# Large sunspot visible

• Stargazing
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over this week a very large single spot has been traversing the solar disk
will still be visible for another 3-4 days

This was taken today .. 13 Apr 2016
f/l 800mm, 500th sec, ISO 200, f7.1 (plus whatever the solar filter added lots and lots )
The filter ( commercial one that I use) cuts out around 99.99% of the light from the sun

cheers
Dave

ProfuselyQuarky, DrClaude, Borg and 4 others

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Wow. That thing must be huge. Several times the Earth's diameter, right?

Nice photography.

davenn
Looks like something that should be checked out by a doctor

sophiecentaur, Flyx, Bystander and 2 others
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Wow. That thing must be huge. Several times the Earth's diameter, right?

Nice photography.

thanks, phinds It's my 150 - 500mm tele-zoom on my Pentax K5 crop sensor camera = somewhere around 840mm equivalent f/l on a full frame camera

Yes, They are saying around 2-3 Earth sizes

D

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Looks like something that should be checked out by a doctor

Haha ... hmmmm does have that melanoma look to it huh

Dave

Got a few good images this morning- this one is 'normal', using only an ND4 metallic filter, original is 1570 x 1570 pixels: 800mm f/8, 1/200s ISO 80

And a zoom on the sunspot, using the red channel of an image taken with ND4 + Schott BG3 filters (I don't own any proper line filters):

I think davenn is upside down :)

davenn and DrClaude
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I think davenn is upside down :)
Yes, I have long suspected that might be the reason ...

davenn
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Dave
Got a few good images this morning- this one is 'normal', using only an ND4 metallic filter, original is 1570 x 1570 pixels: 800mm f/8, 1/200s ISO 80

nice one Andy, thankyou for sharing and adding to the images

And a zoom on the sunspot, using the red channel of an image taken with ND4 + Schott BG3 filters (I don't own any proper line filters):

nor do I, a narrow band solar telescope has been on my to buy list for many, many years ...
high price for minimal use has always been the stopper

Andy Resnick said:
I think davenn is upside down :)

Yes, I have long suspected that might be the reason ...

hahaha

Dave

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Where do you guys get those filters? Do they come in standard sizes and fittings for most camera lenses? I would like to get some practice before next year's eclipse.

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Where do you guys get those filters? Do they come in standard sizes and fittings for most camera lenses? I would like to get some practice before next year's eclipse.

have a look at my latest post in that eclipse thread, I have a link

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From today's edition of spaceweather.com

Giant sunspot AR2529 is making noise, and it sounds like static. On April 14th, amateur astronomer Thomas Ashcraft heard a gentle crescendo of noise emerge from the loudspeaker of his shortwave radio telescope in New Mexico. "It was a Type III radio burst from the sun," he says. Click to listen (the static surges about 20 seconds into the audio file):

Type III radio bursts are caused by solar flares. Electrons accelerated by magnetic explosions race through the sun's atmosphere, causing a ripple of plasma waves and radio static. Sunspot AR2529 has been crackling with C-classflares, almost non-stop, and these are apparently the source of the static.

"The burst was recorded in stereo using two separate short wave receivers, one tuned at 20.030 MHz and the other at 21.119 MHz. Best listened to with headphones," says Ashcraft.

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From today's edition of space weather.com

BIG SUNSPOT ERUPTS:
Surprise! Quiet sunspot AR2529 isn't so quiet, after all. The heart-shaped active region erupted on April 18th (00:39 UT), producing a strong M6.7-class solar flare. NASA's Solar Dynamics Observatory recorded the flare's extreme ultraviolet flash:

A pulse of UV radiation from the flare ionized the top of Earth's atmosphere. This, in turn, disrupted shortwave radio communications over the daylit side of our planet. Mariners, aviators, and ham radio operators around the Pacific Ocean may have noticed fading signals at frequencies below ~15 MHz. A NOAA blackout map shows the frequencies and territories affected.

More M-class flares are possible in the days ahead. AR2529 has developed a 'beta-gamma' magnetic field that harbors plenty of energy for this kind of explosion. Although the sunspot is no longer directly facing Earth, it can still affect our planet by causing radio blackouts and glancing-blow CMEs.

OmCheeto
Suman Saha
Is that something related to alien?

Gold Member
Is that something related to alien?

?

Oh. Now I get it. But it was "Alien Resurrection", and not "Alien".

...

Suman Saha
?

Oh. Now I get it. But it was "Alien Resurrection", and not "Alien".

...
What?

