Weighing Planets

At this month’s meeting of the American Astronomical Society, the team developing the NEID spectrograph at Kitt Peak National Observatory announced the instrument’s first light and released a great, processed image of the first spectrum that illustrates much of what I’ve talked about when giving behind-scenes-glimpses of the work. This is a spectrum of 51 Pegasi, which happens to have been the first star discovered to have an exoplanet back in 1995.

Credit: Guðmundur Kári Stefánsson/Princeton University/Penn State/NSF’s National Optical-Infrared Astronomy Research Laboratory/KPNO/AURA

The rainbow in the image above shows light from the star 51 Pegasi spread out by the spectrograph. To the left, you see the spectrum magnified so you can see more details. In particular, you see dark lines bisecting the rainbow in different places. These lines are caused when elements in the star’s atmosphere absorbs a little bit of the light. The dots above the lines come from a “calibration” image. They serve as a road map to tell you where you are in the spectrum. When a planet pulls the star toward us, those dark lines move a little bit toward the blue end of the spectrum (to the left in the image above). When the planet goes behind the star, those lines move a little toward the red end of the spectrum (to the right, in the image above).

What’s cool about this kind of measurement is that how far the planet moves those lines is directly related to how massive the planet is. If you measure the line movement precisely, you can measure how much the planet weighs. If you then use another telescope and take images of the star and watch for the planet to cross in front of the star, you can measure how much the planet makes the star’s light decrease. That tells you the diameter of the planet. With the diameter and the mass, you can calculate the density, which tells you whether you’re looking at a gas giant, a rocky world, a water world, or an ice giant world.

What’s more, I was on-hand when that first image was taken. We celebrated by pulling out a bottle of sparkling cider and toasting the instrument’s success. Afterwards, we got back to work characterizing and testing the instrument’s behavior. As you can tell from the image below, we have lots of people in the control room on these commissioning nights!

This past week has been especially fun as a science fiction writer and long time fan. We’ve been starting our nights by observing the star Tau Ceti, which appears in many science fiction novels, movies, and TV series. Among the notable novels where Tau Ceti appears are such classics as Isaac Asimov’s The Caves of Steel, Robert A. Heinlein’s Time for the Stars, and Samuel R. Delaney’s Empire Star. In Star Trek, Tau Ceti is known as the home of the doomed cargo ship, Kobayashi Maru. The system is the home of the planet Sea of the Morningstar in Bodacious Space Pirates, a wonderful anime series.

In fact, the star itself is very similar to the sun. It has a similar spectral type and a mass about 0.78 times the mass of the sun. It has four candidate planets in orbit and it’s a little less than 12 light years away, so it seems conceivable these are planet humans could eventually visit. I even gave it a cameo in the new, upcoming edition of my novel, The Pirates of Sufiro.

New Year's Eve at Kitt Peak

Earlier this week, I rang in the new year while on the job, helping observers commission the DESI spectrograph on the Mayall 4-meter Telescope at Kitt Peak National Observatory. Looking back, I see I rang in eight years of the last decade at the observatory. So, working on New Year’s Eve is getting to be something of a tradition for me.

Working at the observatory on New Year’s Eve is much like working on any other night of the year. It all starts out with me evaluating the weather. In the photo, I’m standing in front of the Mayall, watching the sunset. Throughout the week I had watched a forecasted storm for the night get downgraded to the point that we expected reasonable observing conditions. The night actually arrived with dark clouds and light snow. Not only was this unwelcome for observing, but New Year’s Eve was the last night of my shift and I didn’t relish the idea of driving on snowy roads.

The poor weather didn’t keep us from our commissioning work. On an instrument where 5000-robotic fibers must be precisely aligned with targets on the sky and then send the light from those targets to ten spectrographs, there’s still plenty of work that may be accomplished with the dome closed. We started with some spectrograph calibration tests, trying to answer whether it matters where the telescope is pointed when we calibrate the instrument. There was some concern about whether or not twisting of fibers at different telescope orientations might make subtle changes to the light going through them and affect the measurements we hope to make. This is important to understand and characterize before we start making measurements.

Another job we had was to test a camera that looks at the fibers on the telescope. That’s how we know the fibers are on the correct objects. We can test this camera because DESI includes some fibers that can be illuminated. This means the fiber view camera can see the position of some fibers even when we’re not looking at the sky. The telescope itself is big and flexes as it points around the sky. Understanding how objects appear on the fiber view camera depending on where we point is also an important job. We can do a lot by pointing the telescope in the closed dome with the test fibers illuminated.

