Should I get binoviewers?

[John]

My TMB/LZOS 130 refractor is "binoviewer ready" and has an extension section that can be retracted to allow binoviewers to come to focus without the need for an amplifier / barlow / etc:

[johninderby]

I have to correct you there. I have tried a number of binoviewers on some very fine scopes and despite being “optimised” still prefered the one eyed observing. And it’s not just me. Many very experienced observers have found they don't like binoviewers. It’s just a matter of personal preference that’s all.

They may work for you but not for everyone. Peoples eyesight does differ so you can’t make the sweeping assumption that your opinion is correct for everyone..

Edited November 16, 2019 by johninderby

[Space Hopper]

1 hour ago, johninderby said:

I have to correct you there. I have tried a number of binoviewers on some very fine scopes and despite being “optimised” still prefered the one eyed observing. And it’s not just me. Many very experienced observers have found they don't like binoviewers. It’s just a matter of personal preference that’s all.

They may work for you but not for everyone. Peoples eyesight does differ so you can’t make the sweeping assumption that your opinion is correct for everyone..

I don't John.

As i said earlier :

Quote  "But thats just my own £0.02p on the subject, and i appreciate that others don't necessarily agree with me."

I will end it there thankyou.

[Paz]

10 hours ago, mikeDnight said:

Hi Paz,

Using the Tak 1.25" back can be problematic, in that the compression ring needs to be overtightened to prevent the binoviewer from gradually slipping under its own weight.  To overcome the problem I use a Skywatcher 2" to 1.25" low profile adapter in a Takahashi 2" back. It is a brilliant little device that grips the diagonal like a vice, and also allows me to rotate the back end without unscrewing anything. By releasing one of the two locking screws I can move the angle of the binoviewer with ease.

The collimation issue you mentioned could simply be the locking screws on the binoviewer pushing the eyepieces slightly off axis. With my binoviewer for example, if I put the locking screws on the outside edge of the eyepiece holders the image will never merge. But if the screws are screwed into the holes between the eyepiece holders, the images merge perfectly. This may be due to less than perfect engineering. Also, I never focus rotating the diopter adjustment. Instead I've wound the diopters close to their inward setting, then after focusing the scope I retract one of the eyepieces until both images are perfectly focused, then lock the retracted eyepiece in position (its only about a millimetre difference). It sounds complex but its really quite simple. Once you've found your perfect setting its probably wise not to allow others to adjust the diopters, as this will throw the whole thing out and it can take a while to re-set it to your own preference. 

Oh, the little Tak prism is as tough as old boot. Mine has taken a real hammering over the years and is still going strong. ☺

Thanks for posting this, it is really useful.

[Rob Sellent]

I've been out practicing almost everynight with the binoviewers I purchased a couple of weeks back. The set up has been an unbranded binoviewer, 1.6x GPS, Mark IV zooms, Tak 1.25" diagonal and a 2" to 1.25" TS twist-lock adapter to keep everything from slipping.

Jupiter and Saturn (and Mars) are no longer visible at the hours I can observe and I've only been concentrating on the Sun and Moon. Over the next 2 weeks as the skies darken further, I'll try deep space.

So far I've found:

• H-alpha solar 60mm B1200 - exceptional surface detail of the chromosphere; prominences lose clarity and detail, along with spicule features around the limb.
• White Light Herschel Wedge - to date there has been very little activity but the view is very nice. I'm sure the binoviewers will come in handy as solar minimum draws to an end.
• Lunar - surface detail and contrast is excellent. Viewing for extended periods whilst sketching is significantly more comforting with binoviewers. 

Technically, I've found:

• longer focal lengths are easier to merge and observe with. As such, I feel it is better to optain magnification with Barlows or a GPS, rather than shorter length eyepieces.
• I haven't noticed any significant drop in resolution or brightness (only looking at the Sun and Moon, after all!)
• more faffing is required with binos and they add weight to the set up.
• the narrower field of view still feels very immersive.
• tricks of the brain, visual summation and improved acuity wih the two eye use makes it easier to see detail at lower powers.

Should one purchase binoviewers? I think one can only decide this by trying them and then sharing their experiences on SGL to help inform and educate others. For good or bad, that's the only way one will be able to answer the question for themselves. 

Edited November 17, 2019 by Rob Sellent