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.

DESI Naked!

This weekend finds me at Bubonicon 51 in Albuquerque, New Mexico. I’m moderating panels about space cowboys and large scale scientific surveys. If you’re in town, click the link to get the details and drop by. I’d love to see you there. Of course, part of my interest in large scale scientific surveys has to do with the work I’ve been helping with over the last year and a half, installing the DESI Spectrograph at the Mayall 4-meter telescope at Kitt Peak National Observatory. During my my recent shift at the observatory, I got a rare look at the new instrument not just “under the hood” but before the hood even went on.

In the photo above, you see DESI on the left, just over the orange platform. Standing on the ground floor in the foreground are just a few of the telescope engineers and technicians who have been installing this new, innovative instrument which will be used to make a 3D map of about a third of the known universe. DESI itself is an array of 5000 fibers mounted on robot positioners that can be precisely centered on targets each time the telescope moves. The light from those objects then travels down fibers two stories below. The fiber bundles are ready to be run along the telescope. You see them coiled up on the white carts to the lower right of the photo above. Each black cable contains 500 fibers. One of my jobs this week was labeling those cables so people can keep it straight which cable is which as they run them along the telescope.

Here are all the DESI fiber positioners mounted to the telescope. You can see each of the ten cables coming up into ten sets of fiber positioner “petals.” Each of these petals was installed into the telescope with great care about a month ago. Light was placed on all the fibers and it was confirmed that in all the transportation and installation, none of the fibers were broken. All of them transmit light as expected! This week, the control electronics are being wired up and routed through the telescope. Once this chore is complete, more testing will happen to assure that the fibers still transmit light and each of the robot positioners moves as expected using the electronics routed through the telescope.

All of those fibers will eventually come into a clean room downstairs to a series of ten spectrographs. Do you begin to sense a pattern? Ten petals, ten cables, ten spectrographs. As it turns out, another job of mine this week was helping to install the seventh spectrograph, which you see in the lower right of the photo above. Western fan that I am, I feel like you can now cue Elmer Bernstein’s score for The Magnificent Seven. Of course, that won’t last long. soon we’ll have an eighth, ninth, and tenth spectrograph.

Each of those spectrographs will be used to examine the light from 500 fibers. To make the map, we’ll be using these spectrographs to see how far characteristic chemical lines in spectra have shifted from where they normally sit within the rainbow toward the red end, which is one measure of how far away those objects are. We’ll compare that to statistics of how far apart they are, which turns out to be another measure of how far away they are. That said, just because we’re mostly looking for the redshifts, there will be all kinds of other spectral data available that can tell astronomers all kinds of information about properties of galaxies all over the sky. One of the most exciting things about the DESI program is that this data will be available to all. In this post, I may be laying DESI bare for all to see, but the whole project will be laying much of the universe bare, and in the process expanding the body of astronomical knowledge.

  • For a fictional and frightening look behind the scenes at an astronomical observatory, read The Astronomer’s Crypt.
  • To take a tour through the wonders of the solar system, read The Solar Sea.
  • To travel back in time to the Old West, check out Owl Dance!

The Pointing Dance

This week, I have been engaged in an important, albeit tedious activity at the WIYN 3.5-meter telescope. I have been building pointing maps. Telescopes are large, bulky machines that have to point with extreme precision and track the almost literal clockwork motion of the sky. They are engineered carefully, but like any machine they are subject to wear and tear. What’s more, to keep getting the best science, telescopes have to be upgraded from time to time. This changes the telescope’s behavior with time.

The WIYN Telescope ready for a night of collecting pointing data

Because the Earth turns constantly, the sky overhead appears to move at a constant rate. To keep objects in the telescope’s field of view, the earliest telescopes were literally mounted to clocks that moved at the sky’s rate. To make these work, you have to imagine a line in the sky that’s a projection of the Earth’s equator. Then you have to tilt your tracking axis to be at the same angle as that imaginary line in the sky. Another way to think about it is that here at Kitt Peak National Observatory, we’re at 32 degrees north latitude, so you have to tilt your telescope 32 degrees up from the southern horizon to track the sky.

