Starship Asterisk*

Orange Sun Simmering

Explanation: Even a quiet Sun can be a busy place. And over the deep Solar Minimum of the past few years, our Sun has been unusually quiet. The above image, taken last week in a single color of light called Hydrogen Alpha and then false colored, records a great amount of detail of the simmering surface of our parent star. The gradual brightening towards the Sun's edge in this color-inverted image, called limb darkening, is caused by increased absorption of relatively cool solar gas. Just over the Sun's edges, several prominences are visible, while two prominences on the Sun's face are seen as light streaks just above and right of the image center. Two particularly active areas of the Sun are marked by dark plages. In contrast to recent quiet times, our Sun is moving toward Solar Maximum, and for years will likely appear much more active.

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It's 10 pm here in Hawaii and no one has posted on this yet. How sweet it is to open this up. I will say this: Is there any other star as perfect as our own? Really, what could possibly be better. Or is it the case of a child thinking his/her mother is the most beautiful person in the world? Nice picture.

hstarbuck wrote:I will say this: Is there any other star as perfect as our own? Really, what could possibly be better.

We're lucky to have it!

http://asterisk.apod.com/vie ... 29&t=19630

I just can't live without it.

Hi all, I am new to the message boards here but have been following APOD for over a year or so. I have a question about solar cycles. When did cycle 23 end, and 24 start? I read the link from New Scientist, but was not really clear on what the current situation is. Is there even a clear-cut distinction between the two cycles right now? Thanks!

Can someone explain how this image was made?

I get that it was taken with an H-alpha filter, but how was it then "false-colored" and "color inverted?" Were two other identical images used but the brightness/contrast changed for each and were then merged as an "RGB?"

Mizzou wrote:Hi all, I am new to the message boards here but have been following APOD for over a year or so. I have a question about solar cycles. When did cycle 23 end, and 24 start? I read the link from New Scientist, but was not really clear on what the current situation is. Is there even a clear-cut distinction between the two cycles right now? Thanks!

Hi Mizzou,

Solar Cycle 24 officially started when:
"a magnetically reversed, high-latitude sunspot, dubbed as number 981, was first observed" on January 4, 2008.

http://wattsupwiththat.com/2008/01/04/solar-cycle-24-has-officially-started/ wrote: Solar Cycle 24 has officially started
Posted on January 4, 2008 by Anthony Watts

<<Solar physicists have been waiting for the appearance of a reversed-polarity sunspot to signal the start of the next solar cycle.
The signal for the start of a new cycle is sighting a particular kind of sunspot. That wait is over.

A magnetically reversed, high-latitude sunspot, dubbed as number 981, emerged on the surface of the sun today.
This reversed polarity sunspot today marks the beginning of Solar Cycle 24 and the sun’s return back to Solar Maximum.

New cycle sunspot: South magnetic pole precedes North magnetic pole in northern hemisphere sunspot

Old cycle sunspot: South magnetic pole precedes North magnetic pole in southern hemisphere sunspot
................................................................
This from ESA may help everyone understand the transition:

• With the next solar cycle this [sunspot magnetic] orientation is flipped in both hemispheres, as the Sun’s global magnetic field reverses its orientation. As a new cycle begins, the number of sunspots with the reverse orientation will increase and the ones with the orientation of the old cycle will decrease in number. In the transition period they can both occur on the Sun, as the two cycles have no sharp boundary and overlap

.>>

http://en.wikipedia.org/wiki/Solar_cycle wrote: Time vs. solar latitude diagram of the radial component of the solar magnetic field, averaged over successive solar rotation. The "butterfly" signature of sunspots is clearly visible at low latitudes. Diagram constructed (and regularly updated) by the solar group at NASA Marshall Space Flight Center.

Hi,
Great image, but at first look there was one of Snoopys friends lookin back @ me.
Once seen, can't be unseen...............

SavEagle wrote:Can someone explain how this image was made?

I get that it was taken with an H-alpha filter, but how was it then "false-colored" and "color inverted?" Were two other identical images used but the brightness/contrast changed for each and were then merged as an "RGB?"

