Moderated Iron sun with Aether batteries...

[brantc]

So back to what TRACE images?

I hope that you do not mean the artifact of limb ghosting introduced by the detector in some TRACE images that has already been comprehensively addressed by Tim Thompson:

• Solar "Ghost Limb" Is An Optical Artifact
• The Solar "Ghost Limb" Is An Optical Artifact II
• The Solar "Ghost Limb" Is An Optical Artifact III

Actual observations of the Sun (ignoring optical artifacts!) have always found that the photosphere is below the lower transition layer/upper chromosphere. Once again covered very well by Tim Thompson

• The Solar EUV Radius
• The Solar EUV Radius II
• The Solar EUV Radius III
• The Solar EUV Radius V

I addressed those comments.

The filter response is a result of the mirror coating which enhances 1500A.
This exceeds the filters attenuation capabilities.
This would not produce a ghost image. A filter doesnt work like that.


Then there is the problem that would produce a ghost image, a wedge shaped filter by 2 degrees. So they mathematically corrected for that.
You trust math, dont you?

The authors said "The correction mechanism described in this paper is able to remove part of the ghosted limb, but it is evident that corrected limb images are still not right. What is left is evidently some form of limb brightening that is not corrected by this method."
http://wwwsolar.nrl.navy.mil/rockets/vault/pubs/trace.pdf
Images are on page 11.

Which is at odds with what others here have claimed.
I agree with the authors conclusion. The "artifact" is on the sun and not in the telescope.

They think their correction is good enough to release software for the rest of the scientific community.
"An IDL routine, lya_subtract.pro, has been added to the Solarsoft tree and will be available with the SSW/TRACE software distribution."

I think I believe the data.

So do you think they know what they are talking about? If not show me why.

 

[Reality Check]

I addressed those comments.

The filter response is a result of the mirror coating which enhances 1500A.
This exceeds the filters attenuation capabilities.
This would not produce a ghost image. A filter doesnt work like that.


Then there is the problem that would produce a ghost image, a wedge shaped filter by 2 degrees. So they mathematically corrected for that.
You trust math, dont you?

The authors said "The correction mechanism described in this paper is able to remove part of the ghosted limb, but it is evident that corrected limb images are still not right. What is left is evidently some form of limb brightening that is not corrected by this method."
http://wwwsolar.nrl.navy.mil/rockets/vault/pubs/trace.pdf
Images are on page 11.

Which is at odds with what others here have claimed.
I agree with the authors conclusion. The "artifact" is on the sun and not in the telescope.

They think their correction is good enough to release software for the rest of the scientific community.
"An IDL routine, lya_subtract.pro, has been added to the Solarsoft tree and will be available with the SSW/TRACE software distribution."

I think I believe the data.

So do you think they know what they are talking about? If not show me why.

Yes they know what they are talking about.

They are talking about an artifact introduced in the detector by the properties of the detector as explained to you by Tim Thompson.

They are talking about techniques to correct for that artifact introduced in the detector by the properties of the detector.

I agree with the authors conclusion. There is limb brightening introduced by the detector that is not corrected for by their method.

 

[Reality Check]

The authors said "The correction mechanism described in this paper is able to remove part of the ghosted limb, but it is evident that corrected limb images are still not right. What is left is evidently some form of limb brightening that is not corrected by this method."
http://wwwsolar.nrl.navy.mil/rockets/vault/pubs/trace.pdf
Images are on page 11.

I forgot about the actual caption for figure 5 which you seem to be ignoring.
http://wwwsolar.nrl.navy.mil/rockets/vault/pubs/trace.pdf

Figure 5. A manifestation of the wedge in the UV entrance filter. In (a) a ghost of the UV continuum (present in the 1600 image) is evident as a bright band about 2 arc sec above the limb. Correlating the
1216 and 1600 Å images to one another places the 1600 Å limb squarely on this ghost limb. Image (b) is the result of applying the correction algorithm to the TRACE image used in (a). The ghost is still evident after correction.

So the authors are talking about the effect of the wedge in the UV entracne filter (not anything actually on the Sun). They call this effect

• a manifestation and
• a ghost

They call an image with this effect a ghosted image, i.e an image with a ghost on it.

Ghosts are not real.

