The Sun today - 2 images attached

[William Bottaci]

Hello, again
Today's Sun, and I won't be posting more as it becomes repetitive;
maybe just the odd unusual one. But today includes a large group, and
an improvement in processing.
In 2 weeks' time on the 23rd we'll be astronomical twilight for about
2 months; perhaps a good time to concentrate on our oft neglected
neighbours in our solar system.

Altitude 54º
Diameter 31º 40'
Distance 1.009 AU (we are closest in winter, January 3rd)

The weather this morning was clear with turbulence not so bad but
definitely there.

Canon R7 with RF 100-500mm L IS lens with x1.4 tele-extender (700mm),
f/10 1/200 sec, ISO 125), hand-held stabilised. Baader solar film
filter.

An improved processed combination of several jpg images and future
ones will be on multiple raw files.
Needs to be viewed at 100% size for the extra detail, and I think most
if not all browsers show a 'quick' degraded image unless downloaded.

Thank you for looking, William

=CanR7_029529_M2-160.jpg (180K)=
=CanR7_029529_M2-180_120.jpg (168K)=

[Roy Easto]

Thanks for this William. I looked with my naked eye through a full
aperture solar filter but couldn't quite make it out. It was easy to see
projected through binoculars though. Anyone seen it with the naked eye?

Roy

[William Bottaci]

Hello Roy
I always need to use sunglasses, sometimes 2 pairs, in addition to eclipse glasses or solar filter, then it's a lot easier. I could see the group but it wasn’t as obvious as with single spots even though they're smaller.
We should see more naked-eye soon as we're in the maximum phase of the solar cycle.

During Astrofest earlier this year I bought a newly designed linear binoviewer, one that does not change the focal length at all so can work with any (existing) telescope, no matter how short. It works by taking half the full light to each eye instead of the full half-light to each eye. It works, just differently. As it uses mirrors there's no extra focal length. Fortunately I was able to try them whilst there, some reading, and took a chance, with the option of a return even after use, and they were very competitively priced. Came with eyepieces, a superior design and proved to be. All Japanese designed.

I was alarmed by what I thought was a fault, but after some trials and testing it turned out to be no worse a feature than already exists with eyepieces and traditional binoviewers. The slight change in the way they are best used is what I do anyway. The one drawback is minor and does not apply to my circumstances, nor likely to anyone else.

The solar filter I bought with it fits both an 80mm telescope and telephoto lens with the same exact dimensions, even though the filter allows adjustment, coincidently is not required.
Viewing the sun through these is well worth it over just one eye; as is the moon and the larger planets.

Anyway, a digression from the Sun, but if you can use a pair of binoculars, I think it's the only way to see the sun now. Fortunately the views offer high contrast and I'm well pleased, as solar filters can be low contrast.

I have a pair of solar binoculars, x12, that allow me to 'keep in touch' still when there's just gaps in the cloud.
William

On Wed, 8 May 2024 at 19:43, 'Roy Easto' via croydonastro <croydo...@googlegroups.com> wrote:
Thanks for this William. I looked with my naked eye through a full aperture solar filter but couldn't quite make it out. It was easy to see projected through binoculars though. Anyone seen it with the naked eye?
Roy

2024-05-08

[drja...@aol.com]

Had a look just now 09:39 through the essential Baader safety film but otherwise naked eye.  Very surprised to see what must be the large sunspot and quite obvious.  Never seen anything before.

James

On 8 May 2024, at 20:43, William Bottaci <w.bo...@gmail.com> wrote:



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[William Bottaci]

Hello James
I'm glad you got to see this; it is really quite obvious. Depending on eyesight it can look like a large grey region or spot; I think for some it'll be easier than an individual spot. Well worth having a look if you get the chance.

