Starship Asterisk*

Perihelion Sun 2023

Explanation: Perihelion for 2023, Earth's closest approach to the Sun, was on January 4 at 16:17 UTC. That was less than 24 hours after this sharp image of the Sun's disk was recorded with telescope and H-alpha filter from Sidney, Australia, planet Earth. An H-alpha filter transmits a characteristic red light from hydrogen atoms. In views of the Sun it emphasizes the Sun's chromosphere, a region just above the solar photosphere or normally visible solar surface. In this H-alpha image of the increasingly active Sun planet-sized sunspot regions are dominated by bright splotches called plages. Dark filaments of plasma snaking across the solar disk transition to bright prominences when seen above the solar limb.

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Really very nice.

But where is "Sidney"???? (Yes, even NASA make typos)

A pity it's monochrome

“Sidney”.
What else would one expect when the “Opening for APOD Supported Graduate Student” position states that “…interested perspective students are requested to email me [RJN]…”

The sun is nice; but don't look at it; it's very bright! Don't touch it!
It is very hot!

pjw wrote: ↑Sat Jan 14, 2023 11:31 am But where is "Sidney"???? :D (Yes, even NASA make typos)

Out looking for Waldo, of course!

pjw wrote: ↑Sat Jan 14, 2023 11:31 am But where is "Sidney"???? (Yes, even NASA make typos)

I live in SIDNEY (with an I ) on Vancouver Island on the west coast of Canada. We also have an astronomical telescope nearby but it is not the one mentioned here so it really was an APOD typo. https://en.wikipedia.org/wiki/Dominion_ ... bservatory.

I'm curious about the one filament near the center of the image,
which looks like an integral symbol.

It seems so smooth in both the curvature and thickness.
I guess it, too, is a prominence forming over a sunspot.
I wonder if they tend to begin like this and then get lumpier and
misshapen over time as they develop?

pjw wrote: ↑Sat Jan 14, 2023 11:31 am But where is "Sidney"???? (Yes, even NASA make typos)

Thanks! Fixed it (to Sydney).