Musings on optics, physics, astronomy, technology and life

A “talking light bulb” isn’t the product of some tin-hatted paranoiac — not if the light bulb in question is an LED model, and not if you’re using a Li-Fi signal in place of Wi-Fi.

What is Li-Fi, you may ask? Basically, it’s a type of optical wireless communications (OWC) in which a LED, not a radio-frequency router, gives off the signal that talks to your device. I wrote about it in this 2014 article for Optics & Photonics News. If you’d rather get your information by listening to it, researcher Harald Haas, who coined the term “Li-Fi,” gave a TED talk and demonstration about it in 2011.

Although that speech is four years old now, Li-Fi hasn’t made much of a dent in the marketplace … yet. Every wirelessly connected device you already own — smartphone, tablet, laptop, Fitbit, whatever — would need to have a second set of receivers and transmitters to communicate with Li-Fi as well as Wi-Fi “hot spots.” Still, it’s hard to imagine how the so-called “Internet of Things” will develop if we don’t increase the amount of electromagnetic bandwidth we use for communications — and Li-Fi would open up a lot of bandwidth for sure. Perhaps, in the not-so-distant future, flight attendants will hand out Li-Fi converters to airline passengers so that they can use their devices to communicate while traveling, the way they now hand out headphones (or used to hand out headphones, depending on your flight) and beverages.

Recently, Haas’ group, based out of the University of Edinburgh in Scotland, has figured out how to make organic solar cells into Li-Fi receivers as well as power sources. That’s cool, because in our quest to endlessly miniaturize our devices, we don’t leave a lot of real estate open for transmitters and receivers — or for additional battery packs, for that matter. If you’re truly interested in the technical details, you can find the original article here.

A slightly different, more marketing-oriented twist on Li-Fi technology is offered by a Boston-based company called ByteLight, which was recently acquired by another company called Acuity Brands. We shall see how that shakes out and how OWC will evolve over the next few years.

(P.S. Please, can we come up with a better phrase than “Internet of Things”? That sounds way too much like the “information superhighway” you might have heard about back in 1990 or thereabouts.)


Personal reminisces of Charles H. Townes’ long career are on the agenda of a special symposium that will take place at Frontiers in Optics/Laser Science 2015. Several of Townes’ past students from Columbia, MIT and Berkeley will share their memories, and other speakers will discuss his later-in-life contributions to astronomy and to projects such as the Townes Laser Institute at the University of Central Florida.

The organizer of the symposium is Elsa Garmire, who served as OSA’s second female president. If you are interested in her career, you can read about some of her early work in “A Short History of Laser Light Shows” — which is, perhaps, the only magazine article ever to mention both Charles Townes and Pete Townshend.

I can’t believe I let more than half the month of June go by without mentioning my article, “Optics in the Apollo Program,” in the June issue of OPN! I guess I was born without the gene for relentless marketing and self-promotion.

If you’ve been wondering how to read my article — because it’s not the featured “open access” article this months — then fear not: I have added it to my online clip file. Eventually I’m going to get around to uploading more of my work, but I thought it would be obviously better to start with the most recent work first.

If you’re ever at the National Air & Space Museum, you can see some of the Apollo-era optical equipment, or at least replicas of it. (Remember, the Apollo astronauts ditched quite a bit of gear on the lunar surface or just before re-entering Earth’s atmosphere.) Back in January I visited the main Air & Space Museum in Washington, D.C., and took a few photos.

Replica of Apollo 11 TV camera

Here’s a replica of the black-and-white television camera that Armstrong and Aldrin used to show us their Apollo 11 moonwalk.

Apollo spotmeter

The Apollo 11 astronauts used a spotmeter to judge the exposures for their film camera. Looks as if Minolta made this for NASA.

Apollo 7 camera

The Apollo 7 crew used this camera to make the first live telecast from space. This one’s the real McCoy.

Film magazine

Armstrong’s Hasselblad film magazine from Apollo 11. He had to bring this back because it contained all the unexposed film.

Command module camera

This camera flew in the Apollo 11 command module. And, yes, you can see the reflection of me and my digital camera.

Stereo camera

The stereo camera that Apollo 11 astronauts used to get closeups of rocks without bending over. This is probably a replica, because I don’t see any moon dust on it.


Replica of the Alignment Optical Telescope mentioned in the article. Apologies for the flash artifact.


Finally, a friend and I are reflected in a spacesuit’s visor.

The legacy continues

Last year at this time, I was working on an article for Optics & Photonics News about the late Stanford University professor Anthony “Tony” Siegman and his legacy of laser education. I’m pleased that the second installment of the international laser school named for him will take place this August.

The Siegman International School on Lasers began last year on the Stanford campus, where its namesake taught for many years. This year it is moving to Germany, to keep with its stated purpose of being a truly international school for young optical scientists. I’m sure it will be held in yet another country in 2016.

The 2015 school has lots of interesting programming lined up for its 102 accepted students. I wish all the attendees well and hope that the event results in many fruitful collaborations.

As I mentioned earlier this year, I was working on an OPN article about Charles H. Townes, one of the most important scientists of the 20th century, when he passed away. My article came out in the May issue of OPN, which is traditionally about lasers because of the annual CLEO conference. It made the cover of the magazine, so the editorial staff made it “open access” for everybody!

CLEO, by the way, is next week in San Jose, California. I wish I could attend, but it’s not in this year’s cards. The conference program sounds awesome — you can’t beat plenary lectures by two Nobel Prize winners. There’s no memorial symposium for Dr. Townes, as far as I can tell, but such things take time to organize; I’ll bet one will be held sometime in the next 12 months.