Now, if you look at the photo of the WIYN Telescope above, you’ll notice that it’s mounted flat to the floor and it’s not tipped to match our latitude. That’s because it’s expensive to engineer big heavy telescopes so they can be tipped up at an angle. So, the WIYN telescope actually has to track the sky in two axes: azimuth and elevation, kind of like a radar mount. To track the sky, we have to use computers to adjust the tracking rates constantly. The computers only know how fast to track in each axis if they know where we’re pointing in the sky. If there’s an error in pointing, there’s also an error in tracking.

When I tell people I’m a writer and an astronomer who operates telescopes, it’s often assumed that I have lots of free time on quiet nights at the telescope to write. That doesn’t happen on nights of pointing maps. Instead, it’s a busy night of pointing to a star, noting how far off it was from where we expected it and then moving on again. We do this for anywhere from 75 to 100 stars with a telescope like WIYN and the exercise takes about half the night.

The way pointing and tracking are interconnected also make me think of how I use outlines as a writer. With the telescope, we can imagine that I point to a star and correct the pointing at one spot, then let the telescope track. If the computer thinks the star will be a different point in an hour than it really will be, it will track toward that different point and it won’t follow the star. You need to know where the star really will be in an hour.

For me, an outline is like a little like a pointing map. It tells me where the plot is at point A and it tells me where I want to be once I reach point B. With the telescope, it better be pointed at the star at both points A and B. An outline is more flexible. It’s more like a guideline. I try to listen to my characters when I write my outlines and make sure that points A and B make sense for them. However, sometimes as I write, I find characters do things I didn’t quite imagine the first time. The beauty of an outline is I can change point B. The challenge is that when I do, I realize I may also have to change points C, D, and E as the plot progresses!

I’ve been having a lot of fun rewriting my novel, The Pirates of Sufiro for its 25th anniversary release. I actually wrote some of the original draft when the WIYN telescope was first being built in the 1990s. Rewriting the book is the ultimate case of writing to an outline, especially since I don’t want to change it so much that people can’t pick up older editions of the sequels and follow them. I’m expanding the story and letting my characters breathe more. I’m letting them guide me and asking if what they did entirely made sense for those characters. I’m taking them from point A to point B. Those points can’t really deviate, but I do allow myself to add points A.1, A.2, and A.3 to better explain how they moved from point A to point B.

You can read chapters from the previous edition and see how I’m following my version of a “pointing map” by following me Patreon. My site is at: http://www.patreon.com/davidleesummers

Practice Makes Perfect

I spent last week at Kitt Peak National Observatory assisting with the installation of the Dark Energy Spectrographic Instrument on the Mayall 4-meter Telescope. We spent a couple of months running the refurbished telescope through its paces on the sky with a simple commissioning camera and now it’s time to finish installing the complete instrument. As we get ready to install this complex array of 5000 robot-positioned fibers that feed ten spectrographs, I find myself thinking of the old saw “practice makes perfect.” Well, how exactly do you practice building and installing an instrument no one has built and installed before? As it turns out, there are ways to do this.

One of the major tasks this week has been “dummy” petal installation. The photo above shows a view of the 4-meter telescope from the top. We’re facing the primary mirror (which is covered with white covers that say “Danger: No Step”). In front of that, and right in front of the camera is the prime focus assembly. The 4-meter mirror focuses light into the prime focus assembly. In the old days, a camera sat there. Now there will be 5000-optical fibers aligned with objects on the sky by robot positioners. Those robot positioners are quite delicate and take up a lot of room, so a test petal has been created. The petals fit in the pie-shaped wedges you see in the photo. The dummy petal is the one with Swiss cheese, like holes. It’s carefully guided into position by the red mechanical assembly. Lasers are used to make sure the petal is positioned very carefully and put in at just the right place. Here’s what one of the real petals looks like.

