Time lapse of this week's large sunspot | Hacker News Reader

Time lapse of this week's large sunspot

astrobin.com

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

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-an...

Nicely done! Any idea what the field of view is?

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.

That’s wild!

What are the features apart from the granules? The black feathers rimming the totally dark areas? What are these up close?

Wikipedia has it has a pretty great article on sunspots.

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.

Nice. Now this is quality content. GJ

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 ;-)

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".

>..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.

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

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.

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?

(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

[2] https://en.wikipedia.org/wiki/Evershed_effect

[3] https://ttt.astro.su.se/isf/gallery/movies/2010/

Astrobin is an amazing resource. Like Flickr for astronomers

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.

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

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

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).

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.

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

Looks like melanoma.

is this bad or good

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