P.S. You should also read the abstract where the intentions of the authors is clearly stated to be to remove the "contamination" (their word!) of the ghosted limb from the image.

 

[Tim Thompson]

The Solar "Ghost Limb" Is An Optical Artifact IV

The authors said "The correction mechanism described in this paper is able to remove part of the ghosted limb, but it is evident that corrected limb images are still not right. What is left is evidently some form of limb brightening that is not corrected by this method." ... Which is at odds with what others here have claimed.

No it is not. The authors compensate for the angular offset of the filter (which is 2 arcseconds, not 2 degrees, as you said, which I assume to be a typo on your part). However, they have to model the brightness of 1600 Å emission to subtract. if that model does not precisely duplicate the brightness of 1600 Å emission found on the real solar limb, then the subtraction will not accurately compensate. That's what the limb brightening comment refers to.

The model used is expressed in equation (3):
I_L-alpha = A x I₁₂₁₆ + B x I₁₆₀₀

And the values for A & B are given in equation (4):
A = 0.97, B = -0.105

So the point of the limb brightening comment is that the value of B is inadequate to compensate for limb brightening.

They think their correction is good enough to release software for the rest of the scientific community.

They do, but read the paper more carefully. Look at the middle paragraph of the discussion section:

It is important to note that the method presented here is by no means exact. Researchers seeking high precision photometry measurements of L-alpha from TRACE should pay heed to the level of accuracy that is reasonable. This method assumes a reasonably predictable UV continuum background. That aside, we believe these measurements apply anywhere on the solar disk, in quiet-Sun regions or bright active regions. The method does not work well above the solar limb, and the level of complexity there discourages a very high level of accuracy.
Handy, et al., 1999; 2nd paragraph of discussion section (4).
​

The reference in the paragraph above, concerning not working well above the solar limb, is precisely on point. Above the solar limb is exactly where the 1600 Å emission they want to subtract is located. The primary value of the IDL routine they distribute is that it will correct exactly for the angular offset from the wedge effect. However, the drawback is that it will not correct exactly for the UV continuum if it falls outside the "reasonably predictable" regime they rely on. Hence the warning to pay heed to accuracy requirements.

I agree with the authors conclusion. The "artifact" is on the sun and not in the telescope.

That is not the conclusion of the authors. In fact the authors are explicit in saying that the artifact is an artifact, in the telescope, and not on the sun (see my previous posts The Solar "Ghost Limb" Is An Optical Artifact III & The Solar "Ghost Limb" Is An Optical Artifact III). The "artifact" is an artifact inside the telescope and nothing more real than that.

 

[The Man]

But of course: those phenomena which are observed and possible to reproduce in the lab should be. In many cases, this will allow finer detail and more subtle effects to be noticed and quantified.

Some phenomena occur in nature only on scales that are impossible to replicate in any laboratory setting; Evolution (abiogenisis, natural selection and species differentiation) is limited by the time scale and sample size scale limitations, Geodynamics (plate tectonics and vulcanism) are also limited by time scale and mass scale.

Some things cannot be easily isolated and controlled; they can only be observed and modeled.



Any craziness you exhibit is only due to the fact that you therefore actually blind yourself to vast areas of perfectly valid science that doesn't have any practical scalability to a lab environment.

Lots of people work in labs everyday without having the least modicum of scientific qualification, knowledge, or rigor of reasoning powers to even be trusted to accurately report if the sun is shining outside; I give you 0 points for even making that assertion.



When that is valid, that is how it should be done. It is stunningly wrong, however, to disallow other means when scaling from lab scale is not applicable.

BTW, what do you think "extrapolate[ing] from known hard data" IS besides mathematical modeling and "thought experiment"?



I think you are suffering from the science-philosophy equivalent of total color blindness and tone deafness; you are not able to perceive what you are missing and believe everyone else is just making things up to mess with your head.

Cheers,

Dave

Nominated

 

[brantc]

Ok. What is limb brightening and is that a phenomena of the sun of a telescope??

 

[Reality Check]

Ok. What is limb brightening and is that a phenomena of the sun of a telescope??

Limb brightening is the brightening of the Sun's limb in images caused by the method used to attempt to remove the contamination caused by the properties of the detector. It is not a phenomena of the sun. It is not a phenomena of the telescope. It is a phenomena of the method.

