B Can We See This Massive Coronal Hole on the Sun?

[DaveC426913]

https://www.chron.com/news/space/article/coronal-hole-sun-18534248.php

I'm reading about this massive coronal hole that apparently spans much of the sun's disc.

Is it visible like a sunspot might be?

Is it the kind of thing that could be viewed with a pinhole camera arrangement?

 

[berkeman]

@Stavros Kiri @davenn

 

[DaveC426913]

I never did get an answer to this, and I suspect the observation window is rapidly closing.

 

[davenn]

Is it visible like a sunspot might be?

Sorry been away for a few days .... No, coronal holes are not optically visible

and I suspect the observation window is rapidly closing.

dont worry, another is central disk now .....

 

[DaveC426913]

No, coronal holes are not optically visible

Well that's hardly Instgrammable is it?
You must know some astro eggheads. Can you get them on that lickety-split?

 

[davenn]

Well that's hardly Instgrammable is it?
You must know some astro eggheads. Can you get them on that lickety-split?

Coronal holes are only seen at X-ray wavelengths. The best one they are seen at is like that of the
image above, which is 193 Angstroms (19.3 nanometre) wavelength.
Quote ....
"which highlights a spectral line emitted by iron atoms that have lost 11 electrons (also known as
iron-12 or Fe XII) at temperatures of 1,000,000 K"
end quote

1,000,000K is the typical temperature of the Solar Corona. The high temp of the corona was, for
many years, a great mystery as it sits above the much cooler photosphere ( around 6000K), the
visible *""surface"" of the sun, where the sunspots reside.

* we know it isnt a solid surfaceDave