Testing a new, complex system also uncovers software bugs and errors in procedure. The lead software developer on this project is fond of using barnyard sounds like a chicken clucking or a cow mooing when an error occurs. So, these sounds do occasionally intrude into our work, which means the software people need to debug code or help observers refine procedures. This is also productive work for a cloudy, snowy night. I’m also convinced that I need to find a way to work barnyard noises into some future high-tech science fiction space opera!

At 10pm, we tuned into the live feed from Times Square in New York to watch the ball drop while we worked. At midnight, we took enough of a break to toast the new year with mugs of coffee. Kitt Peak National Observatory is on the land of the Tohono O’Odham, so no alcohol is allowed, even if we weren’t working.

When the decade started, I thought of myself as “the temp” on the operations staff at Kitt Peak. I returned to Kitt Peak after nearly fifteen years to help the observatory with a staffing challenge and stabilize my income long enough to achieve some personal goals. Ten years later, I’ve achieved most of my goals, but I still think of myself as “the temp.” It’s an attitude that serves me well.

In the current political climate, I can’t guarantee my job will always be funded so I don’t take for granted I’ll have this job for an indefinite period of time. More importantly having the attitude of being “the temp” assures that I always feel free to speak my mind when needed and avoid self censorship, which is important in a job where I’m responsible for the safety of visitors. Also like any good temporary employee, I want to stay in the good graces of my employers, so it assures that I always try to do my best and constantly hone my craft.

As one decade finishes and another begins, I’m thankful to have a good and interesting job expanding humankind’s knowledge of the universe, but I also stand ready to take on whatever challenges that universe decides to throw at me in the coming decade.

A Stormy Holiday

This year, I spent Thanksgiving on the job at Kitt Peak National Observatory. Because my daughter had the week off, we opted to have our family celebration at home on Monday before my work week began. Over the last dozen years, I’ve spent several Thanksgivings on the job. It’s not necessarily a bad way to spend the holiday. My co-workers and I get to share a turkey dinner on Thanksgiving.

Of course we have diverse political views, so sometimes we find ourselves skirting those topics just like many families around the country. In many ways, those of us who work at the observatory are like a family, bound by a common passion for exploring and understanding the universe around us. Moving that mission forward is one of the things that makes working at the observatory on a holiday worthwhile.

Then again, working at a ground-based observatory, we’re subject to the wiles of the weather and this holiday weekend has proven to be a stormy one. Times like this do give us awesome sunsets like the one above, but not much time looking at the stars. We had rain, fog, and wind gusting upwards of 70 miles per hour. These are not conditions one should subject precision scientific instrumentation to. So, why do I have to hang around on nights like this?

First and foremost, there’s the chance the weather may improve enough for us to open. In fact, on my first two nights of this shift, even though the weather looked hopelessly bad, we did manage to get about two hours of data each night when the weather calmed and dried out briefly. Another reason I have to be available is that some of the instrumentation will be damaged if we lose power. On a remote mountaintop in the Arizona desert with 70 mile per hour winds and rain and snow, that’s a real possibility. If power goes out and doesn’t come back before battery backups drain, I may have to jump into action to start an emergency generator. What’s more, we have had circumstances where the weather has damaged buildings and I may need to take action to protect the telescopes or instrumentation.

Fortunately, our buildings and power systems are designed well enough, I don’t have to spend my entire night actually saving the telescope. So, while I’m waiting to see if my services are needed, I get a chance to do some proofreading. This weekend, I’m proofreading the novel Upstart Mystique by Don Braden, which my company Hadrosaur Productions will be publishing in early 2020. It’s a great science fiction novel about a group of colonists who are pulled off course and are forced to land on a planet they didn’t intend to settle before their ship is destroyed. The novel explores fascinating questions about human and machine intelligence.

I became a writer because I love to read. Hadrosaur Productions exists, in part, as a way to give back. The company allows me to seek out writers whose voices deserve to be heard and bring their books to readers. I know many people who read this blog are fans of my writing, but I encourage you to check out the works of the other people I publish as well. This holiday season, I’m especially thankful for writers like Greg Ballan, Joy V. Smith, and David B. Riley who have given me the privilege of editing their stories and I’m thankful to all the readers who are eager to find new, exciting fiction. As we enter this holiday season, please take a look at http://www.hadrosaur.com. I bet you’ll find a good book to share with the adventuresome readers in your life.