 

[Tim Thompson]

The Solar "Ghost Limb" Is An Optical Artifact V

Ok. What is limb brightening and is that a phenomena of the sun of a telescope??

Limb brightening is the brightening of the Sun's limb in images caused by the method used to attempt to remove the contamination caused by the properties of the detector. It is not a phenomena of the sun. It is not a phenomena of the telescope. It is a phenomena of the method.

On this occasion RC is mistaken. Limb brightening is a phenomenon of the sun, not of the telescope. See the Wikipedia page on limb darkening and see the discussion in the book Solar Astrophysics by Peter Foukal (Wiley-VCH 2004; 2nd, revised edition), on page 135, section 5.1.1 "Limb Darkening".

Under most circumstances we encounter limb darkening because as our line of sight migrates from the center portions of the solar disk towards the limb, we are seeing into cooler & cooler layers of the photosphere. The cooler layers are intrinsically dimmer, so the light from the sun tends to dim as we approach the limb of the solar disk. Hence the title of "limb darkening".

However, there is a temperature minimum in the photosphere. Once our line of sight passes that temperature minimum we are now seeing hotter & hotter layers, not cooler & cooler layers. The hotter layers emit at shorter wavelengths due to their higher temperature. So at shorter wavelengths than visible light, in violet & ultraviolet light, the limb of the sun brightens instead of getting dimmer. The phenomenon of limb darkening gives way to the new phenomenon of limb brightening.

In the case of our optical artifact, we should not expect to see limb brightening at 1216 Å because it is the hydrogen-alpha emission line and should be equally bright everywhere (it is non-thermal emission). However, at 1600 Å we should see limb brightening because it is continuum emission, not line emission, and will be sensitive to the increasing photospheric temperature in the successively higher layers.

As noted in my previous post, The Solar "Ghost Limb" is an optical artifact IV, there is a simple linear model for the 1600 Å continuum. the conclusion the authors of the paper (Handy, et al., 1999) come to is that their model does not adequately describe the true 1600 Å brightness of the sun, probably because there is limb brightening on the sun that they are not properly compensating for.

It is also noteworthy that the transition from limb darkening to limb brightening as we move from visible to ultraviolet wavelengths also deals with earlier claims, by Mozina in particular, that the transition layer was below the visible photosphere as opposed to above it. Limb brightening proves the opposite, that the transition layer is where we think it is, namely above the visible photosphere.

Limb brightening is not as heavily studied as is limb darkening, but there are references to observations of limb brightening in the literature, e.g., Gimenez de Castro, et al., 2008, Crane, et al., 2001.

 

[ben m]

To simplify what Tim said:

The image brantc is looking at is not raw data; it's not a real, simple picture of the Sun in h-alpha light. The picture is, rather, the difference between two images. They take the 1216A image (which contains both H-alpha and background) and subtract a synthetic image which contains their best guess at the background. The subtraction would be the desired h-alpha image if the synthetic background image were perfect. The synthetic image is not perfect---it's derived from the 1600A image via an imperfect model. Therefore the subtracted image isn't quite an H-alpha image, and the errors are most pronounced (the model is least reliable) at the limb.

 

[brantc]

No it is not. The authors compensate for the angular offset of the filter (which is 2 arcseconds, not 2 degrees, as you said, which I assume to be a typo on your part). However, they have to model the brightness of 1600 Å emission to subtract. if that model does not precisely duplicate the brightness of 1600 Å emission found on the real solar limb, then the subtraction will not accurately compensate. That's what the limb brightening comment refers to.

The model used is expressed in equation (3):
I_L-alpha = A x I₁₂₁₆ + B x I₁₆₀₀

And the values for A & B are given in equation (4):
A = 0.97, B = -0.105

So the point of the limb brightening comment is that the value of B is inadequate to compensate for limb brightening.


