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Binocular Solar Filters for Non-Eclipse events

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#1 Cali

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Posted 30 March 2023 - 11:39 AM

Newbie question. What can I see with Solar Filters when viewing Sol, in say, a 15x70 binocular when there is no Solar Eclipse event? Transit of Mercury possible?

 

Thx

-Cal


Edited by Cali, 30 March 2023 - 11:50 AM.


#2 vincentv

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Posted 30 March 2023 - 12:13 PM

Expect to see the photosphere, also called "white light" or continuum.

Here's an image from today: https://spaceweather...r23/hmi1898.gif

That's a relatively low resolution picture. The sun's angular size is about the same as the moon so you can use that a gauge. Every one and then there's a sunspot large enough to be detected without magnification.

 

The level of detail will vary with seeing (can be terrible during the day), holding steadiness, aperture, and magnification.

There are a few threads detailing experiences with the "sunoculars" and other solar binoculars.


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#3 J A VOLK

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Posted 30 March 2023 - 12:24 PM

I use my 10x42s IS with white light solar filters frequently.  I can see medium and larger sunspots, often a large number of spots and groups.  15x and the higher aperture (resolution) should be even better and give very satisfying views.  A tripod or IS will make a very substantial improvement, IMO.



#4 IdahoSkies

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Posted 30 March 2023 - 12:58 PM

This is stating the obvious, but when buying a solar filter, it’s not the time to go bargain hunting.  Get the best you can find to prevent possible eye damage


Edited by IdahoSkies, 30 March 2023 - 01:08 PM.


#5 Cali

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Posted 30 March 2023 - 01:28 PM

 

There are a few threads detailing experiences with the "sunoculars" and other solar binoculars.

 

Where please?

Thx!


Edited by Cali, 30 March 2023 - 07:52 PM.


#6 sevenofnine

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Posted 30 March 2023 - 04:08 PM

Transits are possible with high powered telescopes. Even then it's only a tiny black dot. I'm not sure if you will have enough power at only 15x. Others may comment. This is a good source for quality solar filters.

Good luck! borg.gif

 

https://astrozap.com...t=8277807759404.


Edited by sevenofnine, 30 March 2023 - 04:09 PM.

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#7 Rich V.

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Posted 30 March 2023 - 04:24 PM

I just use a projection method using tripod mounted 10x50s projecting onto a white paper plate.  Much larger image scale and no telescope necessary to see sun spots and transits.

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#8 Sebastian_Sajaroff

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Posted 30 March 2023 - 05:26 PM

Yes, I saw three Mercury transits using 12x50 and 20x50 binoculars, though I used projection on a cardboard (I didn’t have solar filters at the time).
You can see large and medium sunspots with properly filtered binoculars, with 15x70 it gets even better !
Note that the Sun is close to its maximum activity, so it’s the best time to follow sunspots (and aurorae).
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#9 DeanD

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Posted 30 March 2023 - 07:38 PM

Baader produce a range of quality solar observing products. See: https://www.baader-p...m/en/solar.html

I have used their solar film with good results, even in 10x50 binoculars. The film gives a nice, white image, unlike some other visual filters that are quite yellow. You must follow their directions if you use the film so that it is safely and securely attached, and there are no pin-holes in the film! 

 

I saw a transit of Mercury with 10x50's (a very small dot of course!)- and somewhat bigger dot during the last transit of Venus; and you can see sunspots and some faculae on the surface. At higher power you can see the mottled surface caused by convection cells as well: but these are harder to see, and you need to have a bit of patience. You wont see flares around the circumference that you can see with dedicated solar scopes though. I think one of the cheapest of these is the Coronado PST 40: https://www.meade.co...r-telescope.pdp - and this gives surprisingly good images of flares etc. if it is tuned correctly, despite its only 40mm objective.

 

Projection viewing is great, as you can see a much larger image- but I have always used older/cheaper instruments for that (like an old pair of 10x50's, with one side blocked off, or even an old 60mm achromat with a basic kellner eyepiece), as I am not keen on all that heat passing through the lens or eyepieces of my better/more expensive instruments. It is good fun experimenting with what you can use: but again be very careful, and never let it anywhere near your eyes. If you are trying with an old telescope, it is best to find the sun by minimising the shadow of the scope- and (a trap for young players!) make sure you cover the finder scope objective!!!

 

You probably know this already, but just in case: there are some old "solar filters" out there that were designed to place in the eyepiece end of the cheap department store scopes in the 60's and 70's. These are otherwise known as "instant blindness", as the heat can crack them and you can get a magnified image of the unfiltered sun straight into your eye. Never, ever use one of these: the best thing to do with them is treat them harshly with a hammer (so no-one else can use them) and put in the rubbish. The same goes for using welding glass. 

