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Fraser
2005-Oct-06, 07:36 PM
SUMMARY: This amazing image is of a sunspot three times the size of the Earth. The photograph was taken using the National Science Foundation's Dunn Solar Telescope at Sunspot, NM, which was recently upgraded with an adaptive optics system. The Dunn telescope has a flexible mirror which can be deformed 130 times a second to compensate for atmospheric distortion. This image was made with 80 individual photographs combined together.

View full article (http://www.universetoday.com/am/publish/sharpest_image_sunspot.html)
What do you think about this story? post your comments below.

galacsi
2005-Oct-06, 07:50 PM
Hi

In the full story there is this sentence : "Magnetism in solar activity is the "dark energy problem" being tackled in solar physics today."
I don't undestand . What is this dark energy problem ? Somebody can explain it to me ?

Thanks

iantresman
2005-Oct-06, 10:04 PM
In the full story there is this sentence : "Magnetism in solar activity is the "dark energy problem" being tackled in solar physics today."
I don't undestand . What is this dark energy problem ? Somebody can explain it to me ?

I heard that when astronomers don't understand something, they attribute /blame it on magnet fields.

The only energy missing from a better understanding of the sun is electric energy. But I'm biased.

Regards,
Ian Tresman

tbm
2005-Oct-06, 10:35 PM
What a fantastic image. Now I know where David Icke and his lizard people are hiding!

Regards, tbm

Random63
2005-Oct-07, 04:38 AM
I look at that picture and it reminds me of looking at something biological under a microcscope. Very weird!

iantresman
2005-Oct-07, 12:53 PM
I look at that picture and it reminds me of looking at something biological under a microcscope. Very weird!
Recall that a Sun is in the plasma state, a word that was applied to ionized gases by Irving Langmuir because they reminded him of the behaviour of blood plasmas [Ref (http://www.plasmacoalition.org/what.htm) ]. And subsequently Hannes Alfvén noted that plasmas can tend to form cell-like regions. Personally, I do not think it is completely coincidental.

Regards,
Ian Tresman

Jerry
2005-Oct-10, 05:23 PM
I heard that when astronomers don't understand something, they attribute /blame it on magnet fields.

The only energy missing from a better understanding of the sun is electric energy. But I'm biased.

Regards,
Ian Tresman
I don't see the conflict. If there is moving plasma, plasma is by definition in a charged electromagnetic state. Which, arranged in a pattern like this, would certainly generate a whooping magnetic field, which also explains why the pattern exists...

...which of course, does not explain why such a massive, concentrated emf exists in the first place.

There is much to learn.

galacsi
2005-Oct-10, 07:38 PM
I don't see the conflict. If there is moving plasma, plasma is by definition in a charged electromagnetic state. Which, arranged in a pattern like this, would certainly generate a whooping magnetic field, which also explains why the pattern exists...

...which of course, does not explain why such a massive, concentrated emf exists in the first place.

There is much to learn.

The big question is can a gas or a plasma product a magnetic field without being crossed by electric currents ?

I undestand a plasma can be magnetised by an external magnetic field , but it is not my question .

Who come first, the magnetic hen or the electric egg ?

Michael Mozina
2005-Oct-11, 05:43 PM
SUMMARY: This amazing image is of a sunspot three times the size of the Earth. The photograph was taken using the National Science Foundation's Dunn Solar Telescope at Sunspot, NM, which was recently upgraded with an adaptive optics system. The Dunn telescope has a flexible mirror which can be deformed 130 times a second to compensate for atmospheric distortion. This image was made with 80 individual photographs combined together.

View full article (http://www.universetoday.com/am/publish/sharpest_image_sunspot.html)
What do you think about this story? post your comments below.

The results seem extremely impressive. I wonder how such technology might work on a different body in the solar system. It seems to me that this kind of technology could significantly improve many areas of astronomy, not just solar astronomy, but there may be something about the technique that is specific to the sun in some way. I'm not quite sure what kind of "magic" they do to combine the indivual images together. The results however are quite impressive.

George
2005-Oct-11, 07:47 PM
The results seem extremely impressive. I wonder how such technology might work on a different body in the solar system. It seems to me that this kind of technology could significantly improve many areas of astronomy, not just solar astronomy, but there may be something about the technique that is specific to the sun in some way. I'm not quite sure what kind of "magic" they do to combine the indivual images together. The results however are quite impressive.
Adaptive Optics (AO) is fairly new technology. IIRC, it came from an astronomer from the Air Force. It has been incorporated in large non-solar scopes with amazing results, too.