I'm happy to answer. This image is captured with a monochrome camera so all the data recorded is B&W. It is prepared from two images at two different exposure settings that are merged into a final composite - one is optimized for the disk of the sun, the other for the fainter prominences at the limb. The prominences and sky background are not inverted, but the brightness is increased to show the faintest reaches of the prominences. The disk detail is inverted (ie, a negative portrayal rather than positive). This accounts for the limb "lightening" and the fact that plages are dark and filaments, light.

The colorization is applied at the end of the process. All of these effects are accomplished using layers in Adobe Photoshop.

hope that helps!
clear skies,
Alan Friedman
http://www.avertedimagination.com

The colorization is applied at the end of the process. All of these effects are accomplished using layers in Adobe Photoshop.

So, just to clarify:
You don't make a color merged image with three separate images but instead just use the two images and make individual layers within Photoshop to play with the colors?
Pretty neat! Beautiful photo. I will most certainly be showing this to my Astronomy Labs.

The gradual brightening towards the Sun's edge in this color-inverted image, called limb darkening

You're just messing with us now, aren't you? This came from the Ministry of Truth, didn't it? Brightening is darkening, war is peace, freedom is slavery, ignorance is strength. I get it. I think. Or not.

markcant wrote:You're just messing with us now, aren't you? This came from the Ministry of Truth, didn't it? Brightening is darkening, war is peace, freedom is slavery, ignorance is strength. I get it. I think. Or not.

APOD wrote:The gradual brightening towards the Sun's edge in this color-inverted image, called limb darkening

Question -- If you have a pair of pears, how many pears do you have?
Question -- If you have a pair of pears, how many pairs do you have?

Isn't the english language fun? Now that you've read it, Speak it to some one and see what you get for a reply.

beyond wrote:Question -- If you have a pair of pears, how many pears do you have?
Question -- If you have a pair of pears, how many pairs do you have?

Pare a pair of pears and prepare the peels to appeal to Pierre.

neufer wrote:Pare a pair of pears and prepare the peels to appeal to Pierre.

Or even to the au pair of Père Pierre.

I never understood parity too well!

I think it is a superb image. A single image like this is for me far better than using videos for an APOD.

SavEagle wrote:

The colorization is applied at the end of the process. All of these effects are accomplished using layers in Adobe Photoshop.

So, just to clarify:
You don't make a color merged image with three separate images but instead just use the two images and make individual layers within Photoshop to play with the colors?
Pretty neat! Beautiful photo. I will most certainly be showing this to my Astronomy Labs.

That's right - the two exposures are colorized in separate layers in Photoshop using the Hue/Saturation tool. I'm glad you enjoyed the image!

What a beautiful Solar image! A false color version of a false-color producing filter (H-alpha).

Reversing it makes it all that more impressive, though it isn't the best image to bring up the topic of limb darkening.

Helio George wrote:What a beautiful Solar image! A false color version of a false-color producing filter (H-alpha).

A Ha filter doesn't produce a false color image, it produces a monochromatic image. Any "false color" comes from the choice of scale used to display the data. This is no different from any filter used to obtain image data.

Boy - I'll tell ya -- it sure is fun to dangle some bait in this forum and see what takes it!!
I forgot i had one more bait in the can.

Question -- if you have a pair of pairs, how many pairs do you have a pair of

beyond wrote: Question -- if you have a pair of pairs, how many pairs do you have a pair of

To two tutus too. Toodeloo.

hstarbuck wrote:It's 10 pm here in Hawaii and no one has posted on this yet. How sweet it is to open this up. I will say this: Is there any other star as perfect as our own? Really, what could possibly be better. Or is it the case of a child thinking his/her mother is the most beautiful person in the world? Nice picture.

No, it truely is a perfect star. Created and put in place so that we can live!

beyond wrote:Boy - I'll tell ya -- it sure is fun to dangle some bait in this forum and see what takes it!!
I forgot i had one more bait in the can.

Question -- if you have a pair of pairs, how many pairs do you have a pair of

Answer-- One pair.