 

The solar filters produced by Baader, Astrozap etc. always cover the front or objective lens, and reject most of the heat energy.

 

Good luck, and have fun.

 

- Dean


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#10 aznuge

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Posted 31 March 2023 - 06:17 PM

Great advice above^^!  I cut my teeth on solar observing with Maven 15x56 Binoculars and 82mm BTs.  I use a different type of solar filter with each of these.  With the Maven I use a 58mm camera lens type that threads into the objective housings.  With the Kowa 82mm BT I use the "press-fit" type that goes over the objective housings like caps. Both work great.  I obtained the camera lens type from Thousand Oaks Optical, and the ones for the BTs from Spectrum Telescope.  I have since added other solar filters of both types, so that I can do solar observing with 10x binoculars up to 100mm BTs.  Good luck with your solar observing pursuits.  To me it is a fascinating aspect of astronomy.

 

sml_gallery_347100_17026_50720.jpg   sml_gallery_347100_17026_9384.jpg



#11 Cali

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Posted 01 April 2023 - 02:04 AM

I just use a projection method using tripod mounted 10x50s projecting onto a white paper plate.  Much larger image scale and no telescope necessary to see sun spots and transits.

Please elaborate. How can I make one.

 

- Cal



#12 Cali

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Posted 01 April 2023 - 05:27 AM

Yes, I saw three Mercury transits using 12x50 and 20x50 binoculars, though I used projection on a cardboard (I didn’t have solar filters at the time).
You can see large and medium sunspots with properly filtered binoculars, with 15x70 it gets even better !
Note that the Sun is close to its maximum activity, so it’s the best time to follow sunspots (and aurorae).

How does one construct such a device?



#13 Rich V.

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Posted 01 April 2023 - 10:03 AM

Please elaborate. How can I make one.

 

- Cal

I showed a picture of my simple binocular mount setup in post #7.  I cut a hole in a large shoe box lid for one objective lens to stick through.  It's held on with a bit or two of gaffer's tape.  The box lid creates a large enough shadow to shade the paper plate so the image of the sun that's projected from the eyepiece shows up brightly.  If you have two tripods handy, use the second one to affix the plate onto.  As long as the plate is held square to the binos, and back away a couple of feet, plus or minus a bit, you should get an ample sized projected image.  The image shown is about 5" in diameter.  Carefully focus the binos for the sharpest image.  

 

I've watched transits, eclipses and just viewed sunspots this way for a number of years.  Easy to share with others.

 

I've felt the temperature of the bino's eyepiece and it doesn't seem to get very warm at all, but the advice above not to use your best binos is probably a good idea, if you're worried about it.  wink.gif

 

Rich


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#14 Sebastian_Sajaroff

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Posted 01 April 2023 - 10:31 AM

How does one construct such a device?

Basic solution : just need a piece of cardboard.

Better solution : mount the binoculars on a tripod

 

 

 

binocularprojection2.gif

https://images.app.g...E6A37mhHt15wf68


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#15 SporadicGazer

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Posted 03 May 2023 - 10:18 AM

I just wandered into this sub-forum, you folk are going to cost me money!  Especially this thread.

 

One thing I can add, is about this:

 

 ....  I think one of the cheapest of these is the Coronado PST 40: https://www.meade.co...r-telescope.pdp - and this gives surprisingly good images of flares etc. if it is tuned correctly, despite its only 40mm objective. ...

is *IF* you can find one in stock the Lunt 40mm Solar Scope lists, starting at $750 (https://luntsolarsys...olar-telescope/) and seems to be held in higher regard these days.  (Sadly Lunt production seems really backed up and as we approach a solar maximum with two USA Eclipses coming up, it'll probably be a while before they catch up.)



#16 Terra Nova

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Posted 27 May 2023 - 09:21 AM

Great advice above^^!  I cut my teeth on solar observing with Maven 15x56 Binoculars and 82mm BTs.  I use a different type of solar filter with each of these.  With the Maven I use a 58mm camera lens type that threads into the objective housings.  With the Kowa 82mm BT I use the "press-fit" type that goes over the objective housings like caps. Both work great.  I obtained the camera lens type from Thousand Oaks Optical, and the ones for the BTs from Spectrum Telescope.  I have since added other solar filters of both types, so that I can do solar observing with 10x binoculars up to 100mm BTs.  Good luck with your solar observing pursuits.  To me it is a fascinating aspect of astronomy.

 

sml_gallery_347100_17026_50720.jpg   sml_gallery_347100_17026_9384.jpg

I’m always looking for easy viewing alternatives for my condo’s east-facing balcony and am considering getting a set of white light solar filters for my Maven C4 18x56 EDs. Any recommendations? I just ran across these:

https://astrozap.com...ss-solar-filter

 

(I have the Lunt 8x32 Sunoculars which are fun, but considering their size, I consider them more a ‘scout’ solar instrument to tell me whether to haul out the big guns.)


