13 replies to this topic

[binocular]

Do they even make them for binoculars?  I'd be interested for my 16x56 Nikon.

[Terra Nova]

Not to my knowledge. There are two types of H-alpha solar filters, one type has the etalon in the front and a blocking filter in the back. These front mounted etalons typically also have an energy rejection filter (ERF) in front of the etalon. They are heavy and expensive and still require an additional blocking filter in the back, ahead of the eyepiece. This is the type made famous by David Lunt who started Coronado. The other type has an ERF in front, over the objective, and a full etalon and blocker in the back. This is like the earlier Daystar filters. These have since been refined to eliminate the need for the front-mounted ERF in small apertures and have everything in the back, ahead of the eyepiece, (the Quark). They all require some form of tuning to stay on band, either by tilting the elements, heating, or modulating the internal pressure. Because of all the parts which need to work together, they are relatively large, complex, and expensive. One other thing to keep in mind is that most of them require a long focal length, (high focal ratio) in order to maintain a very narrow, (approaching parallel) light cone. This is often accomplished by yet another element, a telecentric barlow. Your best bet would be to adapt a binocular telescope, or you could build a binocular from the ground up if you were competent in instrument making. Either way, it will be an expensive proposition, costing several thousand dollars on top of the basic optics. It’s a very different proposition than a mere white-light solar filter.

Edited by Terra Nova, 23 September 2023 - 02:56 PM.

[binocular]

Thanks, it was a stretch but I thought I'd ask just in case someone makes one.  My best option to view the sun then is what I've always been doing and just look at it directly with my eyes before sundown or sunrise!  I still get a kick out of that.

[Terra Nova]

Thanks, it was a stretch but I thought I'd ask just in case someone makes one.  My best option to view the sun then is what I've always been doing and just look at it directly with my eyes before sundown or sunrise!  I still get a kick out of that.

You can always view the sun with binoculars using white light filters over the objective, or buy purpose built solar (white light) binoculars. I have a pair of 8x32 Lunt solar binoculars (Sunoculars), which are great for quick looks any time of the day. They are a lot of fun and enjoy mine a lot. I was using them this morning in fact. They are very modest in cost. Celestron also makes white-light solar binoculars.

[Terra Nova]

https://www.amazon.c...261&sr=8-3&th=1
 

https://www.highpoin...9cab72056022be3

[binocular]

I had a look at those online before but unless I'm missing something, they give off a milky look when viewing don't they?  Was hoping too see the sun with all the colors instead of a whitish glow.

[Spikey131]

One could probably craft an H-alpha binocular telescope with a pair of dedicated solar refractors like the Lunt 40, like others have done with refractors (like here:  https://www.cloudyni...e#entry12924442 ).

 

It is complicated and expensive, but possible.

 

Binoviewers make more sense, because for solar observing, one is going to want to use higher magnification than most binoculars offer.

[gstrumol]

I had a look at those online before but unless I'm missing something, they give off a milky look when viewing don't they?  Was hoping too see the sun with all the colors instead of a whitish glow.

Well the sun is white, and white light has all the spectrum colors in it, so ...

 

Not sure what you mean by 'see the sun with all the colors'? For white light viewing, the only true color of the sun is white. Some glass filters give it an orange hue, and the Baader solar continuum filter makes it green, but these are all false colors.

 

Ha viewing is red, but that's because the Ha line is in the red end of the spectrum. And viewing in Calcium K (CaK) has a purple color as it's in the ultraviolet end. But most people can't see any detail using a CaK filter; in fact, it is recommended only for imaging use.

[Terra Nova]

I had a look at those online before but unless I'm missing something, they give off a milky look when viewing don't they?  Was hoping too see the sun with all the colors instead of a whitish glow.

I don’t see any objectionable milky glow in my Lunts. It’s actually a rather sharp view, just small (only 8X) but given that, and their small size and light weight they are easy to hold steady. If I sit in one of the chairs on my balcony with my elbows braced on the armrests, the view is pretty detailed and quite pleasing.

[Terra Nova]

BTW, I see that the price of the 8x32 Lunt solar binoculars has increased quite a bit. When I bought mine from Amazon year before last, they were $79. Now they’re $129! That’s a fifty-buck increase.

 

Beware, there is a much cheaper model. Perhaps that’s the one that produces the inferior images you mention.

[Sebastian_Sajaroff]

Be careful, don’t confuse Hα filters that you thread inside the eyepiece to observe nebulae with the Hα filter that comes inside a solar telescope.
You can’t swap them.
If you use a nebulae Hα filter to observe the Sun, it will crack under heat and burn your eye.
If you point a solar telescope to a nebula you see nothing, filter is too narrow.
The best way to observe the Sun with both eyes is to plug a binoviewer, remember it splits 50% light to each eye so the view will be dimmer than on one eye only.

[Terra Nova]

Be careful, don’t confuse Hα filters that you thread inside the eyepiece to observe nebulae with the Hα filter that comes inside a solar telescope.
You can’t swap them.
If you use a nebulae Hα filter to observe the Sun, it will crack under heat and burn your eye.
If you point a solar telescope to a nebula you see nothing, filter is too narrow.
The best way to observe the Sun with both eyes is to plug a binoviewer, remember it splits 50% light to each eye so the view will be dimmer than on one eye only.

If you use such a filter (a narrow band, night-time astronomy filter) to look at the sun, it will burn your eye long before it ever cracks. If you put it in front of the objective, it will never crack, but you will quickly destroy your vision. It’s of utmost importance that you know what you’re doing and only use the right equipment before you ever turn your eyes toward the sun.

Edited by Terra Nova, 23 September 2023 - 04:16 PM.

[binocular]

Well the sun is white, and white light has all the spectrum colors in it, so ...

 

Not sure what you mean by 'see the sun with all the colors'? For white light viewing, the only true color of the sun is white. Some glass filters give it an orange hue, and the Baader solar continuum filter makes it green, but these are all false colors.

 

Ha viewing is red, but that's because the Ha line is in the red end of the spectrum. And viewing in Calcium K (CaK) has a purple color as it's in the ultraviolet end. But most people can't see any detail using a CaK filter; in fact, it is recommended only for imaging use.

I never even new that as when the sun rises it is nice and yellow in the beginning! 

[Terra Nova]

I never even new that as when the sun rises it is nice and yellow in the beginning! 

That’s because of Rayleigh scattering. When the sun is at a very low angle as around sunrise and sunset, the pathrays of the sun travel a longer distance through the lower (denser) atmosphere. Rayleigh scattering occurs when the white light (all wavelengths) of the beam encounters gas molecules. Traveling further through denser air and many more molecules are encountered so a great deal more scattering occurs than when the sun is at a high (midday) angle. Rayleigh scattering Is selective, and blue (shorter) wavelengths are scattered than red (longer) wavelengths, (the amount of Rayleigh scattering is an inverse function of wavelength). Mie scattering (scattering by fine particulates) also come in to play. Again, more particulates are encountered when pathrays are at a low angle. Not only minute dust particles cause Mie scattering but so do tiny ice crystals and wqter droplets. The key is that these types of particles have diameters that approach the wavelength of light scattered, (with Rayleigh scattering, the gas molecules are much smaller). Mie scatter is also selective but the wavelengths scattered approximate the diameters of the scattering particles, and at a low angle, more larger particles are encountered. This turns all of the sky around the light source golden or pinkish or even deep red depending on particle concentrations. Larger particles yet, like large suspended water droplets in clouds and fog, scatter all the wavelengths and turn things grey.