4 ms·

Time lapse of this week's large sunspot

51 points by gattr 3y ago

gattr 3y ago
Captured with a 180 mm diameter telescope. The animation spans 20 minutes, with 20-second intervals between frames. edit: Also available as a smaller-sized H264 MP4 [1]. [1] https://www.cloudynights.com/gallery/image/182808-ar-3354-animation-in-wl/ https://www.cloudynights.com/gallery/image/182808-ar-3354-an...
- jcims 3y ago
  Nicely done! Any idea what the field of view is?
  - gattr 3y ago
    Thanks! The horizontal FOV is around 5 arcminutes. The granules (the bright convection cells comprising most of the image around the sunspots) are about 1000 km across on average.
    - jcims 3y ago
      That’s wild!
    - keepamovin 3y ago
      What are the features apart from the granules? The black feathers rimming the totally dark areas? What are these up close?
      - jcims 3y ago
        Wikipedia has it has a pretty great article on sunspots. https://en.m.wikipedia.org/wiki/Sunspot https://en.m.wikipedia.org/wiki/Sunspot Your question got me curious, those are called penumbral filaments. Their form has to do with the orientation of the magnetic field relative to the surface of the sun.
- thghtihadanacct 3y ago
  Nice. Now this is quality content. GJ
- dylan604 3y ago
  I have long decided that my next major astro purchase would be for solar observation, so I'm very jelly!! The closest I've gotten is being a little hacker and written a wget script to download from SOHO, but I feel like that's cheating compared to you ;-)
  - gattr 3y ago
    For photospheric observations/imaging like here (also called "white light") you only need the inexpensive Baader AstroSolar film fitted onto your existing instrument (telescope, binoculars, photographic lens). ...but beware the unrelenting "I need bigger aperture and to travel to better-seeing locations".
    - dylan604 3y ago
      >..but beware the unrelenting "I need bigger aperture and to travel to better-seeing locations". that's one of the compelling reasons to get into solar observations. if we ever get to a point of worrying about light pollution blocking our view of the sun... my current astro rig is specific for deep sky objects, and is a very wide angle telescope. when i observe the moon, maybe 50% of the FOV is the moon, so i want a different scope for viewing solar system objects that I can then attach said solar filters.
jcims 3y ago
Astrobin is an amazing resource. Like Flickr for astronomers https://www.astrobin.com/search/?d=i https://www.astrobin.com/search/?d=i It's amazing what some people are able to do with relatively modest (and not-so-modest) equipment.
helij 3y ago
This one was visible with naked eyes using appropriate white light filters.
xnx 3y ago
The heavy smoke in the Midwest made it easily viewable through phone camera zoom.
- paulkrush 3y ago
  Yep,us too. We saw it with the naked eye. There was a rather odd looking non-shining orange ball in the sky with a dot in the center viewed from Wisconsin Dells.
nomel 3y ago
What's the scale like? For example, how big are the, fairly uniform looking, bumps in the background?
- cratermoon 3y ago
  Those bumps are convection cells in the Sun's photosphere, called "granules"[1]. They roughly 2/3rds the east-west length of the US: Richmond, Virginia to Phoenix, Arizona. 1 https://en.wikipedia.org/wiki/Solar_granule https://en.wikipedia.org/wiki/Solar_granule
RIMR 3y ago
In case you were curious about the scale of this thing: https://www.astrobin.com/full/ofq7gz/0/ https://www.astrobin.com/full/ofq7gz/0/
ftxbro 3y ago
is this bad or good
lucb1e 3y ago
Besides some movement in the tiny individual cells, the black spots are not moving, not sure what the timelapse is trying to show. I looked for some 30 seconds, waiting for the bigger structures to start moving at all, before noticing that it seems to be looping every 3 seconds or so (not sure, the site lacks a seek bar or other duration indicator). Nothing happens that I can tell. What are we supposed to be seeing here?
- gattr 3y ago
  (For some more details, see also [1].) The bright boiling granules (comprising most of the image) show photosphere convection. There's also the inward movement of the tips of penumbral filaments (which surround the dark sunspot cores), though the material in them flows outwards ([2]). Note how granules get deformed in constrained areas before the two major sunspots. All this can be seen in a "somewhat" higher resolution on time lapses from professional telescopes, e.g., [3] (from the 1 m diameter Swedish Solar Telescope). [1] https://en.wikipedia.org/wiki/Sunspot https://en.wikipedia.org/wiki/Sunspot [2] https://en.wikipedia.org/wiki/Evershed_effect https://en.wikipedia.org/wiki/Evershed_effect [3] https://ttt.astro.su.se/isf/gallery/movies/2010/ https://ttt.astro.su.se/isf/gallery/movies/2010/
thulle 3y ago
Looks like melanoma.
nonrepeating 3y ago
One of my favorite facts about sunspots is, they’re still in extremely bright, they’re only dark due to contrast. An electric arc against a sunspot would look black by comparison (given typical logarithmic brightness measurement).
- gattr 3y ago
  You're right, here are some numbers: - photosphere temperature: 5870 K - sunspot umbra temperature: 3000-4500 K Per Stefan-Boltzmann law, this can make the photosphere up to (5870/3000)⁴ ≈ 15 times brighter.

