Onward and Backward

by wjw on February 5, 2021

Back in the days of my youth, optical astronomy was done with telescopes, and the sky recorded on dry glass plates.  Starting in the 1890s, millions of glass plates were viewed, then stored in archives throughout the world.  They’ve been largely ignored in the years since— there are so many, where do you start?  Yet it’s a scientific archive filled with undiscovered treasures.

But lately a team from the University of Chicago and and the Kavali Institute has been scanning and digitizing the old plates, using off-the-shelf equipment, and finding a few things the original viewers missed.

“After we select a plate, we make sure the surface is clean so that dust particles don’t get mistaken for stars in the final image. Then, we set our scanner to the highest quality we can and produce an image file. In effect, we are considering the scanner to be a scientific instrument: for each small piece of information on the plate, we get a digital rendition of the amount of light transmitted through the photograph. From there, we upload the resulting file to a website which maps the celestial coordinates onto the image, which also creates a file in a standardized format for astronomical analysis.”  

. . . “The simplicity of the process makes it possible to digitize a large number of plates in a relatively small amount of time.  It also has the benefit of not requiring a custom scanner, making it accessible to teams without the wherewithal to design or purchase one. Custom scanners are prohibitively expensive. If our methods can be generalized, then photographic plate collections from multiple observatories could be rendered available for use in scientific research.”

One of the first plates scanned turned up a possible supernova occurring in 1903 in the constellation Pegasus.

When astronomers noticed an anomalous dimming seen in Tabby’s Star KIC 8462852, they looked at old glass plates of the same region to show that the strange star is actually fading over longer time scales. Another study looked at the nearby white dwarf named Van Maanen’s Star and demonstrated that astronomers had potentially documented evidence for exoplanets waaaay back in 1917… had they known to look for it.

Forward in science . . . by revisiting the past!  Onward and backward!

[via Janice Gelb]

Derek February 5, 2021 at 2:30 am

Very interesting, Walter. I occasionally volunteer at the Lick Observatory, where I believe a similar project is underway. One of the resident astronomers there once showed me a photographic plate from 1957 which had a streak–apparently the earliest instance of an artificial satellite ruining an exposure!
If you ever visit the area post-plague, a summer concert and an evening with the telescopes at Lick is a great experience (do let me know if you’ll be in the vicinity!)

You’re probably aware of the field of archaeoastronomy–similar in spirit, but typically with far less concrete data to work with. (Wikipedia has a less than coherent overview; I learned a lot from the book “Exploring ancient skies”.)

Speaking of topics cosmological, was “Tecmessa” loosely inspired by Kalifriki’s “thread”?

John Appel February 5, 2021 at 11:02 am

That’s fantastic news and a great approach. I’m always impressed when new techniques are applied to study artifacts which we thought we knew everything about, and new discoveries are made.

wjw February 6, 2021 at 2:34 am

Derek, I think I’m reasonably certain that Tecmessa wasn’t inspired by Kalifriki’s thread, which I had forgotten about till you mentioned it. (Always wanted more Kalifriki stories, sigh.)

I had also forgotten that there was a sword named Tecmessa in CJ Cherryh’s Gate of Ivrel. (The name means “She Who Judges.”) If I’d remembered, I’d have given the sword another name.

Derek February 6, 2021 at 2:40 pm

Walter, the ‘She who judges” translation is very interesting.
I’d assumed it was an allusion to Tekmessa, wife/slave/war booty of Ajax via Sophocles and/or the asteroid bearing that name.
I wonder if the meaning predates the character? I’m not versed enough to say if Tekmessa’s actions could have inspired the meaning, as with Quisling.

Reminiscent of Gene Wolfe’s Terminus Est after a fashion.

I wasn’t fortunate enough to meet Roger, which will be a lifelong regret. I would’ve been just a callow teen in his lifetime, one who had found a copy of “The hand of Oberon” in a library. I’d never read anything like it, and found Roger’s universe mesmerizing enough that when I found his oeuvre at the MIT science fiction library years later, it was like “Manna from heaven”.

I viewed this recording of a reading by Roger from 1986 a while ago:
If you haven’t seen it before, I hope it inspires some pleasant memories of your friendship.

wjw February 7, 2021 at 5:27 pm

I’m reasonably certain that the name “Tecmessa” predates the mention of the character in the Sophocles play. There was also an Amazon Tecmessa who was killed by Herakles, presumably in an even earlier reference.

John Appel February 7, 2021 at 6:17 pm

On a somewhat related note, I was reading a book about Greene & Greene furniture, which was built in the early 20th century for a number of wealthy houses the Greene brothers were erecting. Since all the pieces were made for specific clients and each is one-of-a-kind (or part of a one-of-a-kind set), researchers and craftspeople have been trying to figure out just how the joinery worked, because looking from the outside it didn’t seem to make sense. But now some pieces have been X-rayed to reveal screws and blind through-tenons and such.

Reading *that* reminded me of the finds in recent years of paintings under paintings, or murals, revealed by using x-rays on walls and pieces of art work. It’s not quite the same as just looking at old plates and digitizing them, but strikes me as a close relative, conceptually.

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