They do, but read the paper more carefully. Look at the middle paragraph of the discussion section:

It is important to note that the method presented here is by no means exact. Researchers seeking high precision photometry measurements of L-alpha from TRACE should pay heed to the level of accuracy that is reasonable. This method assumes a reasonably predictable UV continuum background. That aside, we believe these measurements apply anywhere on the solar disk, in quiet-Sun regions or bright active regions. The method does not work well above the solar limb, and the level of complexity there discourages a very high level of accuracy.
Handy, et al., 1999; 2nd paragraph of discussion section (4).
​

The reference in the paragraph above, concerning not working well above the solar limb, is precisely on point. Above the solar limb is exactly where the 1600 Å emission they want to subtract is located. The primary value of the IDL routine they distribute is that it will correct exactly for the angular offset from the wedge effect. However, the drawback is that it will not correct exactly for the UV continuum if it falls outside the "reasonably predictable" regime they rely on. Hence the warning to pay heed to accuracy requirements.


That is not the conclusion of the authors. In fact the authors are explicit in saying that the artifact is an artifact, in the telescope, and not on the sun (see my previous posts The Solar "Ghost Limb" Is An Optical Artifact III & The Solar "Ghost Limb" Is An Optical Artifact III). The "artifact" is an artifact inside the telescope and nothing more real than that.

So your saying that they can compensate for the angular error but because of brightness variations in the UV continuum they cant 100% compensate for the convolution error from the enhanced 1500 response of mirror coatings.

Ok, so that couldnt come up empirical factor that covers the range of brightness variations from the continuum and transition region.

So lets look at the next paper.

Look at the time series on page 4. Figure 2b in 1216 shows a brightening on Handys Ghost Limb. Is it real or not? They must have thought it was interesting to include it in the series.....
http://arxiv.org/PS_cache/arxiv/pdf/0902/0902.1805v2.pdf

The circles are RHESSI isocontours. "The filament apex is marked by the plus sign whose horizontal and vertical extents represent the positional uncertainty in each direction." The preceding and following frames are 195A. Notice from image to image everything lines up. The brightening on the ghost limb is below the transition region at 195. The loop is at the correct position with the brightening below the loop. You said yourself they are able to correct angular dislocation.

You can tell the difference between the transition region and the UV continuum. The brightening is taking place in the chromosphere(ghost limb) UV continuum.

Here is my composite of image from the 2 papers.
http://www.box.net/shared/833e2lbx10

 

[Reality Check]

Look at the time series on page 4. Figure 2b in 1216 shows a brightening on Handys Ghost Limb. Is it real or not? They must have thought it was interesting to include it in the series.....
http://arxiv.org/PS_cache/arxiv/pdf/0902/0902.1805v2.pdf

All you have to do is read the caption and then the citation.

Selected TRACE 1216 °A (panel b) and 195 °A (other panels) maps labeled by their exposure intervals during Phase I.
Superimposed are RHESSI PIXON image contours at 3–6 keV integrated in 40 s intervals, whose central times coincide with those of the
corresponding TRACE maps. Contour levels at percentages of the image maximum are given in parentheses. The filament apex is marked
by the plus sign whose horizontal and vertical extents represent the positional uncertainty in each direction. The dashed line, as defined
in Fig. 3c, indicates the fiducial direction for tracking source motions (see §2.1). Panel b shows the prominence as loop-shaped emission
at 1216 °A, where the bright spot below the northern leg is, most likely, an UV continuum brightening on the ghost limb that appears
2′′ above the true limb (Handy et al. 1999, their Fig. 5). The inserts in (g) and (h) offer a zoomed view of the helical structure of the
prominence. (GIF movies of this figure can be found at http://sun.stanford.edu/weiliu/movies/filamt-20030424)

The reason that they include this one mention of a ghost limb in their paper is that they saw the bright spot in the 1216 A TRACE image and mention the detector artifact as a likely cause of it, citing "Handy et al. 1999, their Fig. 5" which has the caption

Figure 5. A manifestation of the wedge in the UV entrance filter. In (a) a ghost of the UV continuum (present in the 1600 image) is evident as a bright band about 2 arc sec above the limb. Correlating the 1216 and 1600 Å images to one another places the 1600 Å limb squarely on this ghost limb. Image (b) is the result of applying the correction algorithm to the TRACE image used in (a). The ghost is still evident after correction.

In other words these authors think that the bright spot is a "manifestation of the wedge in the UV entrance filter" as stated in Handy et al. 1999.

Thus the answer is obvious: this is a real effect of the properties of the detector as in Handy et al. 1999.