The entire fiber petal sits in the silver box. The black structure on the right is the same size and shape as the Swiss cheese dummy petal. Behind that is a tightly packed array of delicate fibers. The real petal above will have to be placed precisely without breaking anything. So, in this case, we practice by creating a mockup to try out all the procedures and check that we know what we’re doing before we start installing all the really delicate, expensive instrumentation. There will be ten petals like the one in the photo above and light from their fibers will go down to ten spectrographs two floors below the telescope. We currently have six of those spectrographs installed in a clean room.

Currently, three of the spectrographs are in the lower layer of racks. Three are in the upper layer of racks. The spectrographs are where the real science happens. Light that comes down the fibers is spread apart into a literal rainbow and we can see the characteristic fingerprint of the chemical elements of the objects that each fiber in the spectrograph is pointed to.

The spectrographs and the petals remind us that practice makes perfect when you do things repeated times. We’re practicing with the dummy petal, but then we’ll install ten real petals. We’ve installed six spectrographs and we have four more to go. Each time we take another step forward, the easier the process becomes.

Of course, practice made perfect on our way to building these spectrographs in the first place. We built other, smaller fiber spectrographs and learned lessons from their construction. We’ve learned about robotics and we’ve learned lessons from other people who also work in the field by following their work.

Writing is much like this. You practice by doing. You might start with some short stories to get the hang of writing. Then you might try your hand at a novel chapter, then you’ll write another. All the while, you should keep reading to see what others are doing and have done. You’ll learn techniques as you try them out. You will likely encounter difficulties, but as you keep reading, you’ll be sensitive to those difficulties and you’ll see how others have solved them. This is just one of the ways that science has taught me to be a better writer and being a writer has taught me to be better at the science work I do.

You can learn more about my writing at http://www.davidleesummers.com

Seeing Daylight Once Again

As I write this, the DESI Commissioning Instrument run at the Mayall 4-meter telescope at Kitt Peak National Observatory will be nearing completion. The Commissioning Instrument is an array of five digital cameras that view the sky through the telescope’s new optics. Once the Commissioning Instrument comes off, the actual DESI fibers and robot positioners will be assembled at the focal plane. This is a process that’s estimated to take about three months to complete. During that time, I’ll be returning to day shifts at the Mayall telescope, helping with the installation. The DESI fiber “wedges” are starting to arrive and assembly has actually begun on some components down on the telescope’s ground floor.

There is a terrific video describing the DESI project and showing these wedges being populated with the fibers in the lab that you can watch at: https://newscenter.lbl.gov/2018/10/17/dark-energy-project-robots-3d-map-universe/

The DESI fibers are the business end of getting light from distant galaxies where it needs to go to be analyzed. Light traveling for billions of light years will be sent through those fibers to be separated and photographed by spectrographs. Before light gets to the fibers, it has to be collected by the telescope, where it will pass through an optical corrector lens. The corrector makes sure that when the telescope is focused, each fiber will also see an equally focused object. Of course, to do this, the whole instrument has to be aligned well with the primary mirror so we know each target lines up with a fiber.

The goal of the Commissioning Instrument is to give us a simple camera that lets us check that the corrector lens is doing its job. It also allows us to test the alignment and focus mechanism, which we call the hexapod. We want to make sure these critical components work before going to all the work of assembling all those fibers at the top of the telescope. In fact, during the Commissioning Instrument run, we discovered that the corrector was eight millimeters too close to the primary mirror. This was a result of telescope blueprints from 1973 not being updated with as-built specs. Eight millimeters may not sound like much, but it’s enough to keep the fibers from being in focus during the warmest nights of the year! So, the hexapod and corrector assembly were moved, which is much easier to do now than when all the fibers are in place.

I have enjoyed my day shifts at the Mayall this past year. It’s given me a chance to interact with more of the maintenance and engineering crew than I normally do in my nighttime operations. I won’t be working exclusively during the daytime. I will still spend one week a month supporting nighttime observations at the WIYN 3.5-meter telescope. If you would like a behind the scenes look at what it’s like to work at an observatory at night, along with something of a scary story, check out my novel, The Astronomer’s Crypt. You can learn more about the novel at: http://www.davidleesummers.com/Astronomers-Crypt.html