I'm going to have another go at imaging it; there is value in seeing the change over one day, but it could take a couple of days to process as what I do now, though improved, is more involved and time consuming. Still, not as much as deepsky objects.
William

On Thu, 9 May 2024 at 09:40, 'drja...@aol.com' via croydonastro <croydo...@googlegroups.com> wrote:
Had a look just now 09:39 through the essential Baader safety film but otherwise naked eye.  Very surprised to see what must be the large sunspot and quite obvious.  Never seen anything before.
James

2024-05-08

[Roy Easto]

I looked today and could easily see the spot with the naked eye. The issue yesterday must have been that the Sun was low down and through light cloud. For the record I have a Thousand Oaks Optical type 2+ solar filter suitable for a 90mm Meade telescope.

Roy

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[drja...@aol.com]

Thanks William.

I've just been imaging too!  Very turbulent, and now getting hazy.  In a field of view containing just the large sunspot the turbulence looks like plasma flows in real time.  There is a very and active large prominence on the limb nearest the big sun spot.

James

Sent from my iPad

On 9 May 2024, at 10:10, William Bottaci <w.bo...@gmail.com> wrote:



--

[William Bottaci]

Hello, once more
Yesterday I spoke too soon; how was I to know we'd get two sunny days in a row?
Comparing consecutive days has value because we see both the rotation and development of the sunspots, so please find attached another 2 images with the same specifications, just a day later.

  Altitude      48º

  Diameter   31º 40'
  Distance    1.009 AU (we are closest in winter, January 3rd)

The weather this morning not so clear, high clouds though thin so I had to raise the ISO, and turbulence was worse.

Canon R7 with RF 100-500mm L IS lens with x1.4 tele-extender (700mm), f/10 1/200 sec, ISO 200, hand-held stabilised. Baader solar film filter.

An improved processed combination of several jpg images, which dealt with the turbulence, and the balance of brightness and contrast seems better.

Needs to be viewed at 100% size for the extra detail, and I think most if not all browsers show a 'quick' degraded image unless downloaded.

Thank you for looking, William

=CanR7_029565_M2-U-160.jpg (203K)=
=CanR7_029565_M2-U-180_120.jpg (194K)=

[William Bottaci]

Hello James, how did your imaging go?
Thanks for notifying us of the prominence. I managed to see it with a Lunt Ha 60mm and it's a beauty.

Here is one, that I'd like to say I took earlier, only I can't quite bring myself to do so...:
https://gong2.nso.edu/HA/hag/202405/20240509/20240509090342Lh.jpg

William

On Thu, 9 May 2024 at 11:53, 'drja...@aol.com' via croydonastro <croydo...@googlegroups.com> wrote:
Thanks William.
I've just been imaging too! Very turbulent, and now getting hazy. In a field of view containing just the large sunspot the turbulence looks like plasma flows in real time. There is a very and active large prominence on the limb nearest the big sun spot.
James

On Thu, 9 May 2024 at 11:26, 'Roy Easto' via croydonastro <croydo...@googlegroups.com> wrote:
I looked today and could easily see the spot with the naked eye. The issue yesterday must have been that the Sun was low down and through light cloud. For the record I have a Thousand Oaks Optical type 2+ solar filter suitable for a 90mm Meade telescope.
Roy

2024-05-09

Hello James
I'm glad you got to see this; it is really quite obvious. Depending on eyesight it can look like a large grey region or spot; I think for some it'll be easier than an individual spot. Well worth having a look if you get the chance.

I'm going to have another go at imaging it; there is value in seeing the change over one day (and a rare occurrence of two straight clear days) but it could take a couple of days to process as processing now, though improved, is more involved and time consuming. Still, not as much as deepsky objects.

=CanR7_029529_M2-U-160.jpg (180K)=
=CanR7_029529_M2-U-180_120.jpg (168K)=

[drja...@aol.com]

Hi William

We'd all like to say we'd taken that one!

Here is my effort so far.  I have some full disk data as well but other things summoned me away.   Lunt 60 as well with asi178 mono, 500 frames at gain 101 and 2.4ms from memory.  Autostakkert 3 and imppg.

