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I think solar binos would be fun, any recommendations? (1 Viewer)

JasIA

Well-known member
A brief internet search brought up a couple of options but does anyone have experience with solar binos? Maybe something around $100 or less. Nothing fancy.
 
Be very careful indeed.
The only ones I would say are O.K. are the Coronado special solar binoculars 10x25 if still sold.

I personally know people with permanent eye damage from home made or poor solar optics.

Basically, never look at the Sun with optical aid or with your unaided eyes.
And if you do solar observing make sure you know what you are doing.

Join a local astronomy club.

Unfortunately I anticipate several hundred people getting permanent eye damage from the forthcoming U.S. solar eclipse.
But its not my continent and it is up to the U.S. astronomers and authorities to advise.

P.S.
B and H say Coronado 10x25 solar binoculars are no longer available.
I would not buy them secondhand.
I would advise against using any so called solar binoculars unless they pass the most stringent tests by people experienced with solar observing.


Projecting the Sun onto white card with 10x25 binoculars is O.K. But never look through them at the Sun. Permanent eye damage will result.
 
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You might go to local source of welding supplies. Look into getting a replacement view plate for an arc welding helmet. You might need two of these plates. These are just rectangular pieces of glass very heavily tinted that shield the welder's eyes from the sun bright electric arc of the welder. With a bit of tinkering these can be temporarily fastened to the objective end of the binocular.

A welder's helmet was what was recommended for eclipse viewing back when I was in school.

You might find something similar with a google search.
https://www.amazon.com/s/?ie=UTF8&k...s&tag=googhydr-20&index=aps&hvadid=1772659345

Heed what Binastro told you.
 
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Steve.
The only welders glass considered safe is a certificated shade 14.
Shade 14 are difficult to come by in Britain. Sometimes a shade 15 is needed, but I don't even know if these are available.
It should have an etched BSI or equivalent marking. If only surface printed I put clear tape over it.
In Britain because of pollution I use a large size shade 13 that I can tilt to get the correct density.

I have been a solar observer for well over 50 years. I maintain strict safety rules.

Solar observing and Fun are not words to be used together.
It is no fun living the rest of ones life with permanent eye damage.

The Sun is half a million times too bright for direct viewing with the unaided eyes. Permanent damage can occur from one to maybe 11 seconds with clear skies.
Antibiotics and some other medications make one more vulnerable.

If one has had eye surgery the eye doctor must be consulted.

Invisible UV, invisible infrared and visible light, especially near blue are all dangerous.

Using optical aid eye damage can be instant.

There have been fake filters and we have had long battles to get these withdrawn.
Generally Solar astronomers and eye surgeons have the experience to advise. Also the Royal Astronomical Society and equivalent bodies.

The safe visual filters reduce the intensity 100,000 times through the whole spectrum. Even here there are time limits.
Photographic solar filters are inadequate as they are less dense.

Newspaper articles are not reliable.

This is vast subject, and really only safe projection is recommended.
 
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BINASTRO said: "Newspaper articles are not reliable."

But, there's no way to say that accurately on the forum. We can't use 72pt, multi-colored, flashing text!

From der overdue "crankipuss" book:


A Story: In early September 2015, someone in Orlando, Florida lost possession of his pet king cobra, “Elvis.” In October the 8-foot snake was captured hiding under a clothes dryer and certain people in the local media, including one television newscaster, announced the “kingsnake” had been found.

Although comparing a large, deadly king cobra to a small, non-poisonous kingsnake is like comparing a new Rolls-Royce to a used Volkswagen beetle, all those inexperienced or cranially challenged announcers and editors had the power to influence the unwary. And if such easy to find information can be that misunderstood and handled so carelessly by those we have come to trust, how much easier would it be for busy magazine writers and editors to misconstrue a topic as foreign to most as binocular optics? :cat:
 
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Ed,
The problem is that some ready made solar filters may be, and are in fact, fake.
We tested some in a world class university laboratory that transmitted up to 27% of the infra red.
It took us years to get them stopped.

And if genuine, then they have to be mounted most securely.
Mounting filters on binoculars is difficult.

One needs to go to a dedicated source such as the Royal Astronomical Society or the equivalent U.S. body.

If one does not have such correct advice, then I repeat, the safest way is by safe projection.
 
Some years back, I bought a sheet of flexible solar filter material made by a company called Baader Planetarium. This stuff is cheap and effective in my experience. I plan to visit Nebraska for this summer's eclipse armed with it. Here is what I have done with it in the past.

I made an opaque cover to fit over the end of my 10" Dob scope, and cut a 2" hole in it which I covered with the shiny plastic sheet material. That gives about all the resolution needed for observing in the turbulent daytime air. I found the view just a tad bright, and wore sunglasses for a completely comfortable view. The image is slightly blue but that doesn't bother me. I used the scope at 50 to 100x, or exit pupils of 1mm or less, and the detailed views of sunspots were enjoyable.

