BAN #253: HDR eclipse, Snow in Autumn

14 September 2020   Issue #253

[Spiral Galaxy M81 image credit: Adam Block/Mount Lemmon SkyCenter/University of Arizona]

Subscribers are a refreshing bit of weather during any season.

Pic o’ the Letter

A cool or lovely or mind-bending astronomical image/video with a short description so you can grok it

Did you see the total solar eclipse of 2017? I was in Wyoming with my wife and a couple of dozen science enthusiasts for the event, and it was my first time seeing totality. My thoughts are in that link; but it was one of the most amazing things I have ever seen in my life. The solar corona was so obvious, reaching out from the Sun like the tendrils of a sea jelly. It was arresting.

There was science to be had in a total eclipse, as well as beauty… simultaneously. For the 2019 eclipse, an article recently posted to the Research Notes of the American Astronomical Society talks about how combining images from the ground and from space provides insight into coronal structural, and how features can be traced from the solar surface to far above it.

In it they talk about how co-author Nicolas Lefaudeux created high-dynamic-range photos (that is, able to show both very faint and very bright features at the same time), and display a small section of the photo. I found Lefaudeux’s site, where he has a much larger version of it. With his permission, I show it to you here:

[An HDR composite of the July 2019 total solar eclipse taken from Cerro Tololo in Chile. Credit: Nicolas Lefaudeux]

Ye. GADS. And, I might add, the tallest image I think I’ve posted here.

It took a lot of effort to get the photos he used to create this mosaic, let alone process them. It’s not possible to get a single shot like this. The Moon is very dark, lit only by reflected Earthlight  — literally, sunlight hitting the Earth, reflected to the Moon, then reflected back to us. The full Earth from the Moon is much brighter then the full Moon seen from Earth, but still that’s not much compared to the inner corona.

The RNAAS paper notes this mosaic isn’t “photometrically correct”; that is, some brightness features are enhanced while others suppressed. But it is jaw-droppingly beautiful, and does have scientific use in tracing features over large distances.

Astronomy is pretty cool that way. A lot of the images we see are more art than science, but there is always some of both.

… which reminds me, I need to start thinking about the 2024 total eclipse.

Blog Jam

What I’ve recently written on the blog, ICYMI

[Gravitationally lensed image of a normal galaxy… 12.4 billion light years away. From Monday’s article. Credit:  ALMA (ESO/NAOJ/NRAO), Rizzo et al.]

Monday 7 September, 2020: Why is there a normal galaxy sitting at the edge of the Universe?

Tuesday 8 September, 2020: A triple-star gravitational dance creates ridiculously complex sculptures

Wednesday 9 September, 2020: The Moon is getting a little rusty. Like, *actually* rusty.

Thursday 10 September, 2020: Not aliens but ORCs: What are these mysterious giant radio rings in the sky?

Friday 11 September, 2020: What’s the matter with dark matter? Observations show we’re missing something

I recommend

Something I think you’ll like

As you may have heard, we had quite the weather in Colorado this past week; it went from broiling hot to freezing nearly overnight (plus, my area was under a gigantic smoke plume from the Cameron Peak wildfire). Despite the rainy mix, I had to go out and run some errands, and when I flipped on the local classical station they were playing an amazingly gorgeous piece, lush and emotional.

The name? “Snow Falling in Autumn”. How perfect! And chosen on purpose, obviously. It’s by Chris Pilsner, a local Colorado composer. I found it on YouTube, and the video is really lovely. The first minute explains why:

Wow. And what an experience for those young musicians!

It’s extremely rare for me to hear a piece of music that I love that I’ve never heard before; in general a lifetime of listening to classical music means you’ve pretty much covered all the romantic composers (the last one was over a decade ago, when I stumbled on Jack Gallagher’s stunningly lovely “Berceuse”). But there are still people out there writing new classical pieces, and they can be surpassingly lovely. I’m glad I turned on the radio when I did.

Et alia

You can email me at (though replies can take a while), and all my social media outlets are gathered together at Also, if you don’t already, please subscribe to this newsletter! And feel free to tell a friend or nine, too. Thanks!