Stars, Galaxies, and Fiber Optics

The first time I remember learning about fiber optics was in a behind-the-scenes article published in 1980 or so about the making of Star Trek: The Motion Picture. The article talked about how they got light to all the buttons on the bridge set and showed them illuminated with bundles of optical fiber. Nowadays, as I’ve mentioned in several earlier posts, I work with instruments that use optical fiber to carry light collected by each of the telescopes I work with to the instrumentation where its analyzed.

On the telescope side, those fibers are attached to an optical assembly that must be placed at just the right spot to catch focused light. If the star or galaxy is out of focus, not all the light goes down the optical fiber. We also have guider cameras that work to keep the object precisely aligned on the fiber so all the light gets to the spectrograph. It’s a lot of complex hardware to work right to precisely measure the the redshift of distant galaxies or look at a star and determine whether or not it has planets in orbit. This past week, we’ve been commissioning both the DESI spectrograph at the Mayall 4-meter and the NEID spectrograph at the WIYN 3.5-meter. One of the most important milestones is to get light from the object you want to measure to the spectrograph and see if you get the flux you expect. Here’s the NEID team at WIYN looking at early test results.

Yes, light leaves a star dozens of light years away, enters our telescope, goes down the optical fiber and is photographed with the spectroscope, then all that data can be viewed and analyzed on a laptop computer. When I filmed the trailer for The Astronomer’s Crypt a couple of years ago, I was asked why we didn’t use a room full of fancy computers and monitors. We just had a couple of computers, one of which was a laptop. The reason is that I’ve seen a lot of control rooms where simple computers are the only ones present!

As you can imagine, it’s quite a relief to see all the work pay off in a spectrum that shows the flux level you expect. All of this is pretty exciting stuff and, as it turns out, my birthday fell during this past week’s tests. Seeing NEID as it nears readiness for scientific use is pretty exciting in its own right, but we had another surprise on the day of my birthday. Ethan Peck, who plays Spock on Star Trek Discovery, was on a road trip and decided to visit the observatory. A tour was arranged and he spent the beginning of the night at the WIYN telescope. For me, it was quite a thrill to have Spock, of all people, wish me a happy birthday! He brought a Polaroid camera with him and we snapped a photo of us standing by my control station. Here we are at WIYN. Ethan Peck is in the center (in white) and I’m to the left.

Meanwhile, across the mountain at the Mayall 4-meter, commissioning has continued on the DESI instrument. The instrument had its official “first light” a couple of weeks ago and a wonderful image was released that, I think, really illustrates the power of DESI.

Image credit: DESI Collaboration, Legacy Surveys; NSF’s National Optical-Infrared Astronomy Research Laboratory/NSF/AURA

Here you see an image of all 5000 DESI fibers superimposed on the sky. At the bottom of the fiber array is M33, the Triangulum Galaxy. Below that is a view of the spectrum from just one of the 5000 fibers showing the light from that little piece of the galaxy. In it, you can see the lines labeled that denote the presence of hydrogen, oxygen, nitrogen, and even sulfur. Now remember that each fiber in that picture gives the same kind of data for the piece of sky its on. You can read the full press release about DESI’s first light at: https://nationalastro.org/news/desis-5000-eyes-open-as-kitt-peak-telescope-prepares-to-map-space-and-time/

All of the robotic positioners moving those fibers at the top of the Mayall telescope get hot and there’s a chiller system to keep them cool. This week, that chiller system will be automated, but last week, we had to monitor it by eye and it requires a person to turn the system on and off by hand. The person doing that remarked how spooky it is to be in the depths of the Mayall with all the lights out and remarked how she kept looking over her shoulder, wondering if someone was there. This is another aspect of my job that definitely helped to inspire The Astronomer’s Crypt. You can learn more about the novel and see the trailer I mentioned earlier at http://www.davidleesummers/Astronomers-Crypt.html.

Making Instruments Work

Today, I’m at the TusCon Science Fiction Convention in Tucson, Arizona. You can get all the details about the event at http://tusconscificon.com. One of the topics I’ll be speaking about is the work we’ve been doing for the last year, installing the DESI Spectrograph on the Mayall 4-meter telescope. At this point, installation is nearing completion and we’re beginning the process of commissioning the instrument. In short, we’re actually making it work with the telescope so we can get the data we hope to obtain.

