Transit of space station across the sun - 2 questions

I just stumbled across a photo of the transit of the space station, and the
shuttle across the sun.


http://www.astrophoto.fr/iss_atlantis_transit.html


I have two questions, each demonstrating my ignorance...

1) I don't see any sunspots... why not?

2) I see a lot of limb-darkening. Why? If the surface of the sun is
isotropic, isothermal and the atmosphere is at least as hot as the surface,
why the limb darkening?

cross posting to sci.astro

Alexander Thesoso wrote:
I just stumbled across a photo of the transit of the space station, and the
shuttle across the sun.


http://www.astrophoto.fr/iss_atlantis_transit.html


I have two questions, each demonstrating my ignorance...

1) I don't see any sunspots... why not?

2) I see a lot of limb-darkening. Why? If the surface of the sun is
isotropic, isothermal and the atmosphere is at least as hot as the surface,
why the limb darkening?

Dear
"Alexander Thesoso" wrote in
message news:EOxQg.1276$xh.869@trnddc02...
I just stumbled across a photo of the transit of the
space station, and the shuttle across the sun.


http://www.astrophoto.fr/iss_atlantis_transit.html

Good photo. Thanks for the link!

I have two questions, each demonstrating my ignorance...

1) I don't see any sunspots... why not?

Upper right hand corner of the image... you have to scroll across
to it. Also, with the "local" detail to focus the ISS and
shuttle, smaller sunspots may be lost.

http://www.lmsal.com/YPOP/Projection...t_MDI_CON.html

2) I see a lot of limb-darkening. Why?
If the surface of the sun is isotropic,

It isn't, exactly.

isothermal

It isn't, exactly.

and the atmosphere is at least as hot as
the surface,

Again, it isn't exactly.

why the limb darkening?

http://en.wikipedia.org/wiki/Limb_darkening

David A. Smith

Thank you... my bad... I was impatient and didn't look carefully enough.
The sunspot sure-enough is there.

"N:dlzc D:aol T:com (dlzc)" N: dlzc1 D:cox wrote in
message news:CMFQg.190$v43.183@fed1read02...
Dear
"Alexander Thesoso" wrote in message
news:EOxQg.1276$xh.869@trnddc02...
I just stumbled across a photo of the transit of the
space station, and the shuttle across the sun.


http://www.astrophoto.fr/iss_atlantis_transit.html

Good photo. Thanks for the link!

I have two questions, each demonstrating my ignorance...

1) I don't see any sunspots... why not?

Upper right hand corner of the image... you have to scroll across to it.
Also, with the "local" detail to focus the ISS and shuttle, smaller
sunspots may be lost.

http://www.lmsal.com/YPOP/Projection...t_MDI_CON.html

2) I see a lot of limb-darkening. Why?
If the surface of the sun is isotropic,

It isn't, exactly.

isothermal

It isn't, exactly.

and the atmosphere is at least as hot as
the surface,

Again, it isn't exactly.

why the limb darkening?

http://en.wikipedia.org/wiki/Limb_darkening

David A. Smith

On Thu, 21 Sep 2006 17:04:52 -0700, "N:dlzc D:aol T:com \(dlzc\)" N:
dlzc1 D:cox wrote:

Dear
"Alexander Thesoso" wrote in
message news:EOxQg.1276$xh.869@trnddc02...
I just stumbled across a photo of the transit of the
space station, and the shuttle across the sun.


http://www.astrophoto.fr/iss_atlantis_transit.html

Good photo. Thanks for the link!

I have two questions, each demonstrating my ignorance...

1) I don't see any sunspots... why not?

Upper right hand corner of the image... you have to scroll across
to it. Also, with the "local" detail to focus the ISS and
shuttle, smaller sunspots may be lost.

It looks like there's another one to the left of ISS and shuttle at
the edge.

One can also see the "active regions" that surround them.

In any case, its an amazing picture!


http://www.lmsal.com/YPOP/Projection...t_MDI_CON.html

2) I see a lot of limb-darkening. Why?
If the surface of the sun is isotropic,

It isn't, exactly.

isothermal

It isn't, exactly.

and the atmosphere is at least as hot as
the surface,

Again, it isn't exactly.

why the limb darkening?

http://en.wikipedia.org/wiki/Limb_darkening

David A. Smith