Edited by Terra Nova, 27 May 2023 - 09:25 AM.

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#17 B 26354

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Posted 27 May 2023 - 12:51 PM

I’m always looking for easy viewing alternatives for my condo’s east-facing balcony and am considering getting a set of white light solar filters for my Maven C4 18x56 EDs. Any recommendations? I just ran across these:

https://astrozap.com...ss-solar-filter

 

(I have the Lunt 8x32 Sunoculars which are fun, but considering their size, I consider them more a ‘scout’ solar instrument to tell me whether to haul out the big guns.)

Terra,

 

I have white-light solar filters for my 60, 70, and 100mm binoculars.

 

For the 15x60s:

 

https://agenaastro.c...er-asbf-60.html

 

Baader solar filters on Docter 15x60 b.jpg

 

 

For the 20x70s:

 

 

https://www.bhphotov...ens_filter.html

 

 

 

For the 25x100s:

 

https://www.highpoin...lescopes-az1001

 

APMs & Solar Filters 1b.jpg

 

 

Another inexpensive option is the Rainbow Symphony line of solar filters (same filter material as in their cardboard eclipse-glasses) and which come in 50, 60, 70, 76 and 101mm sizes:

 

https://milehighastr...=30385660624989

 

 

I very much like the construction of the Baader AstroSolar Filters that I use for the 15x60s, and I used the telescope version with my ES102CF:

 

https://www.highpoin...-filter-astf100

 

...to take this photo of the (partial, for me) 2017 solar eclipse:

 

8-21-17 Partial C.jpg

 

 

All of these white-light filters are perfectly safe, and very easy to use... but when contemplating using them with large-aperture (56mm) roof-prism binoculars, a critically-important factor to consider, is whether or not the filter housings will be too large in diameter to be able to slip onto the the binoculars' OTAs when the binoculars are adjusted for your specific IPD. And this is important whether your binocs utilize Schmidt-Pechan prisms -- as do the Maven C4 18x56s -- or the less-commonly used Abbe-Koenig prisms, which generally allow for a wider separation between the objective lenses.

 

In my case, with a relatively narrow 58.5mm IPD -- and because of their use of Schmidt-Pechan prisms -- in order to use my 10x56 and 12x56 binocs, I have to push them completely together, such that the OTAs are touching. Consequently... none of the above "slip-on" solar filters will work. My 8x56s utilize Abbe-Koenig prisms, and when they are adjusted for my IPD, there is a 7mm separation between the OTA housings... but that's still not enough clearance to allow me to use any of the above solar-filter sets.

 

In your case, I searched online, but was unable to find a website that listed the IPD range for the Maven C4 18x56 EDs... nor was I able to determine whether or not they have provision for objective-lens screw-in filters. But before purchasing any solar filters, I would definitely set your Mavens to your IPD, and then measure the amount of clearance there is between the OTAs.

 

Hope this is helpful.

 

biggrin.png


Edited by B 26354, 27 May 2023 - 12:56 PM.

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#18 aznuge

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Posted 27 May 2023 - 02:12 PM

I’m always looking for easy viewing alternatives for my condo’s east-facing balcony and am considering getting a set of white light solar filters for my Maven C4 18x56 EDs. Any recommendations? I just ran across these:

https://astrozap.com...ss-solar-filter

 

(I have the Lunt 8x32 Sunoculars which are fun, but considering their size, I consider them more a ‘scout’ solar instrument to tell me whether to haul out the big guns.)

Not sure in the Maven C4s have the threaded objective housing like the Maven B5s do.  But if they do, its hard to beat the 58mm thread in solar filters like these.  For the slip-ons, IPD may be a consideration as B 26354 points out.  Also glass vs thin film material - I've never used the glass ones, but they should be good, only a bit heavier.


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#19 edwincjones

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Posted 28 May 2023 - 05:07 AM

With my Lunt 8x32 Sunoculars I saw 5 sunspots this week-a record for the Lunt.  I got these for the upcoming total eclipse in 2024.

 

In the past I have used a 10x70 and seen more --which I would consider the smallest for more serious solar viewing

 

You really need a telescope for its higher resolving power.

I use the solar image on space weather.com as a comparison.

 

edj


Edited by edwincjones, 28 May 2023 - 05:09 AM.

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#20 edwincjones

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Posted 28 May 2023 - 05:19 AM


"All of these white-light filters are perfectly safe, and very easy to use..."

 

 

question.gif 

 

I would not say "perfectly safe" but more relative safe

The filters can fall off, the mylar can develop holes, the glass can break.

A brief lapse in attention can cause much damage.

 

edj


Edited by edwincjones, 28 May 2023 - 05:20 AM.


