7 x 50 or 10 x 42 Best Binoculars To View Solar Eclipse?

[dduelin]

No, I'm not using binoculars to LOOK at the sun. I'll be using them to project the image of the eclipse onto a white screen at ground level. From my boating days I have a pair of 7 x 50s of pretty good quality and a pair of 10 x 42s. They will be mounted on a tripod with the image focused downwards onto a white piece of cardboard for the screen. I'm not sure which pair would be better to use for the eclipse. I remember the Fujinon 7 x 50s were of better quality when new so I assume the image will be clearer.

Anybody with knowledge in optics to comment?

The binoculars will be fixed to the aluminum plate on top of the tripod in the picture. https://www.timeanddate.com/eclipse/binoculars-telescope-projector.html

 

[the Ferret]

interesting set up Dave. Then you take pics of the white screen on the ground?

 

[Roger]

Got to remember that the image on a white screen is going to get hot as you get set up! I've seen a projection onto water in a bucket. which worked quite well. Two bino's, two different ways to play.

 

[dduelin]

interesting set up Dave. Then you take pics of the white screen on the ground?

That's an IV bag hanger with the hooks cut off and a Ram ball inserted in the hollow tube.

Well, I can do that. I had a couple of set ups last eclipse - a pin hole projector and holding the binocs by hand.

 

[dduelin]

Got to remember that the image on a white screen is going to get hot as you get set up! I've seen a projection onto water in a bucket. which worked quite well. Two bino's, two different ways to play.

Last time there was a white (ish) sidewalk that worked as well as my piece of paper but who knows what the place will look like until we get to that place. If anything I can cover and uncover the aperture lens to aternately watch the shadow progress and then let things cool off. Best part is if my wife cannot make the trip with me in the car the whole set up collapses to 30" long and fits on the RT.

 

[STRider]

This was practice for Monday. Same setup I used in 2017.

Here's praying for clear skies around Dallas in a few days!!

Too off-topic?

 

[Xrayguy72]

The exit pupil diameter of the 10x42 will be 4.2mm the 7x50 will be 7.14mm
what is exit pupil diameter? Its the width of the beam of light leaving the eyepiece, usually measured in millimeters
So the 7x50 is going to project a bigger image on your white board compared to the 10x42.
Clearer? I have no idea in this application. LOL

 

[St-Gerard]

I hate it when I miss a botton, STrider that was supposed to be a like, blown away by them pics would be more accurate, but no botton for that.

 

[dwalby]

If those are the higher end Fujinons their optical quality is excellent, and they have a fixed focus so you don't have to play with a focusing wheel. I'm not sure if the lower grade Fujinons also have fixed focus or not, they might.

In theory the 7x50 should work better, but I'm not sure how much actual difference that would make for your intended application though, never tried it.

 

[STRider]

I hate it when I miss a botton, STrider that was supposed to be a like, blown away by them pics would be more accurate, but no botton for that.

<blush>

Yeah, I miss the usually available emojis in this forum too. Maybe prod @Mellow enough, and...

 

[dduelin]

If those are the higher end Fujinons their optical quality is excellent, and they have a fixed focus so you don't have to play with a focusing wheel. I'm not sure if the lower grade Fujinons also have fixed focus or not, they might.

In theory the 7x50 should work better, but I'm not sure how much actual difference that would make for your intended application though, never tried it.

These are fixed focus design and worked very well for me when I had sailboats. At the time I bought them they were the best I could afford but they aren't Fujinon's highest quality. They will be fine for this task.

 

[SMSW]

You have time, why not set it up and view the sun on your target before the eclipse? Compare the two, then decide.

Question. If the binocs are left set up for a while, will they heat up at all and suffer any damage? This is a good idea and I might try it.

 

[Andrew Shadow]

I have no idea about binoculars but there was a piece on the news last night about using a camera to view/take photos of the eclipse. They warned that the camera can be damaged if a sun filter is not used to protect it. Same applies to smart phone cameras.

 

[SMSW]

I have no idea about binoculars but there was a piece on the news last night about using a camera to view/take photos of the eclipse. They warned that the camera can be damaged if a sun filter is not used to protect it. Same applies to smart phone cameras.

Sure, focusing the sun on the sensor (or film) can burn it. Think the film is your retina if you look at the sun w/o protection.

 

[DannoXYZ]

You can get neutral-density sun filtres to place over objective lenses of binoculars to dim light even before it gets in. Then place phone‘s camera where eyeball usually goes at eyepiece. View image on front of camera. Snap photos as needed.

Amazon - DayStar filtres for binoculars
GoSky cell-phone holder
Amazon - phone to eyepiece holder





Most likely they’ll be clouds in way.

 

[williscreg]

Good to know, thanks for the tip. I've been thinking about getting myself a new pair of binoculars lately, and I've already started browsing the options on wweshop. Quality is definitely my priority when it comes to something like this, so I'm prepared to invest a couple of grand if it means getting the best pair possible. Can't wait to find the perfect set for my outdoor adventures

 

[spiderman302]

Projecting with the binos might be difficult since the focus point is only about a half inch from the eye piece.
You would have to put a business card close to the lens to see the sharp projected image else it will be out of focus.
If you have an old 35 mm telephoto lens (300mm and up) it would give you more distance to project and make a bigger image.
The longer the lens the harder it will be to keep tracking without a clock drive.
Might have to dig out the old speed graflex lens.
The pin hole projection method using a large cardboard box would work as well.
I will only get to see a 50% eclipse from my location at 11:12 am.




notice the shadow at their feet, sun is behind them....

 

[dduelin]

Projecting with the binos might be difficult since the focus point is only about a half inch from the eye piece.
You would have to put a business card close to the lens to see the sharp projected image else it will be out of focus.
If you have an old 35 mm telephoto lens (300mm and up) it would give you more distance to project and make a bigger image.
The longer the lens the harder it will be to keep tracking without a clock drive.
Might have to dig out the old speed graflex lens.
The pin hole projection method using a large cardboard box would work as well.
I will only get to see a 50% eclipse from my location at 11:12 am.



notice the shadow at their feet, sun is behind them....

The focal length might be .5 inch but at 8” the image is more than acceptable as this shows. It’s the size of a quarter. I have a 12” square piece of cardboard that fits tightly on top of the one side of the 7x50s that casts a shadow for the white viewing surface.

 

[spiderman302]

Yes it does work....

for tomorrow.

 

[dwalby]

hey Paul, you just gave me an idea since I'll be home for tomorrow's eclipse and I have a spotting scope and tripod that I could configure like your photo shows.

Just wanted to ask, do you need to put any type of neutral density filter in front of the scope, or just let the sun shine directly into it?