Gold Member
From today's edition of spaceweather.com:

BIG SUNSPOT DEPARTS:
Yesterday, giant sunspot AR2529 unleashed a powerful M6.7-class solar flare. Today, the sunspot is leaving. AR2529 is approaching the sun's western limb where it will soon disappear from view. Maximilian Teodorescu sends this parting shot from Dumitrana, Romania:

"I took this picture using a solar-filtered 8 inch telescope and an ASI 174MM digital video camera," says Teodorescu.

When AR2529 leaves the solar disk, the odds of a geo-effective flare will plummet and the solar cycle can continue its plunge toward Solar Minimum.

georgir and OmCheeto
1oldman2
unfortunately won't see this one in Oz
That is unfortunate!, I would be happy to trade places with you for the event.

davenn
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I seem to remember reading that sun spots occur in pairs. Where would be the other half? Or is it all within the same region, in this case?
A bit of luck. The other day, I was getting my finder scope ready for projecting an image of the Sun on a white card, in an attempt to see the transit of Mercury next week and I saw that enormous sunspot. Just a single one and very impressive! I should look more often. Then I happened to look on the astronomy forum and saw this thread title. The only other ones I have seen have been really feeble little blemishes compared with that big mother.

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I seem to remember reading that sun spots occur in pairs. Where would be the other half? Or is it all within the same region, in this case?

in this case all within the same region ... if you look at the close ups of the photos by Andy and myself and then the commercial image from dotini, you can see that the main spot is segmented

A bit of luck. The other day, I was getting my finder scope ready for projecting an image of the Sun on a white card, in an attempt to see the transit of Mercury next week and I saw that enormous sunspot. Just a single one and very impressive! I should look more often. Then I happened to look on the astronomy forum and saw this thread title. The only other ones I have seen have been really feeble little blemishes compared with that big mother.

well done ... good to hear you are getting the scope ready for the transit
Uh huh, was the biggest spot region I had seen for a very long time

you should invest in a solar filter ... maybe an astronomy shop near your location has one of these brands ...

I have 2 of them ... a smaller one that fits the telephoto lens for the camera ... used to take the image in post #1
and a much larger one the covers the whole front of the telescope, so that I can visually observe and if wanted,
do photography of the sun through the scope.
Many years ago, I used to do eyepiece projection from the scope onto paper and hand draw the spots
I would stop the light down from entering the scope by putting a piece of cardboard with a ~ 2 - 3" hole in it
rather than the full 8" aperture of the scope. This increased the F stop substantially and reduced the light and heat
intensity sufficiently to minimise the possibility of damage to the telescope optics.

Dave

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Oh, right. The multiple bits of that picture are obvious no I think about it.
you should invest in a solar filter
That's more than half what I paid for the 'scope! My life. Nice idea but. . . . . .
I found the Beehive Cluster tonight and a very faint blur which I think was the Pinwheel Galaxy. But the PG is right next to the big dipper so it won't be seen very often in your parts, I guess.
I could do the big f stop on the Dobs, I guess but I have heard so much about problems with the Sun roasting bits inside reflectors that I would need it stuck on very reliably.

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That's more than half what I paid for the 'scope! My life. Nice idea but. . . . . .

Those are AU$prices ... what make and model scope do you have ? They really are VERY GOOD emphasis intended I found the Beehive Cluster tonight and a very faint blur which I think was the Pinwheel Galaxy. But the PG is right next to the big dipper so it won't be seen very often in your parts, I guess. The pinwheel galaxy = M101 in Ursa Major ( the big dipper) never gets above our horizon I could do the big f stop on the Dobs, I guess but I have heard so much about problems with the Sun roasting bits inside reflectors that I would need it stuck on very reliably. an added advantage with increasing the f-stop is that it also improves the image sharpness for visual use to observing the sun, if you cannot afford a commercial solar filter, is to use a mylar survival blanket available from camping/outdoor stores only a few bucks/pounds ( your choice of currency) still stop down the aperture with a smaller hole, then across that hole use several layers ( 3 to 4 usually enough) it makes an effective visual and photographic filter for direct solar viewing I have often stretched several layers directly across the end of my camera telephoto lens and taped in place ... also works well Dave sophiecentaur and 1oldman2 1oldman2 for visual use to observing the sun, if you cannot afford a commercial solar filter, is to use a mylar survival blanket available from camping/outdoor stores Awesome! Thanks for the info. I had no idea. davenn Science Advisor Gold Member 2021 Award Awesome! Thanks for the info. I had no idea. you are welcome 1oldman2 Science Advisor Gold Member Those are AU$ prices ... what make and model scope do you have ?
I bought a sky watcher dobs 200p on eBay.
It looks like it has had an easy life and the optics seem to be lined up right. The two kit lenses are a bit naff, I think. I just bought a 2 inch 32mm Panavision SWA lens which is so much better. It's contrasty and crisp and pretty flat over the field. That beehive cluster was stunning with my eye flat against the eyepiece. I never realized that magnification isn't everything when looking at the sky. Structures are just as interesting as tiny details. Stellarium is my friend at the moment.
Of course, the Dobs lacks any screw adjustments for direction and I have started to learn how to star-hop, to get to stuff, even with the finder scope. The pinwheel galaxy is directly overhead and the altaz mount is a total pig at that angle; you have to get used to a completely non-cartesian idea of moving around a cartesian looking picture. The two degrees of freedom that you have, do really unexpected things with what you see and even with a right angle finder scope, you still have to lay on the ground to point it in the right sort of direction to start with.
All this is totally off - topic, of course.