 

[Reality Check]

Here is my composite of image from the 2 papers.
http://www.box.net/shared/833e2lbx10

A tiny note: the first image is from 1999, the second series of images are from April 24 2003. So there seems little point to me in superimposing them. But thanks for the effort to make the pretty pictures anyway.

 

[brantc]

So I tried to find out what was happening on that "limb". It turns out that the events that happen on that "limb" are what they call "white light flares"!

Here are some observations from 2003.

TRACE AND YOHKOH OBSERVATIONS OF A WHITE-LIGHT FLARE
http://sprg.ssl.berkeley.edu/adminstuff/webpubs/2003_aj_483.pdf

I thought that they were happening in the chromosphere. Maybe not according to HINODE. Maybe lower.
So then I found HINODE observation of the locations of the white light flares.

Hinode Discovers the Origin of White Light Flare
http://www.nasa.gov/centers/marshall/news/news/releases/2010/10-052.html

In this image here it shows how the white light flare kernel is correlated with the center of a sun spot. Yep.

http://www.nasa.gov/centers/marshall/images/content/455876main_fig2.gif
Fig.2: White light emission, left, taken by Hinode/SOT, and the difference image of white light emission and RHESSI hard X-ray contours at 22:09 UT. The background image is the differential white light image (the average of the images taken at 22:07 UT and 22:17 UT is subtracted). Blue contours show 40-100 keV emission. Image credit: NASA/JAXA

Ok. So heres the interesting thing. If HINODE finds the the white light kenrnels are happens a little lower in the solar atmosphere(1000km-about a wedge) then that puts them right at the solar surface.

Above Photosphere
In this media image from HINODE of the solar chromosphere shows the loops sticking up through the photosphere.

"Taken by Hinode's Solar Optical Telescope on Nov. 11, 2006, this image reveals the fine scale structure in the chromosphere that extends outward above the top of the convection cells, or granulation, of the photosphere. The structure results from the interaction of hot ionized gas with the magnetic field."
http://www.nasa.gov/mission_pages/hinode/solar_019.html

Below Photosphere
Again this is the image from TRACE is the loops on the solar surface below the photosphere. Notice the footprints of the loops. Notice the longitudinal features under the loops!!
http://trace.lmsal.com/POD/images/arcade_9_nov_2000.gif
http://trace.lmsal.com/POD/TRACEpodarchive6.html
More interesting images.
http://trace.lmsal.com/POD/images/T171_000404_183228.gif
http://trace.lmsal.com/POD/images/T171_000317_114103.gif

The TRACE mission has ended.

 

[Tubbythin]

Why not???

Why on Earth would it be? The only reason I can think this would be the case is if the Universe was designed specifically for humans to understand it. I have seen no evidence for this whatsoever.

Do you think that our physics is complete??

No. I have no idea why you even asked that question?

 

[Tim Thompson]

The Solar "Ghost Limb" Is An Optical Artifact VI

Look at the time series on page 4. Figure 2b in 1216 shows a brightening on Handys Ghost Limb. Is it real or not? They must have thought it was interesting to include it in the series.....
http://arxiv.org/PS_cache/arxiv/pdf/0902/0902.1805v2.pdf

The brightening is probably not real on the sun, but real only as an optical artifact, (a "ghost"). Like RC says, just read the figure caption: "Panel b shows the prominence as loop-shaped emission at 1216 Å, where the bright spot below the northern leg is, most likely, an UV continuum brightening on the ghost limb that appears ~2" above the true limb (Handy et al. 1999, their Fig. 5)."

The "ghost limb" is called a GHOST because it is not real on the sun, but rather an artifact of the optics in the telescope. So in the sense of being physically real on the sun, no it is not. The authors did not put that image in the sequence just because they "thought it was interesting to include", but because all of the other images are RHESSI X-ray images, and this one is the only TRACE UV image they have. The X-ray & UV correlation is potentially informative, and indeed the flare does show up in the TRACE image. But the bright blob on the limb does not show up in any of the RHESSI images. How does one explain that if the bright blob is physically real on the sun? As the authors say, the most likely explanation is that the bright blob is not physically real on the sun, but rather a ghost of the TRACE optics that does not exist as physically real outside the telescope.

