mono-vision optical instrument and they are readily visible, much to our annoyance.

It is about SNR, Bino-vision works with lower SNR's than Mono-vision.

Nigel