By now everybody has probably heard that today is the 25th anniversary of the launch of the Hubble Space Telescope. I couldn’t possibly put all the links to all the news coverage in this blog entry. We’ve got photos that show how HST changed the world, the breathtaking video made from the official 25th-anniversary Hubble photo, and the telescope’s amazing comeback story (with a mention of OSA to boot). The anniversary has its own website and you can even download a free ebook that will last as long as … well, as long as you have a device that can read and open the file and a storage medium that can save the file without corruption.

On and off, the Hubble Space Telescope has been a recurring theme of most of my adult life. I remember the initial anticipation, followed by the long wait in storage after the Challenger disaster (didn’t that storage cost $1 million per month, or something like that?). Somehow I don’t recall watching the launch, but I certainly knew it happened, and I certainly followed the headlines when the spherical aberration was discovered and the finger-pointing began. When I moved from Massachusetts to Maryland, I had to deal with a housemate who kept calling the orbiter “the Hubble Space Paperweight.”

But then I was at the AAS meeting in January 1994 when the “before” and “after” photos of a spiral galaxy (it might have been M101) were brought out to a hastily assembled brown-bag lunch crowd in one of the hotel ballrooms. When the “after” photo was revealed by someone lifting an opaque piece of paper over the second half of the viewgraph (remember viewgraphs, folks?), everyone broke into thunderous applause. Later, in the exhibit hall, I poured over an enlarged version of the photo mounted on a display board, and I marveled at the incredible detail.

Since then, of course, I’ve been as dazzled as anyone over the photos and the science that have come from Hubble. I’m proud to live a couple of miles down the road from one of the places that did so much work on the instrumentation. I did an article for Optics & Photonics News on the last Hubble repair mission, and I saw some of the last batch of instruments through the NASA Goddard clean-room window, and I even got to watch the astronauts go in there and handle some of the actual tools they would use during their spacewalks.

Recently I got a chance to attend a sneak preview of the National Geographic Channel’s documentary Hubble’s Cosmic Journey, narrated by Neil deGrasse Tyson (whose voice would thrill me if he were just reading the phone book…) — it looked fabulous on the big screen in the Nat Geo auditorium. I’ll leave you with a couple more links: reflections by one of the Hubble-repair astronauts and the Hubble 25th anniversary entry on the IYL blog.

Old cameras fascinate me. I still have my father’s old Argus C3, my mother’s Kodak Brownie Starmeter, and a couple of vintage Instamatics, among others. Somehow I acquired an Argus 75 box camera and a busted Falcon Miniature — there’s a hole in the latter’s body where the shutter button used to be, so that the interior will never be lightproof again. I’m not sure whether those two were purchased by Dad or another family member, but I ended up with them.

My interest in old cameras is certainly not limited to my personal stash. I totally geeked out when I was doing that OPN article on “Photography in the American Civil War” and got to spend an entire Saturday afternoon watching a guy making tintypes in Gettysburg, Pa. And I’ve written about the use of cameras and other optical equipment during the Apollo program in the late 1960s and early 1970s; it’s in the hands of the OPN editors now and will probably appear later this year.

So, imagine my delight at recent news reports that the widow of the first man to walk on the moon, Neil Armstrong, found a bag of his Apollo 11 memorabilia in the back of her closet — and, even better, lent them to the Smithsonian’s National Air & Space Museum. Best of all, the 16-mm Data Acquisition Camera that was supposed to have been left behind on the lunar surface came back to Earth!

I will have much more about this in my future OPN article, but basically, Apollo 11’s Eagle lander carried both video and film cameras. The video camera, mounted on the lander’s base, was pretty low-definition even by the standards of 1969 (that was the year the charge-coupled device was invented, but it certainly was nowhere near ready for prime-time broadcasting). The 16-mm motion picture camera was mounted so that it could look out the window of Eagle‘s ascent stage. It took much sharper pictures than the TV camera, but of course, no one could see those images until Columbia brought the film canisters (and astronauts) back home and technicians developed the film.

Many video clips of the Apollo 11 landing, such as this one, combine the film from the Data Acquisition Camera from the audio recorded by the Manned Spacecraft Center in Houston. What many people, especially those born after 1969, don’t realize is that the worldwide audience back on Earth could not see the film images in real time.

What the viewing public actually saw looked more like the CBS footage that you can find here and here: the live NASA audio combined with the voices of the television anchors, canned prepared animations, and the occasional “live shot” of people watching the coverage on giant screens. Because Armstrong had to steer around a boulder-strewn field at the last minute, there was a scary lag between the matter-of-fact animation’s depiction of the touchdown and the actual moment of contact with the lunar soil.

I can hardly wait until Armstrong’s stash goes on display at the Smithsonian. It will be awesome to see the actual camera that took some of the most exciting motion-picture footage of my lifetime, even if it wasn’t broadcast in real time.

(NASA’s own inventory of the objects appears here.)

Before I sign off, I’d like to mention a few other science-related stories that I’ve recently found interesting. I think I’ve mentioned most of them on Facebook, either on my personal or my professional page.

  • First, a Pittsburgh startup company has gotten FDA approval for a new kind of internal tissue adhesive. I know someone whose husband could have really used this stuff after the abdominal surgeries he’s had over the past couple of years. The scientist who developed the adhesive is married to one of my high school classmates.
  • A handheld Raman spectroscopy probe could help neurosurgeons find sneaky, aggressive cancer cells within brain tissue. This too is rather near and dear to me at the moment, because a close friend of a close friend is in hospice care for glioblastoma, which is pretty much the worst kind of brain cancer you can get. She just turned 46 years old, which is way too young to die.
  • Finally, in March and September, you’ll have a couple of opportunities to help measure the brightness of the night sky where you live. You should have no trouble remembering the March date on which this citizen-science effort begins, because it falls on Super Π Day.

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