So I tried to find out what was happening on that "limb". It turns out that the events that happen on that "limb" are what they call "white light flares"!

What "limb"? The "ghost limb"? If you mean the "ghost limb" why can't you say "ghost limb", since "ghost limb" is what we are talking about. Or maybe you mean "true limb"? Say what you mean, it makes communication that much easier.

In this media image from HINODE of the solar chromosphere shows the loops sticking up through the photosphere.

The photosphere is not visible in any of the images you present in this post. You are doing exactly the same thing Mozina did, claiming to see the photosphere in images that do not include the photosphere. At this point you are just making things up out of your imagination.

 

[Reality Check]

So I tried to find out what was happening on that "limb". It turns out that the events that happen on that "limb" are what they call "white light flares"!
...

You are very incorrect in this post.

1. Nothing happens on that "limb" because that "limb" is an artifact of the detector.
   Lots happens on the limb of the Sun because that is an interesting area to image. Even more happens on the face of the Sun though.
2. By definition nothing can be seen more than a few 100 kilometers below the photosphere.
3. The TRACE detectors always saw light from events that were above the photosphere (see your error number 2). The name should be a hint to you: Transition Region and Coronal Explorer.

But nice paper with nothing to do with the topic:
[FONT=AdvSTP_TIMI][FONT=AdvSTP_TIMI]TRACE [/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]AND [/FONT][/FONT][FONT=AdvSTP_TIMI][FONT=AdvSTP_TIMI]YOHKOH [/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]OBSERVATIONS OF A WHITE-LIGHT FLARE
[/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]

[FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]
We present observations of a large solar white-light flare observed on 2001 August 25, using data from the [/FONT][/FONT][FONT=AdvSTP_TIMI][FONT=AdvSTP_TIMI]Transition Region and Coronal Explorer [/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]([/FONT][/FONT][FONT=AdvSTP_TIMI][FONT=AdvSTP_TIMI]TRACE[/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]) white-light channel and [/FONT][/FONT][FONT=AdvSTP_TIMI][FONT=AdvSTP_TIMI]Yohkoh[/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]/HXT. These emissions
are consistent with the classic type I white-light flare mechanism, and we find that the enhanced white-light emission observed by [/FONT][/FONT][FONT=AdvSTP_TIMI][FONT=AdvSTP_TIMI]TRACE [/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]originates in the chromosphere and temperature minimum regions via nonequilibrium hydrogen ionization induced by direct collisions with the electron beam and by backwarming of the lower atmosphere. The three flare kernels observed in hard X-rays and white light are spatially associated with magnetic separatrices, and one of the kernels is observed to move along a magnetic separatrix at 400 km s[/FONT][/FONT]
[FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]1[/FONT][/FONT][FONT=AdvSTP_TIMR][FONT=AdvSTP_TIMR]. This is evidence in favor of particle acceleration models, which energize the electrons via magnetic reconnection at magnetic separators.
[/FONT][/FONT]

Are you going to cite evey paper that references Handy, B. N., et al. 1999, Sol. Phys., 187, 229 when they use the Handy method of removing the detector artifact?​

[/FONT]​

[/FONT]​

 

[brantc]

The brightening is probably not real on the sun, but real only as an optical artifact, (a "ghost"). Like RC says, just read the figure caption: "Panel b shows the prominence as loop-shaped emission at 1216 Å, where the bright spot below the northern leg is, most likely, an UV continuum brightening on the ghost limb that appears ~2" above the true limb (Handy et al. 1999, their Fig. 5)."

The "ghost limb" is called a GHOST because it is not real on the sun, but rather an artifact of the optics in the telescope. So in the sense of being physically real on the sun, no it is not. The authors did not put that image in the sequence just because they "thought it was interesting to include", but because all of the other images are RHESSI X-ray images, and this one is the only TRACE UV image they have. The X-ray & UV correlation is potentially informative, and indeed the flare does show up in the TRACE image. But the bright blob on the limb does not show up in any of the RHESSI images.

From the paper. "Selected TRACE 1216 °A (panel b) and 195 °A (other panels) maps labeled by their exposure intervals during Phase I.
Superimposed are RHESSI PIXON image contours at 3–6 keV integrated in 40 s intervals, whose central times coincide with those of the
corresponding TRACE maps."

