Is it possible to see sunspots with the unaided eye?

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Discussion Overview

The discussion revolves around the possibility of seeing sunspots with the unaided eye, prompted by a participant's observation of a dark spot on the sun during cloudy conditions. The conversation explores various perspectives on visibility, safety concerns, and historical context regarding sunspot observation.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant describes seeing a dark spot on the sun that resembled a sunspot, questioning if this is a rational explanation.
  • Another participant asserts that sunspots can be seen with the unaided eye, but only if they are significantly large.
  • Concerns are raised about the dangers of looking at the sun without proper eye protection, with warnings about potential retinal damage.
  • A participant shares a fun experiment to determine if sunspots can be seen with the naked eye, involving calculations of angular resolution.
  • Some participants mention having seen large sunspots with solar glasses, while others note that subsequent sunspots were too small to be visible without magnification.
  • There is a reference to historical instances of sunspots being viewed with the unaided eye, suggesting that it has been possible in the past.
  • Disagreement exists regarding the specific conditions and size required for sunspots to be visible without protection.

Areas of Agreement / Disagreement

Participants express differing views on whether sunspots can be seen with the unaided eye, with some asserting it is possible under certain conditions, while others emphasize the risks and limitations involved. The discussion remains unresolved regarding the specifics of visibility and safety.

Contextual Notes

Participants reference personal experiences and historical observations, but there is uncertainty about the exact conditions under which sunspots can be seen without protection. The discussion also highlights the variability in sunspot size and visibility over time.

BenAS
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This has been bugging me for a while, I'm not sure what I saw exactly. A few months ago there was some thin clouds blowing past the sun, obscuring it to the point you could easily look at the disk with the unaided eye. There was a dark spot, that looked like a sunspot as seen in filtered pictures of the sun. The clouds were blowing by fast and the spot didn't change position on the sun for 10-15 minutes I was watching it. Is a sunspot a rational explanation for it?
 
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Yes, but they have to be ginormous.
 
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Unlikely. More likely is that you already damaged your retina, which produces the dark point. I strongly recommend NOT to look into the sun with unprotected eyes, and sunglasses are NOT sufficient, clouds even less. This is a sure way to burn your retina or parts of it with no chances to ever get recovered. DO NOT DO THIS!
 
fresh_42 said:
Unlikely. More likely is that you already damaged your retina, which produces the dark point. I strongly recommend NOT to look into the sun with unprotected eyes, and sunglasses are NOT sufficient, clouds even less. This is a sure way to burn your retina or parts of it with no chances to ever get recovered. DO NOT DO THIS!
I would think the dark point would move around with my vision (like floaters, which I have). Not stay exactly the same place on the sun for 10-15 minutes

Edit: I was not staring at it the whole time, I kept looking back at it when it wasn't too bright. But wise advice nonetheless
 
Do you know the exact date it happened?
 
Bandersnatch said:
Do you know the exact date it happened?
No, unfortunately not.
 
BenAS said:
This has been bugging me for a while, I'm not sure what I saw exactly. A few months ago there was some thin clouds blowing past the sun, obscuring it to the point you could easily look at the disk with the unaided eye. There was a dark spot, that looked like a sunspot as seen in filtered pictures of the sun. The clouds were blowing by fast and the spot didn't change position on the sun for 10-15 minutes I was watching it. Is a sunspot a rational explanation for it?

Yes, sunspots have been viewed with unaided eyes for millennia:

https://www.windows2universe.org/sun/activity/sunspot_history.html
http://chandra.harvard.edu/edu/formal/icecore/The_Historical_Sunspot_Record.pdf
 
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According to Stavros you can:

Stavros Kiri said:
...

When I saw it it was still about the size of Jupiter (I caught it on the verge ...). So no need to have a falcon eye. It was expected (to be visible by "naked eye").

If I can still see it today (meaning tomorrow July 15) (with just the solar glasses) I'll probably change my profile name ... to "falcon" ...:biggrin:

A fun experiment I just devised, to see if you can see sunspots with your naked eye:

1. Pull up Stavros's image of the sunspots on your computer.

2017.08.24.OmCheeto.eyeball.resolution.png


2. Aim it towards a distant location.
3. Measure the diameter of the sun on your monitor.
4. Walk as far away from your monitor as possible.
5. Start walking towards your monitor, until you can just "sense" that the sunspots are present.
6. Measure the distance to your monitor.
7. Do a bunch of fancy maths, and determine the angular resolution of your eyes. [3]
8. Google the angular diameter of the sun as viewed from Earth. [1]
9. If the angular resolution of your eyes[2] is greater than the angular diameter of the sun, then you cannot see sunspots.

ps. I cannot see sunspots with my naked eyes. Though, I'm old, and accept the fact that all of my equipment is wearing out, and am not ashamed to admit it.

[1] 32 arc-minutes (sun as seen from earth)
[2] 100 arc-minutes (Om has to magnify the sun 3 times to see sunspots.)
[3] I would do this for you, but I did the maths long ago in the "Ceres" thread, where I plugged the equations into a spreadsheet, as I knew it would come in handy one day, as I can't remember my sines from cosines for squat. But, I'm sure it wasn't that hard.
 
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  • #10
The one I saw back on July 13 was huge. But still I was wearing solar eclipse glasses (no magnification due to other instruments).
Stavros Kiri said:
It's even visible with naked eye, solar glasses of course ! Just got the chance to see it ...
With totally naked and unaided eye it's a bad idea! @fresh_42 's warning is an important one!

Subsequent sun spots have been much smaller and I haven't been able to see them with just the solar glasses - I admit it too.
The latest ones (around eclipse time) are just about visible with binoculars (I used 12×30 even today) [&filter], if you focus properly and you know where to look ...
 
  • #11
BenAS said:
Is a sunspot a rational explanation for it?

yes a good explanation

russ_watters said:
Yes, but they have to be ginormous.
I agree with Russ ... yes but they have to be pretty large ones
BenAS said:
No, unfortunately not.

That is unfortunate as I have a full set of data that goes back many years

you can't even give a month and part of that month ... I don't need the specific day
BenAS said:
I would think the dark point would move around with my vision (like floaters, which I have). Not stay exactly the same place on the sun for 10-15 minutes

that is true ... sunspot is most likely reason

Dave
 
  • #12
Thanks everyone for the comprehensive answers
 
  • #13
BenAS said:
Thanks everyone for the comprehensive answers
you didn't answer my Q
 
  • #14
davenn said:
you didn't answer my Q
Sorry it was so long ago, thinking more about it I think it was 2.5 years ago (from my memory of where I was working) best guess is February-March 2015 or earlier. That's the best I can come up with
 
  • #15
BenAS said:
Sorry it was so long ago, thinking more about it I think it was 2.5 years ago (from my memory of where I was working) best guess is February-March 2015 or earlier. That's the best I can come up with
ohhh ok ... in your OP you said a few months ago, hence why I questioned you :wink:
 
  • #16
davenn said:
ohhh ok ... in your OP you said a few months ago, hence why I questioned you :wink:
It was something I didn't think much about at the time, the eclipse (which btw was amazing) made me think about it again.
 
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