An object appears to move due to the turbulence in our atmosphere. By slightly moving the mirror to correct this, much higher resolution is possible. I am not that familiar with it in detail. I believe they use a laser to monitor the wiggle in the air, which would seem easier to track at night. The mirror movement rate is up to 130 times/sec, according to the article.

Also, by taking very fast images (short exposure time), there is much less blur from atmospheric turbulence. Numerous images are added to each other to make it brighter, but each is properly selected and aligned to yield the best results (i.e. stacking). This is my crude understanding of it as I've yet to do it.


I notice the space between the granules is lighter in shade than the granules themselves. Isn't this region downward-directed gas, which should be cooler, therefore, darker?

[Added: I won't comment on the color selection. :razz: ]

Baloo
2005-Oct-11, 08:58 PM
An object appears to move due to the turbulence in our atmosphere. By slightly moving the mirror to correct this, much higher resolution is possible. I am not that familiar with it in detail.

Maybe it should be pointed out that the adaptative optics is an improvement only for Earth based telescopes; that doesn't necessarly make them better than space based telescopes, but Earth telescopes have the big advantage of not being restricted in size and weight.

George
2005-Oct-11, 11:42 PM
Maybe it should be pointed out that the adaptative optics is an improvement only for Earth based telescopes; that doesn't necessarly make them better than space based telescopes, but Earth telescopes have the big advantage of not being restricted in size and weight.
Yes. AO is superfluous in space. Size and weight are problems here, too, but the bottom line is much easier on the pocket book down here.

We really need both, of course. Losing the HST would, and likely will be, a tough blow.

Michael Mozina
2005-Oct-12, 03:35 AM
Maybe it should be pointed out that the adaptative optics is an improvement only for Earth based telescopes; that doesn't necessarly make them better than space based telescopes, but Earth telescopes have the big advantage of not being restricted in size and weight.

I can sure see the benefit of being able to swap out filters and cameras on a ground based telescope with this sort of technology while studing our own sun. I can also still see a need however for an instrument like Hubble and Spitzer where maximum precision is required. It does seem like a quantum leap forward for ground based telescopes.

Kaptain K
2005-Oct-12, 03:53 AM
The results seem extremely impressive. I wonder how such technology might work on a different body in the solar system. It seems to me that this kind of technology could significantly improve many areas of astronomy...

It can and does. Most of the big scopes have been fitted with or are in the process of being fitted with AO.

...there may be something about the technique that is specific to the sun in some way. I'm not quite sure what kind of "magic" they do to combine the indivual images together. The results however are quite impressive.
The only "new" techniques involved are the specific ones needed to apply AO to solar imaging.

George
2005-Oct-12, 12:46 PM
The only "new" techniques involved are the specific ones needed to apply AO to solar imaging.
Apparently, solar AO does not have the advantage that night time AO has by using point-source stars as reference. Sunspots and granules are used for solar AO reference points which requires much more effort, per reference (http://nsosp.nso.edu/ao/).

The OP linked article states there are two AO systems incorporated at Dunn. I wonder what this means?

kristinc
2005-Oct-12, 01:32 PM
The Swedish Solar Telescope in La Palma never seems to be mentioned much in popular science news, although it is one of the most important ground-based instruments for studying the Sun (as I understand it). In 2002 it rendered images of sunspots considered still to be THE best pictures taken of the Sun ever. As you can see, the crispness is strikingly near the one taken only recently by the Dunn telescope:

http://www.solarphysics.kva.se/NatureNov2002/images/AR10030_4877_color.jpeg
http://www.solarphysics.kva.se/NatureNov2002/images/np1_fig1_columnwidth_color.jpeg

(Could this bias come from the fact that the SST isn't an American telescope?)

:) Kristin

Michael Mozina
2005-Oct-12, 03:24 PM
The Swedish Solar Telescope in La Palma never seems to be mentioned much in popular science news, although it is one of the most important ground-based instruments for studying the Sun (as I understand it). In 2002 it rendered images of sunspots considered still to be THE best pictures taken of the Sun ever. As you can see, the crispness is strikingly near the one taken only recently by the Dunn telescope:

http://www.solarphysics.kva.se/NatureNov2002/images/AR10030_4877_color.jpeg
http://www.solarphysics.kva.se/NatureNov2002/images/np1_fig1_columnwidth_color.jpeg

(Could this bias come from the fact that the SST isn't an American telescope?)