So they are all TRACE images with RHESSI contours superimposed.

Why would the authors say "it must be some form of limb brightening"??
That means they think their correction is working and that the "ghost limb" is some form of limb brightening.
No amount of squirming around is going to change that.

The blob is an optical artifact???? And pray tell, how does that happen???
And wouldnt random blobs screw up everything???
And what does RHESSI detect?? (Energy Range ~3 keV - ~17 MeV)

Would you expect to see these energy particles from a white light flare??

Sorry. Its a white light flare. And its UV continuum. So that means its happening right above the photosphere. In the HINODE images that I linked to, if you had bothered to go look, shows the top of the photosphere looking down into a sunspot from above the sun... So that means the white light flares are happening below the transition layer between the photosphere and the chromosphere..

The are 2 issues. The image is shifted "up" by 2 degrees. And there is channel contamination.
Neither one of these would lead to unknown dynamic objects(blobs) appearing in the telescope.

They are real objects. They are either in the wrong place or show up in the wrong channel.
Now if that ghost blob is a real object shifted up then its happening on the solar surface(you probably dont like that idea). But it certainty is not from channel contamination.

 

[Reality Check]

The are 2 issues. The image is shifted "up" by 2 degrees. And there is channel contamination.
Neither one of these would lead to unknown dynamic objects(blobs) appearing in the telescope.

There are artifacts from the properties of the telecope that are appearing in the images. That is what the Handy, B. N., et al. 1999, Sol. Phys., 187, 229 paper tries to remove. They are not completely successful thus the ghosting of the limb by contamination persists.

Liu et al in the paper Episodic X-ray Emission Accompanying the Activation of an Eruptive Prominence: Evidence of Episodic Magnetic Reconnection do not even try to remove the contamination.

I see no mention that the image is "shifted "up" by 2 degrees" in this paper.

• Where is this mentioned?
• Relative to what?

They are real objects. They are either in the wrong place or show up in the wrong channel.
Now if that ghost blob is a real object shifted up then its happening on the solar surface(you probably dont like that idea). But it certainty is not from channel contamination.

They are real objects in the detector, i.e. the detector really took these images and the light did come from the Sun.
They are not real objects on the Sun, i.e. there is no blob actually on the Sun.

It is most likely from "channel contamination" as described in Handy, B. N., et al. 1999 and stated by the authors of this paper:

"Panel b shows the prominence as loop-shaped emission at 1216 Å, where the bright spot below the northern leg is, most likely, an UV continuum brightening on the ghost limb that appears ~2" above the true limb (Handy et al. 1999, their Fig. 5)."

IMO the appearance of a blob in the image is easy to understand. They are taking an image of a prominence i.e. a loop. At a point on the loop the contamination dominates - I expect because of changes in plasma temperature. Thus a blob appears.

 

[Reality Check]

Missed this bit:

The blob is an optical artifact???? And pray tell, how does that happen???
And wouldnt random blobs screw up everything???
And what does RHESSI detect?? (Energy Range ~3 keV - ~17 MeV)

• The blob is an optical artifact.
• Because it is a ghosting of the image of a loop.
• The image contamination is not random - it happens when the 1500A light bleeds into the 1200A band that the astronomers wan to detect.
• Obviously this does not screw everything up. There seem to be only a handful of papers that mention the contamination but I expect that there are more out there.
• RHESSI detects X-rays.

 

[Tim Thompson]

The Solar "Ghost Limb" Is An Optical Artifact VII

The authors did not put that image in the sequence just because they "thought it was interesting to include", but because all of the other images are RHESSI X-ray images, and this one is the only TRACE UV image they have.

So they are all TRACE images with RHESSI contours superimposed.

OK, I stand corrected on that. Careless reading on my part.

Why would the authors say "it must be some form of limb brightening"??
That means they think their correction is working and that the "ghost limb" is some form of limb brightening.
No amount of squirming around is going to change that.