#21 Terra Nova

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Posted 28 May 2023 - 08:28 AM

With my Lunt 8x32 Sunoculars I saw 5 sunspots this week-a record for the Lunt.  I got these for the upcoming total eclipse in 2024.

 

In the past I have used a 10x70 and seen more --which I would consider the smallest for more serious solar viewing

 

You really need a telescope for its higher resolving power.

I use the solar image on space weather.com as a comparison.

 

edj

That’s what I use the Sunoculars for; to tell me whether it’s worthwhile to set up one or more of my telescopes. I have a variety of glass and mylar over-ap filters of different sizes for them as well as a wedge, plus H-alpha and Ca-K options. Long time solar observer here as well. My favorite solar ap is the SoHO Viewer for iOS.


Edited by Terra Nova, 28 May 2023 - 08:32 AM.


#22 Terra Nova

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Posted 28 May 2023 - 10:05 AM

Terra,

 

I have white-light solar filters for my 60, 70, and 100mm binoculars.

 

For the 15x60s:

 

https://agenaastro.c...er-asbf-60.html

 

attachicon.gifBaader solar filters on Docter 15x60 b.jpg

 

 

For the 20x70s:

 

 

https://www.bhphotov...ens_filter.html

 

 

 

For the 25x100s:

 

https://www.highpoin...lescopes-az1001

 

attachicon.gifAPMs & Solar Filters 1b.jpg

 

 

Another inexpensive option is the Rainbow Symphony line of solar filters (same filter material as in their cardboard eclipse-glasses) and which come in 50, 60, 70, 76 and 101mm sizes:

 

https://milehighastr...=30385660624989

 

 

I very much like the construction of the Baader AstroSolar Filters that I use for the 15x60s, and I used the telescope version with my ES102CF:

 

https://www.highpoin...-filter-astf100

 

...to take this photo of the (partial, for me) 2017 solar eclipse:

 

attachicon.gif8-21-17 Partial C.jpg

 

 

All of these white-light filters are perfectly safe, and very easy to use... but when contemplating using them with large-aperture (56mm) roof-prism binoculars, a critically-important factor to consider, is whether or not the filter housings will be too large in diameter to be able to slip onto the the binoculars' OTAs when the binoculars are adjusted for your specific IPD. And this is important whether your binocs utilize Schmidt-Pechan prisms -- as do the Maven C4 18x56s -- or the less-commonly used Abbe-Koenig prisms, which generally allow for a wider separation between the objective lenses.

 

In my case, with a relatively narrow 58.5mm IPD -- and because of their use of Schmidt-Pechan prisms -- in order to use my 10x56 and 12x56 binocs, I have to push them completely together, such that the OTAs are touching. Consequently... none of the above "slip-on" solar filters will work. My 8x56s utilize Abbe-Koenig prisms, and when they are adjusted for my IPD, there is a 7mm separation between the OTA housings... but that's still not enough clearance to allow me to use any of the above solar-filter sets.

 

In your case, I searched online, but was unable to find a website that listed the IPD range for the Maven C4 18x56 EDs... nor was I able to determine whether or not they have provision for objective-lens screw-in filters. But before purchasing any solar filters, I would definitely set your Mavens to your IPD, and then measure the amount of clearance there is between the OTAs.

 

Hope this is helpful.

 

biggrin.png

Great advice Thank you. I’ve checked the I.P. distance and it would be tight. I think it’s probably not the best idea for my Mavens.  


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#23 B 26354

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Posted 28 May 2023 - 10:14 AM

"All of these white-light filters are perfectly safe, and very easy to use..."

 

 

question.gif

 

I would not say "perfectly safe" but more relative safe

The filters can fall off, the mylar can develop holes, the glass can break.

A brief lapse in attention can cause much damage.

 

edj

Thanks, edj. My answer was addressed specifically to Terra, who is a scientist, and a highly-experienced stellar and solar astronomical observer... so I didn't feel the need to explain the rudimentary safety precautions that one needs to practice when observing the sun.

 

biggrin.png


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#24 B 26354

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Posted 28 May 2023 - 10:19 AM

Great advice Thank you. I’ve checked the I.P. distance and it would be tight. I think it’s probably not the best idea for my Mavens.  

Thanks Terra. Per aznuge's speculation... do the C4 18x56s have filter threads on the objective lenses?


Edited by B 26354, 28 May 2023 - 10:20 AM.


#25 Terra Nova

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Posted 28 May 2023 - 10:35 AM

Thanks Terra. Per aznuge's speculation... do the C4 18x56s have filter threads on the objective lenses?

There is a threaded ring above the objective and below the rubber end ring. It looks tight tho. I don’t think I would want to try and thread a filter in there. I’m now thinking of getting a 70mm BT. I could always add a pair of solar filters, but then again, if I’m going to do that, I might as well just set up a telescope.


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