davenn and Andy Resnick
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I bought a sky watcher dobs 200p on eBay.
It looks like it has had an easy life and the optics seem to be lined up right. The two kit lenses are a bit naff, I think. I just bought a 2 inch 32mm Panavision SWA lens which is so much better. It's contrasty and crisp and pretty flat over the field. That beehive cluster was stunning with my eye flat against the eyepiece.

if this is the beast ? ...
https://www.firstlightoptics.com/dobsonians/skywatcher-skyliner-200p-dobsonian.html

that should keep you out of trouble for some time

I never realized that magnification isn't everything when looking at the sky. Structures are just as interesting as tiny details.

indeed ! ... magnification is more important for planetary observing because of their small angular size
for most deep space objects, lower magnification is more important

Stellarium is my friend at the moment.
Of course, the Dobs lacks any screw adjustments for direction and I have started to learn how to star-hop, to get to stuff, even with the finder scope.

This is really important ! I spent the first 30 years of my amateur astro life star hopping and in those days using paper maps. It's the ONLY way to really get to know your way around the sky. It's a valuable skill. Even tho I have a GOTO ( controller guided) scope these days, it mainly gets used for being able to quickly get between objects I want to photo ... on my own or when I take a group out with me. For finding things like comets, nova etc, I still resort to my well learned star hopping skills

The pinwheel galaxy is directly overhead and the altaz mount is a total pig at that angle; you have to get used to a completely non-cartesian idea of moving around a cartesian looking picture. The two degrees of freedom that you have, do really unexpected things with what you see and even with a right angle finder scope, you still have to lay on the ground to point it in the right sort of direction to start with.

You will get used to it, you may find making a 0.5 metre high platform to sit the scope/ mount on eases the difficulty of use Last August, I bought a new camera for doing astrophotography, the Canon 700D, one of its major selling points to me is that it has a swivelling LCD panel, unlike my main camera, the Canon 5D MK3. Now I don't have to kink my neck/head into weird angle to try and see the screen when doing focussing etc, it is so much more fun to use

All this is totally off - topic, of course.

Was my thread, the main topic had been well discussed. I don't mind it going off track if it means I can pass on some encouragement for people to get out there and have some astro fun

cheers
Dave

sophiecentaur and 1oldman2
Gold Member
you may find making a 0.5 metre high platform to sit the scope/ mount on eases the difficulty of use
I was already considering that. It would make a 'decorative' seat for the garden when the Dobs was not there. Two for the price of one!

I have also considered how easy it might be to use a different base, with an inclined bearing to turn the Dobs mount into a polar mount. As I do not intend to cart the scope around the World, that base could be permanently fixed outside, pointing N/S and I would only need to take the scope barrel indoors. I can't imagine it would be possible just to park the Dobs on a sloping platform; the azimuth bearing wouldn't stand it. I have already found it inconvenient to keep up with Jupiter as it marches across my view, using both axes. (A pukka conversion to polar mount with Goto for my dobs is out of the question for a while - until I have made much better use of it)

davenn
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davenn, sophiecentaur and 1oldman2
1oldman2
Now that is a good example of perspective!

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Now that is a good example of perspective!
If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.

1oldman2
1oldman2
If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.
I have to claim total ignorance when it comes to this question. I'm pretty sure the image Dotini posted is from NASA's SDO so that would be tough to compete with from earth. I would think Dave, Russ, Dotini or Andy would be able to recommend the best case answer for choosing a filter.

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If I go the the expense of buying a solar filter for my 200mm Dobs, is that the sort of picture I should be expecting? That would mean an extra potential half days gazing every day.
Got that pic off Yahoo - was probably a pro level shot. Here's the site: https://www.yahoo.com/news/transit-mercury-producing-awe-inspiring-171007799.html

Solar gazing is probably best for a short time in the early morning after sunrise.

1oldman2