:) Kristin

Gee, ya think? :)

Michael Mozina
2005-Oct-12, 03:25 PM
By the way....Dr. Kristian Birkeland was is one of my all time heroes as it relates to solar physics.

iantresman
2005-Oct-13, 03:49 PM
The big question is can a gas or a plasma product a magnetic field without being crossed by electric currents ?

I undestand a plasma can be magnetised by an external magnetic field , but it is not my question .

Who come first, the magnetic hen or the electric egg ?

Plasmas can (a) Self-generate magnetic fields (b) Self-generate electric fields (and hence electric currents). See: Self-generated magnetic fields in plasmas (http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1977JPlPh..18..227P&db_key=PHY&link_type=ABSTRACT&high=42ca922c9c07565) (1977), Pert, G. J.
Self-generated magnetic fields in laser-produced plasmas (http://adsabs.harvard.edu/cgi-bin/nph-abs_connect?db_key=AST&db_key=PHY&sim_query=YES&aut_xct=NO&aut_logic=OR&obj_logic=OR&author=&object=&start_mon=&start_year=&end_mon=&end_year=&ttl_logic=AND&title=self-generated+magnetic+plasma%0D%0A&txt_logic=AND&text=&nr_to_return=100&start_nr=1&jou_pick=ALL&ref_stems=&data_and=ALL&group_and=ALL&start_entry_day=&start_entry_mon=&start_entry_year=&end_entry_day=&end_entry_mon=&end_entry_year=&min_score=&sort=SCORE&data_type=SHORT&aut_syn=YES&ttl_syn=YES&txt_syn=YES&aut_wt=1.0&obj_wt=1.0&ttl_wt=0.3&txt_wt=3.0&aut_wgt=YES&obj_wgt=YES&ttl_wgt=YES&txt_wgt=YES&ttl_sco=YES&txt_sco=YES&version=1) (1972-2001)
Distribution of self-generated current in laser-produced plasmas (http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1976PhRvL..36..591D&db_key=PHY&link_type=ABSTRACT&high=42ca922c9c09151) (1976), Drouet, M. G.; Bolton, R.

You'd think that astronomers would know little more about plasmas since it makes up over 99.999% of the Universe by volume. The big question then, is how do these magnetic and electric fields affect this plasma?

Regards,
Ian Tresman

LurchGS
2005-Oct-20, 09:07 PM
Yes. AO is superfluous in space. Size and weight are problems here, too, but the bottom line is much easier on the pocket book down here.

We really need both, of course. Losing the HST would, and likely will be, a tough blow.

Yes, AO is superflous in space... in fact, since AO is now capable of achieving apparent diffraction limits that equal that of HST, HST is obsolete. (.1 arc-second is .1 arc-second, whether it be 600 miles up or in my back yard)

In fact, I wonder if AO might not make the need for a Large Scale Optical Array Telescope in space unneccessary... unless we set the edges of the array farther apart than the diameter of the earth.. THAT should provide for some serious images.

------------

Man's reach MUST exceed his grasp, or what's a weapon for?

George
2005-Oct-20, 09:44 PM
Yes, AO is superflous in space... in fact, since AO is now capable of achieving apparent diffraction limits that equal that of HST, HST is obsolete. (.1 arc-second is .1 arc-second, whether it be 600 miles up or in my back yard)
Achieving this resolution on Earth is quite amazing. However, it makes good sense to have both. I do not think the .1" works across the spectrum quite like the HST. Also, there are obvious ground observing issues including clouds and daytime. [Of course, I will encourage solar observation. ;)] Speaking of the sun...helioseismology, another example, would be a real headache without the stationary position (L1) of Soho.


In fact, I wonder if AO might not make the need for a Large Scale Optical Array Telescope in space unneccessary... unless we set the edges of the array farther apart than the diameter of the earth.. THAT should provide for some serious images. Hmmmm....an L4 to L5 link would be nice, and we wouldn't even need to drill a hole through the Earth to do it. :)