DESI isn’t the only instrument that we’ve recently installed. We’ve also installed the NEID spectrograph on the WIYN telescope. While DESI has the goal of making a 3D map of about one-third of the sky, NEID has the goal of looking for planets around other stars. I’ve shared quite a bit about the DESI installation because that instrument is of a scale that it required a major refit of the telescope. The NEID spectrograph has involved a similar amount of time in development, but much of that development has happened off site at places such as Penn State University and the University of Wisconsin. NEID, which rhymes with fluid, takes its name from the Tohono O’Odham word meaning “to see.”

Two weeks ago, the port adapter, built by the University of Wisconsin, and the spectrograph, built at Penn State University, both arrived at WIYN and have been installed at the telescope. You can see the port adapter on the side of the telescope in the photo above. It’s job is to capture light coming through the telescope from a distant star and feed it into fiber optics that run downstairs to a high precision spectrograph.

The spectrograph itself lives in a clean room on the WIYN Observatory’s ground floor. To get the kind of precision needed to see planets around other stars, the temperature within the spectrograph must be carefully maintained and the spectrograph elements must be kept in the same relative position. Footsteps nearby could disturb this device. Because of that, the spectrograph itself is built inside a coffin-like housing. Once the Penn State team gets everything set up, they’ll seal up the coffin and, unless there’s a serious problem, no one will look inside again. I got to peak inside the spectrograph a few days ago and it may be my only view.

Now that the instrument is installed at the telescope, we have to make sure everything works as it should and programmers are working to make sure we have software to assure we can efficiently get the data we need. We’re starting with the port adapter itself. I point the telescope at stars and a team of scientists and engineers check the function of the various parts within the adapter to make sure they understand the alignments on the sky, which are necessary for tracking the stars. They check the tip-tilt electronics, which make sure we get as much of the star’s light as possible down the fiber, and make sure all the calibration functions work. After this, work will begin commissioning the spectrograph itself. This is a process which takes a few months to complete to assure we’re getting the performance out of this instrument that we want.

Commissioning nights are very different from normal observing nights at a telescope. On a normal observing night, it’s often me and an observer. Often the observer isn’t even at the telescope, but working from their home institution, controlling a camera on the telescope over the internet and talking to me through computer chat. On a commissioning night, I can have anywhere from five to fifteen people in the control room with me, all working on different elements of the instrument. This marks a busy and exciting time as we get these new instruments ready for service at Kitt Peak National Observatory.

TusCon 46

Next weekend, I’m delighted to return to TusCon in Tucson, Arizona as a panelist and book dealer. This year, TusCon’s author guest of honor is Jonathan Mayberry. The artist guest of honor is the very talented Chaz Kemp, whose work I’m proud to display in my home. The toastmaster is Weston Ochse. The convention will be held at the Sheraton Tucson Hotel and Suites at 5151 Grant Road. You can get all the details by visiting http://tusconscificon.com.

My schedule at the convention is as follows:

Friday, November 8

Changing Channels: How/Why Do Authors Change Genre? Panel Room 1. 6:00 pm – 7:00 pm. Given how much publishers want writers to stay in their box why deal with the arguments? Are the publishers right? Will your fans follow? Are you just changing things up for fun? On the panel with me are Frankie Robertson, Jill Knowles, Paul Clinco and Thomas Watson

Meet the Guests. Ballroom. 7:00 pm – 9:00 pm. Hobnob and schmooze with our guests, enjoy the cash bar, and laugh it up with Toastmaster Weston Ochse.

Saturday, November 9

What I Know Now, What I Wish I Knew Then: A Writer’s Journey. Panel Room 1. 9:00 am – 10:00 am. Successful writers talk about what they`ve learned along the way. On the panel with me are Eric T. Knight, Gloria McMillan, Ross Lampert

Autograph Session. Autograph Area. 3:00 pm – 4:00 pm. Come get autographs from your favorite folks. Some are even probably selling stuff. Not only can you get my autograph, you can get autographs from Ross Lampert, Tabitha Bradley, and Thomas Watson as well!

Surveying the Universe – Our Five-Year Mission to Create a 3D Map of the Universe. Panel Room 2. 5:00 pm – 6:00 pm. Did you know Kitt Peak was mapping the universe? Come to this presentation to find out about awesome stuff in Tucson’s own backyard.