No, that does not mean they think that the correction is working and that the "ghost limb" is some form of limb brightening. No squirming required, it's really quite obvious. Just go back to the original paper by Handy, et al., 1999 (PDF link & NASA/ADS link). They say, on page 360, "The correction mechanism described in this paper is able to remove part of the ghosted limb, but it is evident that corrected limb images are still not right. What is left is evidently some form of limb brightening that is not corrected by this method.". So the authors of the Liu, et al., paper are simply repeating what Handy, et al., already said, namely that the correction method does not work completely, that it does not remove all of the ghosted limb, and that there is remaining contamination from limb brightening. I have also addressed these issues in my earlier posts The Solar "Ghost Limb" Is An Optical Artifact III and The Solar "Ghost Limb" Is An Optical Artifact IV.

The blob is an optical artifact???? And pray tell, how does that happen???

Easy. We already know that the ghost limb is an optical artifact in its entirety. The blob sits right on top of that which we know to be an optical artifact. Now, Liu, et al., did not say that the blob was definitely an optical artifact. What they did say is "... the bright spot below the northern leg is, most likely, an UV continuum brightening on the ghost limb ... ". That's "most likely", not definitely, and it's a perfectly reasonable call. Since it sits right on top of the artificial ghost limb, how do you know that it is not part of that artificial (i.e., not real) limb? The entire ghost limb visible in panel b of figure 2 in Liu, et al., is invisible in all of the 194 Å images. So is the blob invisible in all of the 194 Å images. So what justification does anyone have for claiming that the blob is physically real? Anyone with experience using any experimental device knows quite well that just because something shows up in the data stream does not guarantee that it has any physical reality outside the data stream itself. Just because it is observed in only one image does not make it real, and the fact that it coincides with a known artifact weakens any claim for reality. So, since the blob shows up in only one place on only one image, the authors of Liu, et al., properly assume it is an artifact. Had it made itself visible in other images, they might well not have made that assumption.

And wouldnt random blobs screw up everything???

Of course they would. But we are not talking about random blobs (plural). Rather, we are talking about one single non-random blob (singular). There is quite a difference.

And what does RHESSI detect?? (Energy Range ~3 keV - ~17 MeV)

So what? Look at the X-ray (RHESSI) contours in panels a,b & c in figure 2 of Liu, et al. The leading bright TRACE blob is detected by RHESSI in all 3 cases. However, the trailing bright blob in panel b is not detected. Why is that? Why should RHESSI detect the leading blob consistently, but not the trailing blob (which appears by the way at only one wavelength and in only one panel)? One more reason to believe that the trailing blob is not real on the sun.

Would you expect to see these energy particles from a white light flare??

Well, we are talking about detecting X-rays. From a white light flare? Why not? See, e.g., Fletcher, et al., 2007 or Chen & Ding, 2005.

Sorry. Its a white light flare.

OK. If it's a white light flare, show us white light images of it. But even if it is a white light flare, so what? What difference does that make? What does that have to do with with the nature of the "ghosted limb" in TRACE images, the one we are talking about?

In the HINODE images that I linked to, if you had bothered to go look, shows the top of the photosphere looking down into a sunspot from above the sun ...

I looked at every single image you liked to. All of them. The photosphere is not visible at all in any of those images.

The are 2 issues. The image is shifted "up" by 2 degrees. And there is channel contamination.
Neither one of these would lead to unknown dynamic objects(blobs) appearing in the telescope.

The offset is 2 arcseconds not 2 degrees; I already corrected you on this once before (The Solar "Ghost Limb" Is An Optical Artifact IV). Either or both of those could in fact easily lead to unknown dynamic objects appearing in the telescope. Any competent observer would be very aware of this. However, the point is irrelevant to our discussion, as there is no unknown dynamic object appearing in the images of Liu, et al. Rather, there is one static object (it is visible in only one frame) seen in the images, which coincides with a known optical artifact, does not show up in the 194 Å images, and does not show up in the RHESSI X-ray contours. In the absence of any additional evidence to the contrary, any competent observer would & should assume that the object is an artifact of the data stream, not a physically real object outside the telescope.

Now if that ghost blob is a real object shifted up then its happening on the solar surface (you probably dont like that idea). But it certainty is not from channel contamination.

Well, that's a pretty big if. All of the evidence indicates clearly that it is an artifact. But of course, there is a chance that it is not (remember "most likely"). Still, if it is real, it could be photospheric, so what? Why would that bother anybody? It's just a blob detected at one wavelength. It would take a lot more work than that to demonstrate a reason to be bothered.