James

Sent from my iPad

On 9 May 2024, at 18:24, William Bottaci <w.bo...@gmail.com> wrote:



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[drja...@aol.com]

Don't think the image was transmitted, so a second attempt

On 9 May 2024, at 18:52, drja...@aol.com wrote:

Hi William

[drja...@aol.com]

The large sunspot 3664 yesterday in close up.  Capture details as before but with 2.5x powermate and processed in Photoshop expetimentally, to give a 3d impression of roiling boiling plasma.

Sent from my iPad

On 9 May 2024, at 18:52, drja...@aol.com wrote:

Hi William

[William Bottaci]

Hello James, and you took the one that is even better, a very good result!
We're looking forward to seeing the whole disk images.
Thank you for sharing.
William

On Thu, 9 May 2024 at 18:52, 'drja...@aol.com' via croydonastro <croydo...@googlegroups.com> wrote:
Hi William
We'd all like to say we'd taken that one!
Here is my effort so far.  I have some full disk data as well but other things summoned me away.   Lunt 60 as well with asi178 mono, 500 frames at gain 101 and 2.4ms from memory.  Autostakkert 3 and imppg.

James



2024-05-09

[drja...@aol.com]

Thanks very much William.

As for the full disk, I put the video data (Thursday 8 May 2024) through the stacking software Autostakkert3!, to find almost all of it was below the quality of the few best frames.  I ended up processing just the best 10% of 1000 frames.  Maybe it was early morning haze.

This is my best effort, processed to suggest 'hot'. Though upside down, I have left it that way as it looks better to my eye.

 The bright ring outer is made up of 'spicules', dynamic jets of plasma around 300 km diameter, that rise at speeds between 15 and 100kms per second and then fall back in a few minutes. (Wikipedia).  

The obvious major sunspot group 3664 is very large and a product of the sun approaching its maximum activity in the solar intensity cycle.  This shows up in the current solar storms and Northern Light shows, created by several recent coronal mass ejections (totalling 7 billion tonnes of charged particles, according to Radio 4).  

I'm attaching my 'close up' monochrome image of the sunspot for reference (Lunt 60 at f20.7 with 2.5x Powermate).  Measuring its size needs to take account of the sun's curved surface and that the sunspot is increasingly foreshortened from left to right in the image.  The Solar Dynamics Observatory apparently produces flattened images which allow simple pixel counting of a sun spot relative to the full width.  I couldn't find them, nor any ready made estimates of either the width or area of 3664 but there must surely be some.

I think there is software to analyse an image of the sun properly.  But as a rough guide, the sun spot group, guessing where its edges are and ignoring foreshortening, measures about 17% of the maximum linear full width shown in the full disk image (an underestimate of the true curved surface length).

The diameter of the sun is 1392 million kilometres, giving an estimate of about 230 million kilometres for the width of the 3664 group.  The Earth's diameter is a mere 12,800km at the equator.  This suggests the sunspot is 18,000 times wider than the Earth.  

This estimate is very rough and ready, but does it matter?   It's way bigger than the Earth.   Of course if it would be interesting to see the answer if anyone can do it properly.

James

On 10 May 2024, at 09:44, William Bottaci <w.bo...@gmail.com> wrote:



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[William Bottaci]

Hello James, thank you for the images; very nice work, and good to know features of the sun.
Atmospheric seeing, turbulence, never good in this country, and of course worse when closer to the horizon.
You show it as they see it south of the equator.

To 'flatten' a sphere a little spherical geometry is required; the sine or cosine function is a good starting point as it relates or maps the angle with the distance, so as you measure from the centre of the sun to the limb you add (which is stretching like a rubber sheet) the amount as given by a formula using these functions. I'm thinking back to the 'log tables' in schools before calculators came along.
Map projections use this. Easier with the sun as it's remarkably round, the earth being ellipsoidal needs more complex formulae if going a long distance. Navigators on early aircraft had to do this. Remember Norman Tebbit?

A slight typo in the diameter of the sun, you missed a decimal point, 1.392, so 18 times bigger (you're keeping us on our toes :).

Thank you for sharing.
William

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