Sunday, November 10

Southwest Folklore, Urban Legends, and Paranormal Encounters. Panel Room 1. 10:00 am – 11:00 am. A lot of cultures meet here. With a lot of history. How have these combined to build our legends and ghosts? On the panel with me are Chris R. Chavez, Liz Danforth, and Weston Ochse.

Making Light of the Dark: Humor in Horror. Ballroom. 2:00 pm – 3:00 pm. Terror seems like it should preclude amusement. What makes us laugh does not seem like it should be capable of also making us scream. But while seemingly attempting to achieve opposite results, comedy and horror are intricately linked. While playing on different emotions, both are devised to generate specific and extreme reactions from their audiences. Two sides of the same coin, humor and horror are strong on their own, but working together, they can create a marriage of unexpected twists and turns. This panel will explore the rise of the horror comedy and address why the combination works and why it sometimes fails. On the panel with me are James Sabata, William Herr, Wolf Forrest, and K.S. Merbeth.

When I’m not at one of these events, I’ll be at the Hadrosaur Productions table in the dealer’s room. Please come by and shop our fantastic selection of books and I’ll be happy to talk to you more about any of the panel topics, or things that don’t even relate to the panels. Also, be sure to ask about the annual party that we thrown in conjunction with Massoglia Books at TusCon. It’s always a great event and I hear there will be cake.

Stars Wobbling at the Speed of a Desert Tortoise

In recent posts about new observing projects at Kitt Peak National Observatory, I’ve largely focused on the DESI spectrograph which aims to create a three-dimensional map of the northern sky. In fact, I’m in Denver, Colorado this weekend at MileHiCon and I’ll be giving a presentation on this very subject. However, this isn’t the only new instrument I’m helping to deploy and commission.

At the WIYN 3.5-meter we’re installing a spectrograph called NEID. Kitt Peak sits on the land of the Tohono O’Odham people in Southern Arizona. The acronym is derived from the Tohono O’Odham word meaning “to see.” The actual acronym is: NN-EXPLORE Exoplanet Investigations with Doppler Spectroscopy. In other words, it’s an instrument that will be used to look for planets around other stars. Like the DESI spectrograph, fiber optics are mounted to the telescope and feed a spectrograph two floors below the telescope. Just over a week ago, I helped to run the fibers from the point the instrument will be mounted down to the spectrograph room. In the photo, you can see the fiber optic cable laid out like undulating waves at the base of the telescope. The instrument itself will be mounted at the round port that currently has the white, rectangular sign.

The way a spectrograph like NEID finds planets around other stars is by measuring how much they move toward and away from the Earth when they’re pulled by orbiting planets. You likely see spectra all the time. A rainbow is a spectrum of the sun. In a spectrum are characteristic lines caused by elements in the star’s atmosphere. When a planet tugs the star toward Earth, those lines move toward the blue end of the spectrum. When a planet tugs the star away, the lines move toward the red end. Of course, one of the hopes of exoplanet science is to detect Earth-like planets around other stars, or more specifically, Earth-sized planets in the zone around a star where water can be liquid. If you imagine watching our sun from another star, we’d see the Earth pull the sun toward or away from us at about 30 centimeters per second, or about the speed of a desert tortoise!

To see this small motion, you need to be able to see the spectra—the rainbow—at very high resolution. This is more than magnification. You need to see it at great detail. A spectrograph that can do that is often fairly big and it’s very difficult to mount it to the side of a moving telescope. This is why we use a fiber to capture the light and send it to a spectrograph in a different room. This allows the engineers to build the spectrograph as big as they need, but only requires them to mount the fiber to capture the light to the telescope.

Fiber optic cable is meant to be tough, but it can break, so it’s gratifying after we make the run to be able to shine light through the cable and see it at the other end, as we see in this post’s second photo!

Besides looking very specifically for Earth-like planets, the NEID spectrograph will be providing support for NASA’s Transiting Exoplanet Survey Satellite, or TESS, mission, which is searching for exoplanets around the closest stars to Earth. Once TESS discovers a planet, we can observe it with NEID and get more precise mass and density information about the planet. Such measurements help us better understand the composition and formation of the planets around other stars. It’s a very exciting time at Kitt Peak as we deploy these spectrographs which will help us understand both planets in our galactic neighborhood and the overall structure of the universe.