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Old 2017-07-19, 11:49   #45
only_human
 
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I imagine that people will aim their phones and cameras at the sun;

1) do you the devices are ok aimed at the sun?
2) would looking at the display of a device that is aimed at the sun be an ok experience?
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Old 2017-07-19, 12:32   #46
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Aim nothing with a lens at the sun without proper filtering.*

The display would be safe to look at. However I would only do so from the side, to avoid accidental exposure of the eyes to direct sunlight.

*Except during totality.
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Old 2017-07-19, 18:07   #47
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Quote:
Originally Posted by Uncwilly View Post
Aim nothing with a lens at the sun without proper filtering.*

The display would be safe to look at. However I would only do so from the side, to avoid accidental exposure of the eyes to direct sunlight.

*Except during totality.
Very importantly true- the lens in the camera, binocular, or telescope concentrates the light on the sensor, eyepiece, or your eye, and will likely permanently damage it. Be sure the filter is in front of the lens, and not behind it; in the "old days" small telescopes were often sold with a sun filter that was attached to the eyepiece, rather than covering the main telescope lens. The main lens concentrated light on the filter, which would heat up and eventually crack, which would then heat up and damage the eyepiece and/or someone's eye.

Norm
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Old 2017-07-20, 15:45   #48
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Quote:
Originally Posted by only_human View Post
I imagine that people will aim their phones and cameras at the sun;

1) do you the devices are ok aimed at the sun?
2) would looking at the display of a device that is aimed at the sun be an ok experience?
Looking at the display will be fine; looking through the eyepiece of a DSLR pointed at the Sun will *not* be fine; pointing a camera at the sun without a filter is quite a good way to set the sensor or the shutter on fire, which is very far from good for the camera.

During the transit of Venus in 2004 I set up a telescope for projection, but managed to set fire to the eyepiece when I removed the aperture mask, because the image of the Sun didn't entirely lie on the object lens of the eyepiece and so I was sticking some fraction of fifteen watts onto not very many square millimetres of black plastic.

Last fiddled with by fivemack on 2017-07-20 at 15:49
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Old 2017-07-20, 16:04   #49
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This is the part where I try to say something intelligent to distance myself from my own inquiry.

I imagine the selfie generation is nevertheless going to degrade a lot of CMOS sensors on an upcoming Monday.
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Old 2017-07-20, 17:27   #50
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I will be in and around Yellowstone for the week preceding the eclipse.

Is anyone else planning to watch the eclipse from Grand Teton (or Rexburg, or Jackson etc)?
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Old 2017-07-20, 22:19   #51
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Quote:
Originally Posted by Batalov View Post
Is anyone else planning to watch the eclipse from Grand Teton (or Rexburg, or Jackson etc)?
Current plans are to be with a relative in the Casper, Wyoming area.
Although, I still plan to pass withing striking distance of the MersenneForum world headquarters later during my foray.

Last fiddled with by Uncwilly on 2017-07-20 at 22:21
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Old 2017-07-21, 01:59   #52
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Quote:
Looking at the display will be fine; looking through the eyepiece of a DSLR pointed at the Sun will *not* be fine; pointing a camera at the sun without a filter is quite a good way to set the sensor or the shutter on fire, which is very far from good for the camera.
In an SLR of any sort the mirror could be damaged, as well., maybe. I have taken many photos with the sun in the frame, but only on film cameras with good UV filtration.
Note: Unless your SLR has a clear screen with grid lines, you won't be seeing direct rays from the sun. Otherwise, you likely see a ground glass projected image. Still not something to stare at, nor point any camera at for very long (other than specialized devices or appropriate filtration).
I took lots of BW photos including the sun in landscapes. These were typically shot with heavy colored filtration. With film, you don't worry about burning the sensor, because there's always another frame. Might do something to the exposure system, though.

Last fiddled with by kladner on 2017-07-21 at 02:00
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Old 2017-07-21, 13:17   #53
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What would happen if you looked through a pair of binoculars, from the wrong end?

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Old 2017-07-21, 13:32   #54
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Quote:
Originally Posted by Xyzzy View Post
What would happen if you looked through a pair of binoculars, from the wrong end?
Quote:
Originally Posted by Uncwilly View Post
Aim nothing with a lens at the sun without proper filtering.*
....
*Except during totality.
Even then. Using binoculars without solar filters on the end closer to the sun can damage them. The heat can build up inside and cause problems with the interface between components.
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Old 2017-07-21, 14:38   #55
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Quote:
Originally Posted by Xyzzy View Post
What would happen if you looked through a pair of binoculars, from the wrong end?

With the same binoculars, you should instead simply project on a piece of paper.
The projected image is quite usable for a small group of people.
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