I covered the objectives of a 10x50 binocular with this stuff to view the transit of Venus a few years ago. Because of the binocular's much larger exit pupil area, I decided to use the material double thick. I used rubber bands to hold the stuff onto the binocular. The view in this case was a bit on the dim side but acceptable, and I shared the view with my work mates.

The stuff does seem fragile, but try to rip it and see how you do with that. It is thin and wrinkly, but the reflective layer is so thin (Less than 1/4 wavelength) and the index of the plastic upon which it is applied so low, that it doesn't need to be flat to give a good image.

Ron
 
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Hi Ron.
The Baader Planetarium material is an established brand. Visual material, not photographic, which is less dense.

However, check if it has a 5 year recommended lifetime.

The material should not be stretched.
It should be checked for pinholes with a 60 watt bulb.

An infra red TV remote gives a rough check.
If you can turn the T.V. on or off or use any functions at 3 feet the material is not safe.
I need to get down to less than 1 foot to change anything on the T.V. with safe filters.

I am surprised one can see anything through a double layer.

Using sunglasses usually expands ones pupils. Not so good.

A friend used a filter made from I think 8 sunglasses lenses on a small telescope, maybe 25mm aperture when he was eleven. He instantly had permanent eye damage in one eye. Unfortunately this great observer passed away recently very young. Heart problems. Nothing to do with optics.

People need to take care and go to established sources.

P.S.
Opaque material may not be in infrared.
The black bodied plastic Pentax 110 cameras let through radiation and fogged film.

Old rubber bands snap.
 
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Hi,

Baader filter for VISUAL is safe and recommended. Make sure that it has no pinholes as described above and mount it safely.

A good idea is to make a tube from card board to slip over the objective barrel firmly glued to two pieces of cardboard with a hole of the aperture and the film glued between those.

Please overengineer it so it can't be torn apart by wind and secure each cardboard tube with a piece of duct tape or two to the objective barrels.

Joachim
 
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Binastro,
I appreciate your warnings.

I shared, initially, your puzzlement that such an extreme degree of attenuation as provided by the Baader film could be doubled, in going from exit pupil size of 1 to 5 mm, only a factor of 25 in illumination, and still be useful.
I think the solution lies in the fact that visually, 1mm pupil with 1 layer appears uncomfortably bright, while 5mm pupil with 2 layer appears almost too dim. Thanks to the eye's logarithmic response, something like a million in illumination intensity range is visible. That takes up a lot of slack here.

Ron
 
Hi Ron,
I can think of at least two reasons.
Los Alamos is at about 7,320 ft and I suppose the air is very transparent.

I have used different shades.
Some of the free resin? filters were shade 15.5, which is too dark in a polluted city but maybe O.K. in a rural site.
It may be that Los Alamos needs shade 16.

The Baader Planetarium material that you use may be a dense photo material rather than visual. I think they made various shades.

Doubling up I could see no filament of a clear 60 watt tungsten bulb with welders shades 13 or 14, which bulb I still have.
With a safe filter visually the filament is seen but rather dimly with one safe filter.

As to lifetime.
Eclipse shades or eclipse glasses usually state 5 years and some have very nice details of exposures. Say one minute every ten minutes or something similar.
Generally exposures should be rather short.

Organic materials, and I don't know which are, probably deteriorate over time.

I think that a glass, certified welders glass, has a very long life, but I don't know what it is.
Stained glass windows have lasted centuries. But glass does devitrify, maybe depending how it was made and what it contains.

There are numerous available shades and glasses on the internet, but I would only go with established known makes and ones that have honest certified marks. But we know fake marks are numerous, so people should be careful.
Buying cheaply is rather silly when ones eyesight is at risk.

Projection is still the safest way when done correctly.

As to opaque material covering a large scope, with a small window of eclipse material, I would avoid plastics as these may transmit infra red.
I suppose that metal is O.K.
 
Phillips Safety Products has a good description of eclipse safety glasses.

'High quality glasses for viewing a solar eclipse' Sept 1st 2016 by Mayura Satghare is I think a good article.

Of course I only suggest this for reading and have no knowledge of their products.

The spacesuit visor by NASA for the space station is covered with a layer of gold and offers filtration beyond that of a #14 welder's helmet.

Thin layers of chromium alloy or aluminium are used on quality glasses.

Plastics can be damaged by handling etc.

Separately I see that Resins may lose filtration over time.

The 7th root of one thousand is I think 2.683 and is I think the difference between welder's glass shades.
This seems the most bizarre multiple in common use.
 
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