51 points by gattr 3y ago

Captured with a 180 mm diameter telescope. The animation spans 20 minutes, with 20-second intervals between frames. edit: Also available as a smaller-sized H264 MP4 [1]. [1] https://www.cloudynights.com/gallery/image/182808-ar-3354-animation-in-wl/ https://www.cloudynights.com/gallery/image/182808-ar-3354-an...

jcims 3y ago
Nicely done! Any idea what the field of view is?
- gattr 3y ago
  Thanks! The horizontal FOV is around 5 arcminutes. The granules (the bright convection cells comprising most of the image around the sunspots) are about 1000 km across on average.
  - jcims 3y ago
    That’s wild!
  - keepamovin 3y ago
    What are the features apart from the granules? The black feathers rimming the totally dark areas? What are these up close?
    - jcims 3y ago
      Wikipedia has it has a pretty great article on sunspots. https://en.m.wikipedia.org/wiki/Sunspot https://en.m.wikipedia.org/wiki/Sunspot Your question got me curious, those are called penumbral filaments. Their form has to do with the orientation of the magnetic field relative to the surface of the sun.
thghtihadanacct 3y ago
Nice. Now this is quality content. GJ
dylan604 3y ago
I have long decided that my next major astro purchase would be for solar observation, so I'm very jelly!! The closest I've gotten is being a little hacker and written a wget script to download from SOHO, but I feel like that's cheating compared to you ;-)
- gattr 3y ago
  For photospheric observations/imaging like here (also called "white light") you only need the inexpensive Baader AstroSolar film fitted onto your existing instrument (telescope, binoculars, photographic lens). ...but beware the unrelenting "I need bigger aperture and to travel to better-seeing locations".
  - dylan604 3y ago
    >..but beware the unrelenting "I need bigger aperture and to travel to better-seeing locations". that's one of the compelling reasons to get into solar observations. if we ever get to a point of worrying about light pollution blocking our view of the sun... my current astro rig is specific for deep sky objects, and is a very wide angle telescope. when i observe the moon, maybe 50% of the FOV is the moon, so i want a different scope for viewing solar system objects that I can then attach said solar filters.

jcims 3y ago

Astrobin is an amazing resource. Like Flickr for astronomers https://www.astrobin.com/search/?d=i https://www.astrobin.com/search/?d=i It's amazing what some people are able to do with relatively modest (and not-so-modest) equipment.

helij 3y ago

This one was visible with naked eyes using appropriate white light filters.

xnx 3y ago

The heavy smoke in the Midwest made it easily viewable through phone camera zoom.

paulkrush 3y ago
Yep,us too. We saw it with the naked eye. There was a rather odd looking non-shining orange ball in the sky with a dot in the center viewed from Wisconsin Dells.

nomel 3y ago

What's the scale like? For example, how big are the, fairly uniform looking, bumps in the background?

cratermoon 3y ago
Those bumps are convection cells in the Sun's photosphere, called "granules"[1]. They roughly 2/3rds the east-west length of the US: Richmond, Virginia to Phoenix, Arizona. 1 https://en.wikipedia.org/wiki/Solar_granule https://en.wikipedia.org/wiki/Solar_granule

RIMR 3y ago

In case you were curious about the scale of this thing: https://www.astrobin.com/full/ofq7gz/0/ https://www.astrobin.com/full/ofq7gz/0/

ftxbro 3y ago

is this bad or good

lucb1e 3y ago

Besides some movement in the tiny individual cells, the black spots are not moving, not sure what the timelapse is trying to show. I looked for some 30 seconds, waiting for the bigger structures to start moving at all, before noticing that it seems to be looping every 3 seconds or so (not sure, the site lacks a seek bar or other duration indicator). Nothing happens that I can tell. What are we supposed to be seeing here?

gattr 3y ago
(For some more details, see also [1].) The bright boiling granules (comprising most of the image) show photosphere convection. There's also the inward movement of the tips of penumbral filaments (which surround the dark sunspot cores), though the material in them flows outwards ([2]). Note how granules get deformed in constrained areas before the two major sunspots. All this can be seen in a "somewhat" higher resolution on time lapses from professional telescopes, e.g., [3] (from the 1 m diameter Swedish Solar Telescope). [1] https://en.wikipedia.org/wiki/Sunspot https://en.wikipedia.org/wiki/Sunspot [2] https://en.wikipedia.org/wiki/Evershed_effect https://en.wikipedia.org/wiki/Evershed_effect [3] https://ttt.astro.su.se/isf/gallery/movies/2010/ https://ttt.astro.su.se/isf/gallery/movies/2010/

thulle 3y ago

Looks like melanoma.

nonrepeating 3y ago

One of my favorite facts about sunspots is, they’re still in extremely bright, they’re only dark due to contrast. An electric arc against a sunspot would look black by comparison (given typical logarithmic brightness measurement).

gattr 3y ago
You're right, here are some numbers: - photosphere temperature: 5870 K - sunspot umbra temperature: 3000-4500 K Per Stefan-Boltzmann law, this can make the photosphere up to (5870/3000)⁴ ≈ 15 times brighter.